ENSO & IOD
Johnno on Wed 24 Jun 2009 - 17:40
As it looks more and more likely we may be entering into another EL Nino Episode the IOD still remains up in the air some models have changed from a Negative IOD to a weak Positive IOD for the coming months in a space of 4 weeks but going by the ssts the last week things have improved again up there after looking jittery the week before with a cooling period, also the subsurface Eastern Indian ocean is showing the opposite to the Positive IOD thats now predicted anyway here is a sample of what one of the global models think
A few recent dynamic predictions also hint a possibility of a weak positive Indian Ocean Dipole occurring during the same period. However, the subsurface conditions in the tropical Indian Ocean do not attest to this, at least as of now. Further, the historical lead prediction skills for the IOD events are relatively low as compared to those for the El Nino and La Nina events. Nonetheless, given the potential impacts the events may have if they materialize, the evolving conditions in the tropical Pacific and Indian Oceans in the next few months merit careful attention.
http://www2.apcc21.net/climate/climate01_01.php
Still some hope that we may not see a Positive IOD this Winter
Cheers, John.
Outlook released on 24 June, 2009
Welcome New Members! We want to hear from you. Register, stop lurking and start posting!
ENSO & IOD
ENSO & IOD
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Re: ENSO & IOD
Power Storm on Wed 24 Jun 2009 - 18:02
.Yeah John, it's not a given that an El Nino will develop yet, a moderate to high chance maybe, but not a given. It will be wise to pay attention to climatic models and indicaters such as the oceans of the next month or so. Another thing is that I don't find that El Nino's effect Victoria as much as other places, and I stress that it is my opinion that NSW and QLD get affected more, though Victoria does get affected sometimes. And they often bring more thunderstorms too, IMO again! .
Last edited by Power Storm on Fri 26 Jun 2009 - 11:28; edited 1 time in total
Power Storm
Re: ENSO & IOD
droughtbreaker on Thu 25 Jun 2009 - 21:19
.Well, yes they do affect VIC more so than La Nina IMO.
1983 and 1994 were the two big ones which caused extreme drought in those years, but also 1991-1995 event whilst there were some extremely wet spells through that period and overall it was decent rainfall wise for VIC, there were also some very dry spells down here also associated with the El Nino sequence which mainly affected QLD etc. 1993 is a case in point where a potentially dry year was averted by an exceptionally wet spring. 1991 also was exceptionally dry from Feb to May.
A negative IOD saved us apparently and allowed those very wet winter/spring periods to eventuate. If we do not get a negative IOD with this coming El Nino (almost a given to develop) we are in big trouble, and quite frankly it is not looking encouraging at all with that large and intense area of warm anomalies off the horn of Africa (Somalia, Ethiopia etc.) and only weak positive anomalies and much less extensive around the NW coast of AUS.
I am very concerned that as part of the climate change package here in SE Aus is a lack and even absence of -ve phases of the IOD. they just don't happen anymore and if they do it is only very brief, eg. a few months or so..
droughtbreaker
Re: ENSO & IOD
Johnno on Sat 4 Jul 2009 - 12:32
.Well no sign of a +IOD yet after the models decided to swing to a possible +IOD last month for Winter and Spring. Were into the 1st week of July now and the ssts look very good around Indonesia especially off Sumatra and Java & Unlike the past 3 Winters of 06,07,08 we are seeing constant NW cloudbands coming down from there & Northern and Western Vic have already been seeing some results from it the past 6 weeks or so. Got a feeling the models may have this wrong perhaps they have overdone there caculations of a weak +IOD developing in response to the El Nino developing but not always (usually) we get a +IOD with an El Nino and something tells me this year won't be one of those years & have thought this for a while now. The last 3 years by Early July waters were colder than normal off Indonesia but Sub surface under that area also remains warmer than normal so makes me wonder. The Box trees in NW Vic had a profilic & long period of flowering last Spring and Summer which is an indication of rain for the Winter and next Spring and so far NW Vic has done quite well this season.. They didnt flower at all the year before. I'm going to stick with mother nature than the models at the moment .
Johnno
Re: ENSO & IOD
Karl Lijnders on Sat 4 Jul 2009 - 15:22
.Interesting that the models are indicating a large area of precipitation, >250mm, near Sumatra coming into the next week. May spawn a cloudband replacing the one presently over WA.
Might see increased rainfall this month in inland VIC. Potential flood warnings for NE VIC this month if it comes off from next weekend..
Karl Lijnders
Re: ENSO & IOD
Malleefarmer on Sat 4 Jul 2009 - 23:39
.Also some cooling starting to appear off the African coast atm. Not much but a few cool anoms starting to pop up. Looking best in years around Indon so hopefully it can stick around. NWcloudbands are pretty frequent ATM just a pitty we cannot get one to link up and give us a big one to really get flows happening.
Malleefarmer
Re: ENSO & IOD
Malleefarmer on Sun 5 Jul 2009 - 19:47
.Well I know that daily anom charts don't tell the full story but if you look at the lastest one, you would be forgiven to think we are in -IOD territory. Not strong but more warm water on our side..
Malleefarmer
Re: ENSO & IOD
hillybilly on Mon 6 Jul 2009 - 20:46
.The current pattern of SSTs is rather unusual. Really warm across nearly all the tropical oceans. The central/eastern looks almost like a classic El Nino, but the water around Australia looks almost La Nina like - which may well explain recent rain and the abundance of moisture coming in off the Indian OCean.
I'ld expect the eastern Pacific to eventually win out (as this water is warmer, more extensive, and supported by very large anomalies in the sub-surface) and put us into more classical El Nino conditions. Question is does the current abnormal pattern last long enough to set us up for an OK year runoff/crop/bushfire wise. For what they are worth (still experimental) the Bureau's coupled forecasts show wetter than average conditions continuing in the southeast until the start of August then it turning dry for Aug-Sep-Oct (http://poama.bom.gov.au/experimental/po ... p_rain.htm). This would be kinda like 2006, though hopefully not as severe.
I keep expecting a BIG high to develop and stall over eastern Australia marking the start of the El Nino dry, but thankfully that hasn't happened yet..
hillybilly
Re: ENSO & IOD
droughtbreaker on Mon 6 Jul 2009 - 23:18
.Well, it is well known that the 1991-1995 sequence of El Ninos that caused devastating drought in QLD had much less of an impact here. In fact we had some extremely wet periods, second half of 1993 comes to mind as the most spectacular of these. In that period, 1994 had a very strong El nino impact down here and there were brief periods of a few months or so here or there between 1991-1995 that were exceptionally dry also but apart from that we had some really wet periods to balance it out. Apparently this was due to -IOD at times during the El Nino events.
Could this be happening again?.
droughtbreaker
Re: ENSO & IOD
Johnno on Tue 7 Jul 2009 - 12:18
.Perhaps Andrew but not sure. I've also noticed the cooling in the Western and Central Indian Ocean Anthony and as this has happend ssts anomalies in the NE Indian ocean around Indonesia and North of Australia have gotten warmer and expanded so perhaps the models should of stuck to their earlier predictions of a -IOD in March, April & May? Before backflipping in June? Cos from what I am seeing it looks like the earlier predictions may be on track but tim will tell.
Interesting you say DJ that the Eastern and Central Equatioral Pacific is a classic El Nino but other things don't represent it for one the all important SOI both the 30 & 90 day SOI are as Neutral as it can get both near the 0 mark..
Johnno
Re: ENSO & IOD
Johnno on Wed 8 Jul 2009 - 16:05
Taken from the BOM today....
Summary: Strong indicators of El Niño persist
Indicators suggest an El Niño event is developing across the Pacific Basin. Conditions have reached a point that, should they persist at such levels through the remainder of the southern winter and into spring, 2009 will be considered an El Niño year.
Leading climate models indicate that warming of the Pacific will continue for the next few seasons, with very little chance of the current development stalling or reversing.
Continuing El Niño signals include central Pacific Ocean surface temperatures around 1°C above average, and supporting sub-surface temperatures up to 4°C warmer than normal. Trade winds remain weaker than average, and there is an emerging signal of enhanced cloudiness near the date-line
Conversely, the Southern Oscillation Index (SOI) rose over the past week to near zero. However, this would appear to be a response to local weather conditions near Darwin and Tahiti, rather than a long-term climate signal, and hence the SOI is likely to fall again in the weeks ahead.
El Niño events are usually (but not always) associated with below normal rainfall in the second half of the year across large parts of southern and inland eastern Australia.
After many weeks of positive values, the most recent value of the Indian Ocean Dipole (IOD), as measured by the Dipole Mode Index (DMI), was slightly negative. In the past, positive IOD values have been associated with drier conditions through south east Australia in winter and spring.
Johnno
Re: ENSO & IOD
Karl Lijnders on Wed 8 Jul 2009 - 16:40
.Thats a bit more promising!!! Now we need the westerly winds to stand up and start thumping through some frontal boundaries and cold air!!! They can then cut off over VIC!!.
Karl Lijnders
Re: ENSO & IOD
David on Thu 16 Jul 2009 - 11:39
There has been further cooling in the western IOD and a slightly warming in the SE IOD during the past week with the DMI in negative figures. They might start to regret changing there forecast to a +IOD.
http://ioc3.unesco.org/oopc/state_of_the_ocean/all/
http://ioc3.unesco.org/oopc/state_of_th ... nd/dmi.php.
David
Re: ENSO & IOD
Johnno on Fri 17 Jul 2009 - 14:05
Yes David and this backs up whats your saying.. Surpise suprise Dr.Yamagta and his team have made a bit of a turn around back to a possible Negative IOD occuring in its latest (July) model update as of yesterday. El Nino also seems to be all over the place some are saying now this isn't your traditional El Nino and most atmospheric conditions show anything but El Nino across the planet at the moment & wouldn't be suprised if it fizzled out in the next few months anyway here it is.. from Dr. Yamagata and his crew from Sintex...
From Sintex Dr.Yamagata and his crew from the lastest July update...
Toshio Yamagata <yamagata@adm.s.u-tokyo.ac.jp> [2009-07-17 07:33:11 +0900]: > Dear Luo-san:>> This is interesting. The El Nino pattern is very much different from the & gt; conventional one; almost all equatorial region shows positive SST > anomalies with a peak at the central Pacific. It looks like the El Nino > Modoki pattern (as in unusually hot 2004 with so many typoons attacked > Japan) although the central Pacific warming is not sandwiched by cold > anomalies as we showed in Ashok et al. (2007) > [http://www.agu.org/pubs/crossref/2007/2 ... 3798.shtml] and Weng et > al. (2007) > [http://www.springerlink.com/content/a36 ... 08c1b&pi=0]>> If so, we may expect very hot condition in this summer as in 2004. > However, the prediction is just opposite with weaker than normal North > Pacific High. This needs to be watched hereafter.>> Regaring the Indian Ocean, the model predicts basin-wide warming as well > with very slight indication of a <negative > IOD as I expected from my > <empirical> forecast in contrast to the SINTEX-F's prediction (perhaps > biased by too strong Pacific signal) in June
Dear Jing-Jia, Sensei and all, We just had an interesting APEC Climate symposium in Singapore.
One of the things we discussed was the fate of the current El Nino signal. Several folks pointed out that while the oceanic signals were consistent with El Nino (in observations, SST peaks at the eastern Pacific), the atmospheric response is almost non-existent. I myself contributed to the discussionby cautioning that the El Nino like SST anomalies will disappear faster than we expect based on forecasts, becuase the SST anomalies are simply not sustainable under the current atmospheric conditions. It will bevery interesting to see how the El Nino will/will not evolve. My estimate is that the conditions will be back to normal in two months time.
The evolving negative IOD also needs close monitoring. saji
Interesting... We shall see I'm gonna sit on the fence about this one
John..
Johnno
Re: ENSO & IOD
Power Storm on Fri 17 Jul 2009 - 18:52
I still don't think it will happen. I am on natures side at the moment. Besides, its a bit all over the place regarding meteorology terms and El Nino thresholds atm..
_________________
Jake.
The younger generation of weather.
Power Storm on Wed 24 Jun 2009 - 18:02
.Yeah John, it's not a given that an El Nino will develop yet, a moderate to high chance maybe, but not a given. It will be wise to pay attention to climatic models and indicaters such as the oceans of the next month or so. Another thing is that I don't find that El Nino's effect Victoria as much as other places, and I stress that it is my opinion that NSW and QLD get affected more, though Victoria does get affected sometimes. And they often bring more thunderstorms too, IMO again! .
Last edited by Power Storm on Fri 26 Jun 2009 - 11:28; edited 1 time in total
Power Storm
Re: ENSO & IOD
droughtbreaker on Thu 25 Jun 2009 - 21:19
.Well, yes they do affect VIC more so than La Nina IMO.
1983 and 1994 were the two big ones which caused extreme drought in those years, but also 1991-1995 event whilst there were some extremely wet spells through that period and overall it was decent rainfall wise for VIC, there were also some very dry spells down here also associated with the El Nino sequence which mainly affected QLD etc. 1993 is a case in point where a potentially dry year was averted by an exceptionally wet spring. 1991 also was exceptionally dry from Feb to May.
A negative IOD saved us apparently and allowed those very wet winter/spring periods to eventuate. If we do not get a negative IOD with this coming El Nino (almost a given to develop) we are in big trouble, and quite frankly it is not looking encouraging at all with that large and intense area of warm anomalies off the horn of Africa (Somalia, Ethiopia etc.) and only weak positive anomalies and much less extensive around the NW coast of AUS.
I am very concerned that as part of the climate change package here in SE Aus is a lack and even absence of -ve phases of the IOD. they just don't happen anymore and if they do it is only very brief, eg. a few months or so..
droughtbreaker
Re: ENSO & IOD
Johnno on Sat 4 Jul 2009 - 12:32
.Well no sign of a +IOD yet after the models decided to swing to a possible +IOD last month for Winter and Spring. Were into the 1st week of July now and the ssts look very good around Indonesia especially off Sumatra and Java & Unlike the past 3 Winters of 06,07,08 we are seeing constant NW cloudbands coming down from there & Northern and Western Vic have already been seeing some results from it the past 6 weeks or so. Got a feeling the models may have this wrong perhaps they have overdone there caculations of a weak +IOD developing in response to the El Nino developing but not always (usually) we get a +IOD with an El Nino and something tells me this year won't be one of those years & have thought this for a while now. The last 3 years by Early July waters were colder than normal off Indonesia but Sub surface under that area also remains warmer than normal so makes me wonder. The Box trees in NW Vic had a profilic & long period of flowering last Spring and Summer which is an indication of rain for the Winter and next Spring and so far NW Vic has done quite well this season.. They didnt flower at all the year before. I'm going to stick with mother nature than the models at the moment .
Johnno
Re: ENSO & IOD
Karl Lijnders on Sat 4 Jul 2009 - 15:22
.Interesting that the models are indicating a large area of precipitation, >250mm, near Sumatra coming into the next week. May spawn a cloudband replacing the one presently over WA.
Might see increased rainfall this month in inland VIC. Potential flood warnings for NE VIC this month if it comes off from next weekend..
Karl Lijnders
Re: ENSO & IOD
Malleefarmer on Sat 4 Jul 2009 - 23:39
.Also some cooling starting to appear off the African coast atm. Not much but a few cool anoms starting to pop up. Looking best in years around Indon so hopefully it can stick around. NWcloudbands are pretty frequent ATM just a pitty we cannot get one to link up and give us a big one to really get flows happening.
Malleefarmer
Re: ENSO & IOD
Malleefarmer on Sun 5 Jul 2009 - 19:47
.Well I know that daily anom charts don't tell the full story but if you look at the lastest one, you would be forgiven to think we are in -IOD territory. Not strong but more warm water on our side..
Malleefarmer
Re: ENSO & IOD
hillybilly on Mon 6 Jul 2009 - 20:46
.The current pattern of SSTs is rather unusual. Really warm across nearly all the tropical oceans. The central/eastern looks almost like a classic El Nino, but the water around Australia looks almost La Nina like - which may well explain recent rain and the abundance of moisture coming in off the Indian OCean.
I'ld expect the eastern Pacific to eventually win out (as this water is warmer, more extensive, and supported by very large anomalies in the sub-surface) and put us into more classical El Nino conditions. Question is does the current abnormal pattern last long enough to set us up for an OK year runoff/crop/bushfire wise. For what they are worth (still experimental) the Bureau's coupled forecasts show wetter than average conditions continuing in the southeast until the start of August then it turning dry for Aug-Sep-Oct (http://poama.bom.gov.au/experimental/po ... p_rain.htm). This would be kinda like 2006, though hopefully not as severe.
I keep expecting a BIG high to develop and stall over eastern Australia marking the start of the El Nino dry, but thankfully that hasn't happened yet..
hillybilly
Re: ENSO & IOD
droughtbreaker on Mon 6 Jul 2009 - 23:18
.Well, it is well known that the 1991-1995 sequence of El Ninos that caused devastating drought in QLD had much less of an impact here. In fact we had some extremely wet periods, second half of 1993 comes to mind as the most spectacular of these. In that period, 1994 had a very strong El nino impact down here and there were brief periods of a few months or so here or there between 1991-1995 that were exceptionally dry also but apart from that we had some really wet periods to balance it out. Apparently this was due to -IOD at times during the El Nino events.
Could this be happening again?.
droughtbreaker
Re: ENSO & IOD
Johnno on Tue 7 Jul 2009 - 12:18
.Perhaps Andrew but not sure. I've also noticed the cooling in the Western and Central Indian Ocean Anthony and as this has happend ssts anomalies in the NE Indian ocean around Indonesia and North of Australia have gotten warmer and expanded so perhaps the models should of stuck to their earlier predictions of a -IOD in March, April & May? Before backflipping in June? Cos from what I am seeing it looks like the earlier predictions may be on track but tim will tell.
Interesting you say DJ that the Eastern and Central Equatioral Pacific is a classic El Nino but other things don't represent it for one the all important SOI both the 30 & 90 day SOI are as Neutral as it can get both near the 0 mark..
Johnno
Re: ENSO & IOD
Johnno on Wed 8 Jul 2009 - 16:05
Taken from the BOM today....
Summary: Strong indicators of El Niño persist
Indicators suggest an El Niño event is developing across the Pacific Basin. Conditions have reached a point that, should they persist at such levels through the remainder of the southern winter and into spring, 2009 will be considered an El Niño year.
Leading climate models indicate that warming of the Pacific will continue for the next few seasons, with very little chance of the current development stalling or reversing.
Continuing El Niño signals include central Pacific Ocean surface temperatures around 1°C above average, and supporting sub-surface temperatures up to 4°C warmer than normal. Trade winds remain weaker than average, and there is an emerging signal of enhanced cloudiness near the date-line
Conversely, the Southern Oscillation Index (SOI) rose over the past week to near zero. However, this would appear to be a response to local weather conditions near Darwin and Tahiti, rather than a long-term climate signal, and hence the SOI is likely to fall again in the weeks ahead.
El Niño events are usually (but not always) associated with below normal rainfall in the second half of the year across large parts of southern and inland eastern Australia.
After many weeks of positive values, the most recent value of the Indian Ocean Dipole (IOD), as measured by the Dipole Mode Index (DMI), was slightly negative. In the past, positive IOD values have been associated with drier conditions through south east Australia in winter and spring.
Johnno
Re: ENSO & IOD
Karl Lijnders on Wed 8 Jul 2009 - 16:40
.Thats a bit more promising!!! Now we need the westerly winds to stand up and start thumping through some frontal boundaries and cold air!!! They can then cut off over VIC!!.
Karl Lijnders
Re: ENSO & IOD
David on Thu 16 Jul 2009 - 11:39
There has been further cooling in the western IOD and a slightly warming in the SE IOD during the past week with the DMI in negative figures. They might start to regret changing there forecast to a +IOD.
http://ioc3.unesco.org/oopc/state_of_the_ocean/all/
http://ioc3.unesco.org/oopc/state_of_th ... nd/dmi.php.
David
Re: ENSO & IOD
Johnno on Fri 17 Jul 2009 - 14:05
Yes David and this backs up whats your saying.. Surpise suprise Dr.Yamagta and his team have made a bit of a turn around back to a possible Negative IOD occuring in its latest (July) model update as of yesterday. El Nino also seems to be all over the place some are saying now this isn't your traditional El Nino and most atmospheric conditions show anything but El Nino across the planet at the moment & wouldn't be suprised if it fizzled out in the next few months anyway here it is.. from Dr. Yamagata and his crew from Sintex...
From Sintex Dr.Yamagata and his crew from the lastest July update...
Toshio Yamagata <yamagata@adm.s.u-tokyo.ac.jp> [2009-07-17 07:33:11 +0900]: > Dear Luo-san:>> This is interesting. The El Nino pattern is very much different from the & gt; conventional one; almost all equatorial region shows positive SST > anomalies with a peak at the central Pacific. It looks like the El Nino > Modoki pattern (as in unusually hot 2004 with so many typoons attacked > Japan) although the central Pacific warming is not sandwiched by cold > anomalies as we showed in Ashok et al. (2007) > [http://www.agu.org/pubs/crossref/2007/2 ... 3798.shtml] and Weng et > al. (2007) > [http://www.springerlink.com/content/a36 ... 08c1b&pi=0]>> If so, we may expect very hot condition in this summer as in 2004. > However, the prediction is just opposite with weaker than normal North > Pacific High. This needs to be watched hereafter.>> Regaring the Indian Ocean, the model predicts basin-wide warming as well > with very slight indication of a <negative > IOD as I expected from my > <empirical> forecast in contrast to the SINTEX-F's prediction (perhaps > biased by too strong Pacific signal) in June
Dear Jing-Jia, Sensei and all, We just had an interesting APEC Climate symposium in Singapore.
One of the things we discussed was the fate of the current El Nino signal. Several folks pointed out that while the oceanic signals were consistent with El Nino (in observations, SST peaks at the eastern Pacific), the atmospheric response is almost non-existent. I myself contributed to the discussionby cautioning that the El Nino like SST anomalies will disappear faster than we expect based on forecasts, becuase the SST anomalies are simply not sustainable under the current atmospheric conditions. It will bevery interesting to see how the El Nino will/will not evolve. My estimate is that the conditions will be back to normal in two months time.
The evolving negative IOD also needs close monitoring. saji
Interesting... We shall see I'm gonna sit on the fence about this one
John..
Johnno
Re: ENSO & IOD
Power Storm on Fri 17 Jul 2009 - 18:52
I still don't think it will happen. I am on natures side at the moment. Besides, its a bit all over the place regarding meteorology terms and El Nino thresholds atm..
_________________
Jake.
The younger generation of weather.
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Re: ENSO & IOD
droughtbreaker on Sun 19 Jul 2009 - 23:56
.Current indications are not pointing towards a full blown El Nino. There are warm anomalies in the Coral sea atm and also off the NW of Aus. Very interesting to here we may be heading into a -ve IOD, could almost be another 1991-1993 scenario up ahead and also 1995. With the PDO phase in our favour there is a good chance the El Nino signature may peter out as John mentioned and in that case we could have some very wet years ahead. Can only hope atm but it would be great to see..
droughtbreaker
Re: ENSO & IOD
Anthony Violi on Wed 22 Jul 2009 - 19:26
Andrew, i guess the best way to tell is to look at historical records as to the relationship between the two. Maybe someone who has more time than me can look into this. Recently we have +IOD and La Nina simultaneously. And furthermore, a weak El Nino and weak - IOD would indicate some correlation in the coming months. And another thing, how long has there been records for IOD?.
Anthony Violi
Re: ENSO & IOD
Johnno on Fri 24 Jul 2009 - 12:21
Don't know about you guys and it might just be early days but looking at the pattern and the general feel over the coming weeks its starting to look El Ninoish to me with no moisture at all over the inland Australia or Eastern Australia by Late July/August you tend to know what is really going on in years like this. The Setup over the coming weeks is starting to look like a combination of the 1994 and 2002 El Ninos both these Winter and Springs highs tended to dominate the inland with the Westerly belt bringing some relief to far Southern coasts of Australia (more exposed than anything else and Western Tassie).
The 2006 effects of El Nino was different.. Instead of having a dominant Westerly flow around tassie most of that season we got alot of strong highs developing well south of the Bight moving NE into the Tasman sea so all in all even the westerly belt was preety much non existant so Exposed coastal areas and Western tassie also remained quite dry as well as coastal NSW as the Highs moved NE right over that area so all in all the Westerlies were cut off as were the Easterlies for the NSW coast.. Be interesting to compare in coming weeks and months but it does look to me to have a feel of the 1994 and 2002 El Ninos, at least this way Far Coastal areas may get some relief over the coming weeks and months if this pattern were to remain unlike 2006 but could remain mostly dry inland for the rest of the year.
It wouldn't suprise me if parts of NSW and Southern/SE Qld end up with a record dry in some areas for the last 6 months of the year there (July-December) mother nature works in funny ways and after the incredible wet up there the 1st 6 months this year and the past 2 years in general I kind of expect this to happen now if July is anything to go by after being so dry up there this month(rainless in some areas even for July standards thats very poor considering Brisbanes & other places up there averages are actually bit wetter than Melbourne for July) I expect this pattern to continue the coming months up there with the dry extending right into Victoria with the odd brief interuption of wet spells for Coastal areas of Victoria. Anyway thats my 2c worth and how I see things for the coming months feel free to shoot me down in flames .
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 24 Jul 2009 - 12:57
Could not agree with you more. EC screamed El Nino this morning in it's run to me..
Karl Lijnders
Re: ENSO & IOD
hillybilly on Sat 25 Jul 2009 - 8:51
Agree totally Karl. The next week or two doesn't look good. Hopefully the far south will scrape some rain, but further north it is looking rainless (after a tiny bit of patchy rain on Sunday). Also have noticed that the models are shifting back to the "down grade everything" mode.
Worth keeping an eye on the two week and monthly rainfall forecasts at http://poama.bom.gov.au/experimental/po ... p_rain.htm (this model includes an ocean and so tracks the evolution of El Nino/IOD etc). POAMA predicted a "wet" July but conditions turning drier from August onwards (initially in NSW and spreading south). This suggest August is likely to be dry in the southeast .
hillybilly
Re: ENSO & IOD
droughtbreaker on Sat 25 Jul 2009 - 11:23
.We have patterns like this all the time these days, whether it is El Nino, La Nina or whatever it is, it is our new climate and I have been waiting for the next period of high domination for most of this month because we rarely go more than a month or two without one. July is still shaping up as below average for here and probably most places despite heaps of strong cold fronts and lows. .
droughtbreaker
Re: ENSO & IOD
hillybilly on Thu 30 Jul 2009 - 9:53
Usually (not always 1983 is an example) The Summers of an El Nino (weakening) get moister and more humid Andrew.. Summer of 97/98 was that way with regular rainfall in Jan and Feb after December being so dry, Summer of 94/95 was that way too exactly like 97/98 with Dec being dry and hot, Summer of 2002/2003 was that way but Mainly Feb that year was moister & Summer of 06/07 we saw lack of Northerlies and humid ENE winds instead through Jan and Feb so perhaps not all doom and gloom but the next 5 months do worry me.
Johnno, just a few rambling observations. One characteristics of El Ninos is enhanced westerlies over the oceans south of Australia which in some years can actually sneak far enough north to deliver rain in coastal areas. This looks to be happening ATM, and was certainly a feature of 1994 (when we had lots of westerly gales and a few solid showery fronts). If this pattern continues we may take the edge off the likely "El Nino" - fingers crossed. However, this pattern usually weakens by Nov/Dec when one almost always seems to shift to a pattern of high temperatures and dry conditions - this was certainly the case in 1994, 1997, 2002 and 2006.
As for the break down, the key is timing. Summer is usually the transition season for the breakdown of El Nino. If the breakdown happens early (such as 1995, 2007) we escape some of the worst effects. If it happens late - 1982, 2002 then summers can be downright horrible for the southeast with fire seasons which drag right through into autumn the following year. I doubt we can predict the exact timing of the break down of the El Nino influence, but my dumb observation is about half of the El Ninos seem to loose their grips in the first half of summer and the rest somewhat later.
PS notice the SOI is diving south http://www.longpaddock.qld.gov.au/Seaso ... SOIValues/ and the cloud bands out of the Indian Ocean have gone (with the IOD moving into positive territory). It looks to me like the El Nino is now gaining influence over Australia..
hillybilly
Re: ENSO & IOD
Johnno on Thu 30 Jul 2009 - 14:00
Thanks for that David. I do remember 1994 and was quite showery right through August to October with some good cold outbreaks right through that period but yes most of the time by November El Nino has taken a grip on most of the nation and can last into the Summer but as you say some Summers it may lose its grip earlier other Summers well into the Summer.
Theres hasn't been any cloud or moisture from the Indian Ocean for a fornight now Ssts anomalies are also becoming more negative up there. Not looking good..
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 31 Jul 2009 - 21:15
Thankfully the el niño trend is developing at the time when the westerly belt is most active. This is keeping the south nice and wet at the moment. Looks like frontal weather to continue for the future outlook. Looks as if the PW within the westerly belt is enough to support reasonable rainfall.
Need this to continue to years end!!!!.
Karl Lijnders
Re: ENSO & IOD
droughtbreaker on Sat 1 Aug 2009 - 0:34
Probably clutching at straws here but it is worth noting that in January 1983 at the height of that horrific El Nino there were only 3 days above 30C in Melbourne (all above 35C) and 12 days below 20C. The average max temp ended up 1.6C below the long term average. In December 1982 the average max temperature was 0.4C below the long term mean and 47.4mm of rain in the city, (we had 75.1mm here), all be it almost entirely out of a major rain event or storm outbreak? around the 8th to the 10th. A similar pattern of long runs of cool days broken by a very hot day or two prevailed.
Feb 1983 was a real 'up and down' affair with exceptionally intense heatwaves breaking up mild periods of weather at regular intervals. Unfortunately those intense heatwaves were accompanied by nasty gales ahead of approaching cold fronts which, along with the extreme dry over most of the previous year, fueled the Ash Wednesday fires.
Compare this to January and February this year when we actually had a bit of a La Nina going, the heat was incessant and record breaking with very few even remotely cool days in amongst it save for the odd day about the coast and bays when seabreezes were in effect. Rainfall was almost non existent through most of the state in Jan and Feb (even in 1983 at least we got something worthwhile i.e. 21.1mm here in Jan), we had quite a few days with gale force wind, basically it ended up many times worse than the 1983 El Nino summer.
Again, probably clutching at straws, but in no way does El Nino have to automatically mean things are going to be worse than ever this summer. I don't see how anything could be worse than last summer. Given we are probably unlikely to have an El Nino anywhere near the magnitude of 1982/1983 which was massive, there is still a bit of 'hope' there.
Basically IMO, El Nino, La Nina or neutral it doesn't matter anymore, the main issue is climate change in general and the fact that any year can bring with it horrific weather in summer here in the SE..
droughtbreaker
Re: ENSO & IOD
Anthony Violi on Sat 1 Aug 2009 - 8:16
Your right Andrew, El Nino means nothing in regards to this. What is important is the amount of rainfall we have had. Last 13 years been very dry so that in itself means the fire risk is much higher. For us to have a worse fire year than last summer, we would need to be very very unlucky.
First off, it rained a fair bit in Nov/Dec 08, first time grass was green at Xmas time in many years. This provided so much fuel when the heatwave came that it was an unstoppable force. This year been very dry also so the amount of fuel in theory should be less. So unless we get good rains again early on in the summer, i would think it wont reach the biblical proportions we saw 6 months ago.
And we wont see 47 again with those gales, virtually all the planets aligned that day for a once in many years event..
Anthony Violi
Re: ENSO & IOD
hillybilly on Sat 1 Aug 2009 - 16:16
First thing to remember is that global warming is changing everything - the source region for our heatwave (about 20S) is warming up rather quickly (http://www.bom.gov.au/cgi-bin/climate/c ... eriod=1970). It's a noise trend, but essentially now we have air that is frequently extremely hot ready to dive south.
You actually find that El Nino summers are usually "cooler than average" but have a small number of very dry very hot windy days. In contrast, La Nina summers are usually "warmer than average" but most usually lack very dry hot windy days. La Nina summers tend to have a lot of northeasterlies and El Nina summers tend to have a lot of southwesterlies. This is in the average - however - as I'll explain below...
As it turns out the two hottest spells in Victoria's history - 1939 and 2009 were both La Nina summers. These were both characterised by a extended block with little change in air mass. I suspect there is a bit of sting in the tail of the northeasterly pattern common in La Nina. The La Nina pattern means the summers are often very blocked and occasionally these blocks lead to the build up of extreme heat..
hillybilly
Re: ENSO & IOD
Johnno on Fri 14 Aug 2009 - 0:44
Interesting about how El Nino Summers and Nina summers usually work there DJ thanks for that.
Speaking of.. Whats your and others thoughts on this? Latest Equatiorial sub-surface...
http://www.bom.gov.au/bmrc/ocean/result ... r/2009/Aug
Well to me looks like the warm sub-surface has weakened quite alot of late with a Cool patch now showing up in the Eastern sub-surface equatioral. interesting now how the NASA Model now peaks this NINO in the coming weeks (September early October) rather than November, December as it was orginally... Looks like in general this El Nino may be running out of puff already very unusual to have the Equatioral sub-surface weakening this much in August isn't it? It didn't happen in 1997, 2002 and 2006 unless theres another explaination for this?.
John
Re: ENSO & IOD
Karl Lijnders on Sat 15 Aug 2009 - 20:35
Very interesting developments there John. Do we take it seriously considering that August is not usually the time for El Ninos to break down?.
Karl Lijnders
Re: ENSO & IOD
windyrob on Sun 16 Aug 2009 - 11:46
Apparently this is the first el nino to come off the back of la nina in over 30 years (ie since the PDO was last negative)
Under this scenario they tend to be small and short lived. I suspect that a lot of the energy may be used up neutralising the negative anomalies of the la nina which reduces the power of the el nino to force the rest of the system.
I also suspect that part of the initial heating mechanism of el nino is disruption of convection over the western warm pool. this leads to energetic imbalance that allows the ocean to warm since cooling is reduced. After a period of time the convection becomes re-established (potentially in another area) and the oceans start transferring energy to the atmosphere again.
This would explain the lag between ocean temp and satellite temps. It would also mean that the amount of lag is proportional to the amount of ocean heating and size of el nino.
In the 97/8 el nino there was a long lag and a large el nino. The current warming period had a very short lag, very little negative OLR anomolies, and may not even reach official el nino status, unless we get a second round of warming.
Cheers.
windyrob
droughtbreaker on Sun 19 Jul 2009 - 23:56
.Current indications are not pointing towards a full blown El Nino. There are warm anomalies in the Coral sea atm and also off the NW of Aus. Very interesting to here we may be heading into a -ve IOD, could almost be another 1991-1993 scenario up ahead and also 1995. With the PDO phase in our favour there is a good chance the El Nino signature may peter out as John mentioned and in that case we could have some very wet years ahead. Can only hope atm but it would be great to see..
droughtbreaker
Re: ENSO & IOD
Anthony Violi on Wed 22 Jul 2009 - 19:26
droughtbreaker wrote:
Well, it is well known that the 1991-1995 sequence of El Ninos that caused devastating drought in QLD had much less of an impact here. In fact we had some extremely wet periods, second half of 1993 comes to mind as the most spectacular of these. In that period, 1994 had a very strong El nino impact down here and there were brief periods of a few months or so here or there between 1991-1995 that were exceptionally dry also but apart from that we had some really wet periods to balance it out. Apparently this was due to -IOD at times during the El Nino events.
Could this be happening again?
Andrew, i guess the best way to tell is to look at historical records as to the relationship between the two. Maybe someone who has more time than me can look into this. Recently we have +IOD and La Nina simultaneously. And furthermore, a weak El Nino and weak - IOD would indicate some correlation in the coming months. And another thing, how long has there been records for IOD?.
Anthony Violi
Re: ENSO & IOD
Johnno on Fri 24 Jul 2009 - 12:21
Don't know about you guys and it might just be early days but looking at the pattern and the general feel over the coming weeks its starting to look El Ninoish to me with no moisture at all over the inland Australia or Eastern Australia by Late July/August you tend to know what is really going on in years like this. The Setup over the coming weeks is starting to look like a combination of the 1994 and 2002 El Ninos both these Winter and Springs highs tended to dominate the inland with the Westerly belt bringing some relief to far Southern coasts of Australia (more exposed than anything else and Western Tassie).
The 2006 effects of El Nino was different.. Instead of having a dominant Westerly flow around tassie most of that season we got alot of strong highs developing well south of the Bight moving NE into the Tasman sea so all in all even the westerly belt was preety much non existant so Exposed coastal areas and Western tassie also remained quite dry as well as coastal NSW as the Highs moved NE right over that area so all in all the Westerlies were cut off as were the Easterlies for the NSW coast.. Be interesting to compare in coming weeks and months but it does look to me to have a feel of the 1994 and 2002 El Ninos, at least this way Far Coastal areas may get some relief over the coming weeks and months if this pattern were to remain unlike 2006 but could remain mostly dry inland for the rest of the year.
It wouldn't suprise me if parts of NSW and Southern/SE Qld end up with a record dry in some areas for the last 6 months of the year there (July-December) mother nature works in funny ways and after the incredible wet up there the 1st 6 months this year and the past 2 years in general I kind of expect this to happen now if July is anything to go by after being so dry up there this month(rainless in some areas even for July standards thats very poor considering Brisbanes & other places up there averages are actually bit wetter than Melbourne for July) I expect this pattern to continue the coming months up there with the dry extending right into Victoria with the odd brief interuption of wet spells for Coastal areas of Victoria. Anyway thats my 2c worth and how I see things for the coming months feel free to shoot me down in flames .
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 24 Jul 2009 - 12:57
Could not agree with you more. EC screamed El Nino this morning in it's run to me..
Karl Lijnders
Re: ENSO & IOD
hillybilly on Sat 25 Jul 2009 - 8:51
Agree totally Karl. The next week or two doesn't look good. Hopefully the far south will scrape some rain, but further north it is looking rainless (after a tiny bit of patchy rain on Sunday). Also have noticed that the models are shifting back to the "down grade everything" mode.
Worth keeping an eye on the two week and monthly rainfall forecasts at http://poama.bom.gov.au/experimental/po ... p_rain.htm (this model includes an ocean and so tracks the evolution of El Nino/IOD etc). POAMA predicted a "wet" July but conditions turning drier from August onwards (initially in NSW and spreading south). This suggest August is likely to be dry in the southeast .
hillybilly
Re: ENSO & IOD
droughtbreaker on Sat 25 Jul 2009 - 11:23
.We have patterns like this all the time these days, whether it is El Nino, La Nina or whatever it is, it is our new climate and I have been waiting for the next period of high domination for most of this month because we rarely go more than a month or two without one. July is still shaping up as below average for here and probably most places despite heaps of strong cold fronts and lows. .
droughtbreaker
Re: ENSO & IOD
hillybilly on Thu 30 Jul 2009 - 9:53
Usually (not always 1983 is an example) The Summers of an El Nino (weakening) get moister and more humid Andrew.. Summer of 97/98 was that way with regular rainfall in Jan and Feb after December being so dry, Summer of 94/95 was that way too exactly like 97/98 with Dec being dry and hot, Summer of 2002/2003 was that way but Mainly Feb that year was moister & Summer of 06/07 we saw lack of Northerlies and humid ENE winds instead through Jan and Feb so perhaps not all doom and gloom but the next 5 months do worry me.
Johnno, just a few rambling observations. One characteristics of El Ninos is enhanced westerlies over the oceans south of Australia which in some years can actually sneak far enough north to deliver rain in coastal areas. This looks to be happening ATM, and was certainly a feature of 1994 (when we had lots of westerly gales and a few solid showery fronts). If this pattern continues we may take the edge off the likely "El Nino" - fingers crossed. However, this pattern usually weakens by Nov/Dec when one almost always seems to shift to a pattern of high temperatures and dry conditions - this was certainly the case in 1994, 1997, 2002 and 2006.
As for the break down, the key is timing. Summer is usually the transition season for the breakdown of El Nino. If the breakdown happens early (such as 1995, 2007) we escape some of the worst effects. If it happens late - 1982, 2002 then summers can be downright horrible for the southeast with fire seasons which drag right through into autumn the following year. I doubt we can predict the exact timing of the break down of the El Nino influence, but my dumb observation is about half of the El Ninos seem to loose their grips in the first half of summer and the rest somewhat later.
PS notice the SOI is diving south http://www.longpaddock.qld.gov.au/Seaso ... SOIValues/ and the cloud bands out of the Indian Ocean have gone (with the IOD moving into positive territory). It looks to me like the El Nino is now gaining influence over Australia..
hillybilly
Re: ENSO & IOD
Johnno on Thu 30 Jul 2009 - 14:00
Thanks for that David. I do remember 1994 and was quite showery right through August to October with some good cold outbreaks right through that period but yes most of the time by November El Nino has taken a grip on most of the nation and can last into the Summer but as you say some Summers it may lose its grip earlier other Summers well into the Summer.
Theres hasn't been any cloud or moisture from the Indian Ocean for a fornight now Ssts anomalies are also becoming more negative up there. Not looking good..
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 31 Jul 2009 - 21:15
Thankfully the el niño trend is developing at the time when the westerly belt is most active. This is keeping the south nice and wet at the moment. Looks like frontal weather to continue for the future outlook. Looks as if the PW within the westerly belt is enough to support reasonable rainfall.
Need this to continue to years end!!!!.
Karl Lijnders
Re: ENSO & IOD
droughtbreaker on Sat 1 Aug 2009 - 0:34
Probably clutching at straws here but it is worth noting that in January 1983 at the height of that horrific El Nino there were only 3 days above 30C in Melbourne (all above 35C) and 12 days below 20C. The average max temp ended up 1.6C below the long term average. In December 1982 the average max temperature was 0.4C below the long term mean and 47.4mm of rain in the city, (we had 75.1mm here), all be it almost entirely out of a major rain event or storm outbreak? around the 8th to the 10th. A similar pattern of long runs of cool days broken by a very hot day or two prevailed.
Feb 1983 was a real 'up and down' affair with exceptionally intense heatwaves breaking up mild periods of weather at regular intervals. Unfortunately those intense heatwaves were accompanied by nasty gales ahead of approaching cold fronts which, along with the extreme dry over most of the previous year, fueled the Ash Wednesday fires.
Compare this to January and February this year when we actually had a bit of a La Nina going, the heat was incessant and record breaking with very few even remotely cool days in amongst it save for the odd day about the coast and bays when seabreezes were in effect. Rainfall was almost non existent through most of the state in Jan and Feb (even in 1983 at least we got something worthwhile i.e. 21.1mm here in Jan), we had quite a few days with gale force wind, basically it ended up many times worse than the 1983 El Nino summer.
Again, probably clutching at straws, but in no way does El Nino have to automatically mean things are going to be worse than ever this summer. I don't see how anything could be worse than last summer. Given we are probably unlikely to have an El Nino anywhere near the magnitude of 1982/1983 which was massive, there is still a bit of 'hope' there.
Basically IMO, El Nino, La Nina or neutral it doesn't matter anymore, the main issue is climate change in general and the fact that any year can bring with it horrific weather in summer here in the SE..
droughtbreaker
Re: ENSO & IOD
Anthony Violi on Sat 1 Aug 2009 - 8:16
Your right Andrew, El Nino means nothing in regards to this. What is important is the amount of rainfall we have had. Last 13 years been very dry so that in itself means the fire risk is much higher. For us to have a worse fire year than last summer, we would need to be very very unlucky.
First off, it rained a fair bit in Nov/Dec 08, first time grass was green at Xmas time in many years. This provided so much fuel when the heatwave came that it was an unstoppable force. This year been very dry also so the amount of fuel in theory should be less. So unless we get good rains again early on in the summer, i would think it wont reach the biblical proportions we saw 6 months ago.
And we wont see 47 again with those gales, virtually all the planets aligned that day for a once in many years event..
Anthony Violi
Re: ENSO & IOD
hillybilly on Sat 1 Aug 2009 - 16:16
First thing to remember is that global warming is changing everything - the source region for our heatwave (about 20S) is warming up rather quickly (http://www.bom.gov.au/cgi-bin/climate/c ... eriod=1970). It's a noise trend, but essentially now we have air that is frequently extremely hot ready to dive south.
You actually find that El Nino summers are usually "cooler than average" but have a small number of very dry very hot windy days. In contrast, La Nina summers are usually "warmer than average" but most usually lack very dry hot windy days. La Nina summers tend to have a lot of northeasterlies and El Nina summers tend to have a lot of southwesterlies. This is in the average - however - as I'll explain below...
As it turns out the two hottest spells in Victoria's history - 1939 and 2009 were both La Nina summers. These were both characterised by a extended block with little change in air mass. I suspect there is a bit of sting in the tail of the northeasterly pattern common in La Nina. The La Nina pattern means the summers are often very blocked and occasionally these blocks lead to the build up of extreme heat..
hillybilly
Re: ENSO & IOD
Johnno on Fri 14 Aug 2009 - 0:44
Interesting about how El Nino Summers and Nina summers usually work there DJ thanks for that.
Speaking of.. Whats your and others thoughts on this? Latest Equatiorial sub-surface...
http://www.bom.gov.au/bmrc/ocean/result ... r/2009/Aug
Well to me looks like the warm sub-surface has weakened quite alot of late with a Cool patch now showing up in the Eastern sub-surface equatioral. interesting now how the NASA Model now peaks this NINO in the coming weeks (September early October) rather than November, December as it was orginally... Looks like in general this El Nino may be running out of puff already very unusual to have the Equatioral sub-surface weakening this much in August isn't it? It didn't happen in 1997, 2002 and 2006 unless theres another explaination for this?.
John
Re: ENSO & IOD
Karl Lijnders on Sat 15 Aug 2009 - 20:35
Very interesting developments there John. Do we take it seriously considering that August is not usually the time for El Ninos to break down?.
Karl Lijnders
Re: ENSO & IOD
windyrob on Sun 16 Aug 2009 - 11:46
Apparently this is the first el nino to come off the back of la nina in over 30 years (ie since the PDO was last negative)
Under this scenario they tend to be small and short lived. I suspect that a lot of the energy may be used up neutralising the negative anomalies of the la nina which reduces the power of the el nino to force the rest of the system.
I also suspect that part of the initial heating mechanism of el nino is disruption of convection over the western warm pool. this leads to energetic imbalance that allows the ocean to warm since cooling is reduced. After a period of time the convection becomes re-established (potentially in another area) and the oceans start transferring energy to the atmosphere again.
This would explain the lag between ocean temp and satellite temps. It would also mean that the amount of lag is proportional to the amount of ocean heating and size of el nino.
In the 97/8 el nino there was a long lag and a large el nino. The current warming period had a very short lag, very little negative OLR anomolies, and may not even reach official el nino status, unless we get a second round of warming.
Cheers.
windyrob
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Re: ENSO & IOD
Johnno on Mon 17 Aug 2009 - 18:59
Great to see you Rob thanks for your input.
Yeah Karl heres the latest BOM site updated today 17th August and we can see how much the positive sub-surface anomalies have weakened the past few weeks since July wouldn't suprise me to see this El Nino finished before even the end of year this isn't how things normally pan out in a traditional El Nino August. Love to hear your thoughts DJ?
http://www.bom.gov.au/bmrc/ocean/result ... 09/Aug.gif
And here it is looking it from another angle at 150 metres sub-surface level and as you can see ssts are almost back to Neutral East of about 160W along the Equator back to South America with the warmest Ssts now laying West & North of there
http://www.bom.gov.au/bmrc/ocean/result ... 09/Aug.gif
Starting to look messy and very disorgainsed to me.
Johnno
Re: ENSO & IOD
hillybilly on Wed 19 Aug 2009 - 20:43
Latest BoM outlook was updated today http://www.bom.gov.au/climate/enso/ . The current event is shaping up as very messy - the waters around northern Australia are staying very warm (when they should be cooling) and the Indian Ocean dipole is refusing to go positive. This would suggests that the rainfall response for OZ will be tempered somewhat by local moisture sources.
It's possible the odd behaviour of the SOI reflects the record heatwave which has lead to lower pressures in the north as the spring heat lows comes a month early..
hillybilly
Re: ENSO & IOD
Johnno on Tue 25 Aug 2009 - 13:45
Johnno wrote:
It wouldn't suprise me if parts of NSW and Southern/SE Qld end up with a record dry in some areas for the last 6 months of the year there (July-December) mother nature works in funny ways and after the incredible wet up there the 1st 6 months this year and the past 2 years in general I kind of expect this to happen now if July is anything to go by after being so dry up there this month(rainless in some areas even for July standards thats very poor considering Brisbanes & other places up there averages are actually bit wetter than Melbourne for July) I expect this pattern to continue the coming months up there with the dry extending right into Victoria with the odd brief interuption of wet spells for Coastal areas of Victoria. Anyway thats my 2c worth and how I see things for the coming months feel free to shoot me down in flames
Well still 4 months to go til the end of the year but I made that comment over a month ago and since then thats exactly how its been happening we have had some OK or SPORATIC rain down here in Victoria as a whole since that comment so far but record HEAT & with it record DRY has started in Northern NSW and Qld as I predicted back in July and I expect this to continue well into Spring up there and see records broken in both the Dry side and temp side of things in the coming months (Its already been happening).
Johnno
Re: ENSO & IOD
hillybilly on Wed 26 Aug 2009 - 20:56
BTW looks like the stop-start El Nino is now back on. There has been a very strong westerly wind burst move across the Pacific with a rapid warming of surface and subsurface waters. This will probably be the last kick the system needs to flip into a full blown El Nino (as has been predicted by the models all year).
The weather over OZ is actually pretty El Nino like - though perhaps the westerlies are a little further north than usual (which is why Tas/Vic/southern SA are doing OK). Hopefully the westerlies continue....
hillybilly
Re: ENSO & IOD
Johnno on Mon 31 Aug 2009 - 18:23
Winter 2009 Deciles
http://www.bom.gov.au/cgi-bin/silo/rain ... ime=latest
August 2009 Deciles
http://www.bom.gov.au/cgi-bin/silo/rain ... ime=latest
Lucky Tassie!!! And El Nino starting to take hold in the Eastern states mainly NSW and Qld.
Johnno
Re: ENSO & IOD
Karl Lijnders on Mon 31 Aug 2009 - 19:45
http://www.bom.gov.au/cgi-bin/silo/rain ... ime=latest
Guess that puts it into perspective!!!.
Karl Lijnders
Re: ENSO & IOD
droughtbreaker on Tue 1 Sep 2009 - 0:30
The decile maps for winter and August are a good graphical description of just how dominant NW to W winds have been over the past 3 months with areas in lee of the ranges in VIC below average yet again thanks to the west central rain shadow and almost all of Tas above or well above average, basically the more vigorous the westerlies the higher the rainfall for Tas, particularly the western half of that state.
El Nino getting organised now and ready to unleash on us later into Spring. The good August rains (and likely to continue through the first half of September) are a godsend given the outlook for the second half of spring would be a bit grim at this stage. Hopefully it can be a weak and short lived El Nino this time. Good to see the atmosphere hasn't really responded that much yet with SOI figures remaining neutral..
droughtbreaker
Re: ENSO & IOD
hillybilly on Fri 9 Oct 2009 - 21:00
Reflecting the El Nino September 2009 has come out as the hottest September on record on the earth's surface according to NASA GIS.
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
2009 is now likely to be the second warmest (if not warmest) on record. With an El Nino 2010 is likely to be even hotter..
hillybilly
Re: ENSO & IOD
droughtbreaker on Fri 9 Oct 2009 - 21:24
Makes us all the more fortunate to have had such cool and wet weather for a prolonged period in the middle of one of the warmest periods for the globe..
droughtbreaker
Re: ENSO & IOD
Karl Lijnders on Fri 9 Oct 2009 - 22:21
.Well we certainly helped at the start of the year, now the rest of the planet can have a turn... .
Karl Lijnders
Re: ENSO & IOD
David on Sat 10 Oct 2009 - 11:10
Recent rainfall across southeastern Australia gives further proof that ENSO itself has little effect on us.
SST are warming up again across northern Australia after a brief cool down although we are moving into the time of the year where the northern SST effect is reduced..
David
Re: ENSO & IOD
hillybilly on Sun 11 Oct 2009 - 8:43
David ENSO has a decent impact on us - but it tends to operate through the Indian Ocean which usually, but not always, follows the lead of ENSO. The last two spring we had a +ve Indian Ocean dipole (despite a weak La Nina) which is at least a partial explanation for the dismal rainfall despite La Nina. In contrast this year we have had a near zero Indian Ocean Dipole and rainfall has been pretty close to average.
If you look back through the history about every second El Nino has given "drought" to southeast Australia, so about every second one didn't. However, it has been a bit worse than that in recent years.....
1994 was a drought, 1997 was a drought in parts, 2002 was a terrible drought, 2006 was a terrible drought, 2009 has been OK in many areas..
hillybilly
Re: ENSO & IOD
droughtbreaker on Sun 11 Oct 2009 - 11:10
What we are seeing now is not a 'proper' El Nino. I don't think it has actually been declared as one yet, it hasn't met the criteria. Similar to the last La Nina which only very briefly met the criteria but even so I never remember it actually being formally declared although pretty sure it was a genuine La Nina.
A full blown El Nino, the concept that I have of it anyway, develops earlier in the year, around mid Autumn to Winter and lasts for a whole year or relatively close to that on average. The SOI clearly mirrors what is happening with the oceans and vice versa and there is reinforcing feedback between those two variables that keep the event developing and persisting. Eventually the IOD generally goes positive as anomalously cool water flows across Northern Aus from the western Pacific and into the eastern Indian Ocean. I think the mechanism that causes this is called the 'Indonesian throughflow'.
This just hasn't happened this year and I put it down to a weak and disorganised warm neutral SST pattern in the Pacific that just hasn't been able to evolve into an organised El Nino event. Of course we could still get one developing next year but with the cool phase PDO in place this should be less likely than at other times in the past decade or two.
Still this is just my amateur knowledge, I don't profess to know all that much about this but that's the way i interpret the situation atm..
droughtbreaker
Re: ENSO & IOD
droughtbreaker on Sun 11 Oct 2009 - 11:19
Looking at the latest SST anomalies I can see another solid influx of warmer water heading east-west across northern AUS towards the eastern Indian Ocean whilst, at the other end, there is a rather intense cold patch off the equatorial South American coast. Without wanting to be premature about things it looks like this warm neutral pattern is definitely on the way out just going from current indications.
No signs whatsoever that the 'tap will be turned off' over the next month or so at least. If anything we should continue to see good rainfall..
droughtbreaker
Re: ENSO & IOD
hillybilly on Mon 12 Oct 2009 - 21:04
What we are seeing now is not a 'proper' El Nino.
Unless things develop quickly, I suspect this event will be a non-event. It reminds me of the protracted warm Pacific Conditions which pretty much dominated from about 2001 to 2006 and is more global warming than "El Nino". The temperatures which have been seen in the central/eastern Pacific are certainly warm enough to be labeled "El Nino" but at the same time waters northern Australia has been very warm (also).
The big worry then is that if this build up of heat is not El Nino - then what happens when we actually get a full blown El Nino .
hillybilly
Johnno on Mon 17 Aug 2009 - 18:59
Great to see you Rob thanks for your input.
Yeah Karl heres the latest BOM site updated today 17th August and we can see how much the positive sub-surface anomalies have weakened the past few weeks since July wouldn't suprise me to see this El Nino finished before even the end of year this isn't how things normally pan out in a traditional El Nino August. Love to hear your thoughts DJ?
http://www.bom.gov.au/bmrc/ocean/result ... 09/Aug.gif
And here it is looking it from another angle at 150 metres sub-surface level and as you can see ssts are almost back to Neutral East of about 160W along the Equator back to South America with the warmest Ssts now laying West & North of there
http://www.bom.gov.au/bmrc/ocean/result ... 09/Aug.gif
Starting to look messy and very disorgainsed to me.
Johnno
Re: ENSO & IOD
hillybilly on Wed 19 Aug 2009 - 20:43
Latest BoM outlook was updated today http://www.bom.gov.au/climate/enso/ . The current event is shaping up as very messy - the waters around northern Australia are staying very warm (when they should be cooling) and the Indian Ocean dipole is refusing to go positive. This would suggests that the rainfall response for OZ will be tempered somewhat by local moisture sources.
It's possible the odd behaviour of the SOI reflects the record heatwave which has lead to lower pressures in the north as the spring heat lows comes a month early..
hillybilly
Re: ENSO & IOD
Johnno on Tue 25 Aug 2009 - 13:45
Johnno wrote:
It wouldn't suprise me if parts of NSW and Southern/SE Qld end up with a record dry in some areas for the last 6 months of the year there (July-December) mother nature works in funny ways and after the incredible wet up there the 1st 6 months this year and the past 2 years in general I kind of expect this to happen now if July is anything to go by after being so dry up there this month(rainless in some areas even for July standards thats very poor considering Brisbanes & other places up there averages are actually bit wetter than Melbourne for July) I expect this pattern to continue the coming months up there with the dry extending right into Victoria with the odd brief interuption of wet spells for Coastal areas of Victoria. Anyway thats my 2c worth and how I see things for the coming months feel free to shoot me down in flames
Well still 4 months to go til the end of the year but I made that comment over a month ago and since then thats exactly how its been happening we have had some OK or SPORATIC rain down here in Victoria as a whole since that comment so far but record HEAT & with it record DRY has started in Northern NSW and Qld as I predicted back in July and I expect this to continue well into Spring up there and see records broken in both the Dry side and temp side of things in the coming months (Its already been happening).
Johnno
Re: ENSO & IOD
hillybilly on Wed 26 Aug 2009 - 20:56
BTW looks like the stop-start El Nino is now back on. There has been a very strong westerly wind burst move across the Pacific with a rapid warming of surface and subsurface waters. This will probably be the last kick the system needs to flip into a full blown El Nino (as has been predicted by the models all year).
The weather over OZ is actually pretty El Nino like - though perhaps the westerlies are a little further north than usual (which is why Tas/Vic/southern SA are doing OK). Hopefully the westerlies continue....
hillybilly
Re: ENSO & IOD
Johnno on Mon 31 Aug 2009 - 18:23
Winter 2009 Deciles
http://www.bom.gov.au/cgi-bin/silo/rain ... ime=latest
August 2009 Deciles
http://www.bom.gov.au/cgi-bin/silo/rain ... ime=latest
Lucky Tassie!!! And El Nino starting to take hold in the Eastern states mainly NSW and Qld.
Johnno
Re: ENSO & IOD
Karl Lijnders on Mon 31 Aug 2009 - 19:45
http://www.bom.gov.au/cgi-bin/silo/rain ... ime=latest
Guess that puts it into perspective!!!.
Karl Lijnders
Re: ENSO & IOD
droughtbreaker on Tue 1 Sep 2009 - 0:30
The decile maps for winter and August are a good graphical description of just how dominant NW to W winds have been over the past 3 months with areas in lee of the ranges in VIC below average yet again thanks to the west central rain shadow and almost all of Tas above or well above average, basically the more vigorous the westerlies the higher the rainfall for Tas, particularly the western half of that state.
El Nino getting organised now and ready to unleash on us later into Spring. The good August rains (and likely to continue through the first half of September) are a godsend given the outlook for the second half of spring would be a bit grim at this stage. Hopefully it can be a weak and short lived El Nino this time. Good to see the atmosphere hasn't really responded that much yet with SOI figures remaining neutral..
droughtbreaker
Re: ENSO & IOD
hillybilly on Fri 9 Oct 2009 - 21:00
Reflecting the El Nino September 2009 has come out as the hottest September on record on the earth's surface according to NASA GIS.
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts.txt
2009 is now likely to be the second warmest (if not warmest) on record. With an El Nino 2010 is likely to be even hotter..
hillybilly
Re: ENSO & IOD
droughtbreaker on Fri 9 Oct 2009 - 21:24
Makes us all the more fortunate to have had such cool and wet weather for a prolonged period in the middle of one of the warmest periods for the globe..
droughtbreaker
Re: ENSO & IOD
Karl Lijnders on Fri 9 Oct 2009 - 22:21
.Well we certainly helped at the start of the year, now the rest of the planet can have a turn... .
Karl Lijnders
Re: ENSO & IOD
David on Sat 10 Oct 2009 - 11:10
Recent rainfall across southeastern Australia gives further proof that ENSO itself has little effect on us.
SST are warming up again across northern Australia after a brief cool down although we are moving into the time of the year where the northern SST effect is reduced..
David
Re: ENSO & IOD
hillybilly on Sun 11 Oct 2009 - 8:43
David ENSO has a decent impact on us - but it tends to operate through the Indian Ocean which usually, but not always, follows the lead of ENSO. The last two spring we had a +ve Indian Ocean dipole (despite a weak La Nina) which is at least a partial explanation for the dismal rainfall despite La Nina. In contrast this year we have had a near zero Indian Ocean Dipole and rainfall has been pretty close to average.
If you look back through the history about every second El Nino has given "drought" to southeast Australia, so about every second one didn't. However, it has been a bit worse than that in recent years.....
1994 was a drought, 1997 was a drought in parts, 2002 was a terrible drought, 2006 was a terrible drought, 2009 has been OK in many areas..
hillybilly
Re: ENSO & IOD
droughtbreaker on Sun 11 Oct 2009 - 11:10
What we are seeing now is not a 'proper' El Nino. I don't think it has actually been declared as one yet, it hasn't met the criteria. Similar to the last La Nina which only very briefly met the criteria but even so I never remember it actually being formally declared although pretty sure it was a genuine La Nina.
A full blown El Nino, the concept that I have of it anyway, develops earlier in the year, around mid Autumn to Winter and lasts for a whole year or relatively close to that on average. The SOI clearly mirrors what is happening with the oceans and vice versa and there is reinforcing feedback between those two variables that keep the event developing and persisting. Eventually the IOD generally goes positive as anomalously cool water flows across Northern Aus from the western Pacific and into the eastern Indian Ocean. I think the mechanism that causes this is called the 'Indonesian throughflow'.
This just hasn't happened this year and I put it down to a weak and disorganised warm neutral SST pattern in the Pacific that just hasn't been able to evolve into an organised El Nino event. Of course we could still get one developing next year but with the cool phase PDO in place this should be less likely than at other times in the past decade or two.
Still this is just my amateur knowledge, I don't profess to know all that much about this but that's the way i interpret the situation atm..
droughtbreaker
Re: ENSO & IOD
droughtbreaker on Sun 11 Oct 2009 - 11:19
Looking at the latest SST anomalies I can see another solid influx of warmer water heading east-west across northern AUS towards the eastern Indian Ocean whilst, at the other end, there is a rather intense cold patch off the equatorial South American coast. Without wanting to be premature about things it looks like this warm neutral pattern is definitely on the way out just going from current indications.
No signs whatsoever that the 'tap will be turned off' over the next month or so at least. If anything we should continue to see good rainfall..
droughtbreaker
Re: ENSO & IOD
hillybilly on Mon 12 Oct 2009 - 21:04
What we are seeing now is not a 'proper' El Nino.
Unless things develop quickly, I suspect this event will be a non-event. It reminds me of the protracted warm Pacific Conditions which pretty much dominated from about 2001 to 2006 and is more global warming than "El Nino". The temperatures which have been seen in the central/eastern Pacific are certainly warm enough to be labeled "El Nino" but at the same time waters northern Australia has been very warm (also).
The big worry then is that if this build up of heat is not El Nino - then what happens when we actually get a full blown El Nino .
hillybilly
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Re: ENSO & IOD
Karl Lijnders on Mon 12 Oct 2009 - 23:27
Maybe enjoy the rain while it's here!!!.
Karl Lijnders
Re: ENSO & IOD
droughtbreaker on Tue 13 Oct 2009 - 19:30
Well, yes, when we look at the bigger picture it becomes more disturbing, in a way though warmer oceans can provide the source moisture for heavier than normal rain if everything else goes right but 'everything else' rarely does go right these days as we know.
I am enjoying this rain whilst it lasts, it is falling at the right time of year IMO, nothing worse than a dry spring, makes summer even drier. The wheat crops should do well this year and other agricultural products. Dairy industry would be loving the pasture growth. Gardens and forests/bushland can put on some decent growth to recover somewhat from the damage of previous years. Of course some people, particularly those ignorant ones in the media are claiming the 'drought is over' which is mind numbing stuff but any decent period of rainfall we get is something to rejoice these days..
droughtbreaker
Re: ENSO & IOD
Johnno on Tue 13 Oct 2009 - 21:14
Models have us going back to neutral (Cool) or even back to weak La nina by Winter/Spring next year so can't see us having another El Nino or warm phase next Winter and Spring for 2010 given this will peak in the next couple of months and wane out normally this is the expected when you get a Warm pacific 1 year it goes back to Neutral or Cool the other year Prime examples of this are 1997 then by Winter/Spring 98 it was La Nina.. 1994 then by Winter/Spring 95 was Neutral to Cool.. 2006 by Winter/Spring 2007 Moderate La Nina even 2002 it bounced back to smack bang Neutral by the Winter and Spring of 2003 so not sure why there is talk of another El Nino in 12 months time when nothing indicates this.
Johnno
Re: ENSO & IOD
Power Storm on Tue 13 Oct 2009 - 21:46
The thing I am most worried about, is that the El Nino that is supposedly developing now, stops our great rainfall that we have been seeing over the next few weeks or the next month, and causes temperatures to rise back to above normal. I would hate to see what the Summer bushfire season would be like after all this rain and growth. It does not take much for a dry wind and several hot days to make the new growth burn-ready these days..
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
Karl Lijnders on Wed 14 Oct 2009 - 13:30
True Jake however the conditions of last summer was under extreme la niña conditions. I think the summer will be somewhat normal.
One week at a time .
Karl Lijnders
Re: ENSO & IOD
hillybilly on Thu 15 Oct 2009 - 7:43
Jake the "great" rainfall will stop for you almost certainly as your have a pretty strong winter rainfall peak. Any summer rain that areas west of about Geelong get in summer is a bonus. I used to live out near Mt Gambier and from mid November onwards it would frequently turn very dry and not start raining again until mid March. You had to rely on the out of season cold outbreak or rather rare easterly dip.
I'm with you Karl - my gut feeling is that with close to neutral/marginal El Nino conditions we are more likely to get a fairly average summer down here. The BoM's climate model has rainfall for us pretty close to average for Nov->Dec (http://poama.bom.gov.au/experimental/po ... prcp_1.png) while day temperatures are also pretty close to avearge (http://poama.bom.gov.au/experimental/po ... fmax_1.png). Rest of OZ doesn't look so good with hot dry conditions more likely (which seems to bear out in recent weather).
Also interesting that for late Oct early Nov things are likely to turn dry down here. Not a good sign for continued runoff...
Turns out that Black Saturday and Black Friday (Vic's two hottest days) both occurred during La Nina years - the rainfall in northern Australia in La Nina events provides the tropospheric heating (via condensation/latent heating) for extremely high temperatures..
hillybilly
Re: ENSO & IOD
Bobman on Thu 15 Oct 2009 - 13:48
Don't forget that in January we had about 0.2mm rainfall in Melbourne and we had the 3-4 day heatwave, so things were very different.
September last year had the driest rainfall on record across most suburbs. Given the amount of rain now and how everything is still quite green, I very much doubt that everything is "tinder dry" as some are saying..
Bobman
Re: ENSO & IOD
Power Storm on Thu 15 Oct 2009 - 21:07
Thanks guys.
Not exactly on topic, but I thought I would post this here as well as in the fire weather section...
-------
From, http://www.bushfirecrc.com/news/release ... k0910.html
Victoria
Above normal fire potential is expected for all of Victoria; a result of a persistent long-term rainfall deficit over the state. Forested areas in the Dandenong Ranges, Otway Ranges, the Grampians, the Macedon–Bendigo corridor, East Gippsland, and the water catchments of Melbourne are areas of particular concern. In all regions an early start to the fire season is likely. While recent rainfall totals in many areas of the state have been about average, it is not expected to mitigate the longer-term drying in the state.
------------.
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
droughtbreaker on Thu 15 Oct 2009 - 22:59
I think you'll find that state and federal governments, local government, local and state fire authorities and any other organisations or groups associated with bushfire research etc. will always talk up the threat of bushfire regardless of likely conditions. This is basically to stir people into action to prepare themselves for the fire season because a lot of people become complacent. Almost every summer sees weather that is conducive to fire outbreaks and, at the very least, a few days that are severe. (eg. high 30s, gusty wind, very low RH%).
Personally I haven't heard anyone from the BOM, or anyone on here suggest that this summer will be any more severe than any other summer. There is no real indication at all that this year will be anything out of the ordinary. Very interesting to hear about the La Nina/severe heat outbreak link. I always suspected the extreme temps down here on 'Black Saturday' and other occasions in January also, were linked to the unusually intense and extreme monsoon season that the northern half of the country experienced. Indeed it seems the QLD flooding and SE heatwaves were linked and very intense monsoons up north lead to an outflow of extreme hot and dry air down here, I guess it also has something to do with all the tropical moisture getting locked into and used up by the intense monsoon trough leaving us with dessicated air and an extreme buildup of heat in the interior due to a lack of tropical airmass incursions below the tropical areas. Just my theory there though.
I actually reckon we will see more easterly winds this summer and a higher frequency of tropical moisture incursions leading to a better storm season for us and less heat buildup through the interior with generally more cloud building through there. Still I would be just guessing.
Certainly the remainder of October looks like a classic summer pattern to me arriving a couple of months early and is not encouraging at all given this system being a bit of a flop, basically means we have just a third or thereabouts of the monthly average here to date and much less through many other parts of the state. The good rainfall of August/September could soon become a distant memory. Hopefully though it breaks down again in November. Climate is all about variation and we have been due for a ridging, high dominating pattern for some time now..
droughtbreaker
Re: ENSO & IOD
windyrob on Sat 17 Oct 2009 - 8:25
This enso event is certainly a weird one. It seem that the northern hemisphere is in el nino but the southern hemisphere refuses to co-operate. I've noticed when SSt in the pacific near the tip of south america are cool high pressure tends to dominate and strengthen the humbolt current. When the SSts are warm there the Nino 1+2 regions tend to warm up. I also wonder if there's some 18 year lunar cycle that affects the humbolt current through tidal effects
For australian rainfall the current warm (-IOD) north west and cold south west SST's seems ideal. Highs are sitting off WA instead of over the south east and lows are forming over the north west and drifting through central aus towards us.
The highs also seem to form in the descending air of the monsoon trough. Last year the Monsoon sat over Aus for ages creating a constant ridge across australia that led to the horrendous heat build up and drought. The previous years bad weather seemed related to a trough off vanuatu causing a high to sit over the southeast. Personally i would like to see the MOJO go round nice and quickly rather than getting stuck in one spot like lately!.
windyrob
Re: ENSO & IOD
droughtbreaker on Sat 17 Oct 2009 - 12:00
Latest indicators are a bit worrying with a sudden swing to classic El Nino with the western Pacific cooled right down with solid negative SST anomalies and the long term SOI trends just getting into the negatives now. Also these cool anomalies are flowing through to the eastern Indian with a +ve IOD look about things. We see this rapid shift in conditions with the El Nino finally starting to have an impact and now suddenly we have a strong ridging setup with the highs over the SE of the continent and some rather persistent heat set to be dragged down almost on cue.
Hopefully now that we are transitioning out of spring and towards summer the relationship between ENSO indicators and our actual weather here will weaken as it usually does around December and January. Other factors still seem to be pointing towards the El Nino pattern breaking down into next year and hopefully it will be just in time for normal Autumn rains to commence..
droughtbreaker
Re: ENSO & IOD
Johnno on Sat 17 Oct 2009 - 17:40
Just wondering if you can clarify something DJ.. Is it true few months ago you said that in an El Nino Summer (In a weakening mode of course) that it isn't normally as hot down here due to more frequent SW winds so therefore not that hot? And La Nina Summers you can have blocks therefore more NE to N winds with more rain up the east coast and heatwaves down here? Think it might go again this way this Summer with perhaps a milder Summer? POAMA suggests normal average temps and rainfall does it? At least for December and January at the moment for down here.
Johnno
Re: ENSO & IOD
droughtbreaker on Sat 17 Oct 2009 - 20:50
hillybilly wrote:
First thing to remember is that global warming is changing everything - the source region for our heatwave (about 20S) is warming up rather quickly (http://www.bom.gov.au/cgi-bin/climate/c ... eriod=1970). It's a noise trend, but essentially now we have air that is frequently extremely hot ready to dive south.
You actually find that El Nino summers are usually "cooler than average" but have a small number of very dry very hot windy days. In contrast, La Nina summers are usually "warmer than average" but most usually lack very dry hot windy days. La Nina summers tend to have a lot of northeasterlies and El Nina summers tend to have a lot of southwesterlies. This is in the average - however - as I'll explain below...
As it turns out the two hottest spells in Victoria's history - 1939 and 2009 were both La Nina summers. These were both characterised by a extended block with little change in air mass. I suspect there is a bit of sting in the tail of the northeasterly pattern common in La Nina. The La Nina pattern means the summers are often very blocked and occasionally these blocks lead to the build up of extreme heat.
That's the post you were looking for John..
droughtbreaker
Re: ENSO & IOD
windyrob on Sun 18 Oct 2009 - 11:13
.Does anyone know what effect west pacific typhoons have on El nino's. On one hand they would seem to cause westerly wind bursts but on the other they represent low pressure and increased convection! I wonder if thats why el ninos get going during our autumn, before the northern typhoon season gets going?.
windyrob
Re: ENSO & IOD
Karl Lijnders on Mon 19 Oct 2009 - 11:59
We may be seeing the effect of classic el niño conditins but reserved for QLD and NSW which have both had dry and windy winters after very wet starts. The westerly may not be finished here yet with signs of it returning next week which is a sign that el niño is increasing. Good for rainfall here but shocking for fires in the eastern states..
Karl Lijnders
Karl Lijnders on Mon 12 Oct 2009 - 23:27
Maybe enjoy the rain while it's here!!!.
Karl Lijnders
Re: ENSO & IOD
droughtbreaker on Tue 13 Oct 2009 - 19:30
Well, yes, when we look at the bigger picture it becomes more disturbing, in a way though warmer oceans can provide the source moisture for heavier than normal rain if everything else goes right but 'everything else' rarely does go right these days as we know.
I am enjoying this rain whilst it lasts, it is falling at the right time of year IMO, nothing worse than a dry spring, makes summer even drier. The wheat crops should do well this year and other agricultural products. Dairy industry would be loving the pasture growth. Gardens and forests/bushland can put on some decent growth to recover somewhat from the damage of previous years. Of course some people, particularly those ignorant ones in the media are claiming the 'drought is over' which is mind numbing stuff but any decent period of rainfall we get is something to rejoice these days..
droughtbreaker
Re: ENSO & IOD
Johnno on Tue 13 Oct 2009 - 21:14
Models have us going back to neutral (Cool) or even back to weak La nina by Winter/Spring next year so can't see us having another El Nino or warm phase next Winter and Spring for 2010 given this will peak in the next couple of months and wane out normally this is the expected when you get a Warm pacific 1 year it goes back to Neutral or Cool the other year Prime examples of this are 1997 then by Winter/Spring 98 it was La Nina.. 1994 then by Winter/Spring 95 was Neutral to Cool.. 2006 by Winter/Spring 2007 Moderate La Nina even 2002 it bounced back to smack bang Neutral by the Winter and Spring of 2003 so not sure why there is talk of another El Nino in 12 months time when nothing indicates this.
Johnno
Re: ENSO & IOD
Power Storm on Tue 13 Oct 2009 - 21:46
The thing I am most worried about, is that the El Nino that is supposedly developing now, stops our great rainfall that we have been seeing over the next few weeks or the next month, and causes temperatures to rise back to above normal. I would hate to see what the Summer bushfire season would be like after all this rain and growth. It does not take much for a dry wind and several hot days to make the new growth burn-ready these days..
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
Karl Lijnders on Wed 14 Oct 2009 - 13:30
True Jake however the conditions of last summer was under extreme la niña conditions. I think the summer will be somewhat normal.
One week at a time .
Karl Lijnders
Re: ENSO & IOD
hillybilly on Thu 15 Oct 2009 - 7:43
Jake the "great" rainfall will stop for you almost certainly as your have a pretty strong winter rainfall peak. Any summer rain that areas west of about Geelong get in summer is a bonus. I used to live out near Mt Gambier and from mid November onwards it would frequently turn very dry and not start raining again until mid March. You had to rely on the out of season cold outbreak or rather rare easterly dip.
I'm with you Karl - my gut feeling is that with close to neutral/marginal El Nino conditions we are more likely to get a fairly average summer down here. The BoM's climate model has rainfall for us pretty close to average for Nov->Dec (http://poama.bom.gov.au/experimental/po ... prcp_1.png) while day temperatures are also pretty close to avearge (http://poama.bom.gov.au/experimental/po ... fmax_1.png). Rest of OZ doesn't look so good with hot dry conditions more likely (which seems to bear out in recent weather).
Also interesting that for late Oct early Nov things are likely to turn dry down here. Not a good sign for continued runoff...
Turns out that Black Saturday and Black Friday (Vic's two hottest days) both occurred during La Nina years - the rainfall in northern Australia in La Nina events provides the tropospheric heating (via condensation/latent heating) for extremely high temperatures..
hillybilly
Re: ENSO & IOD
Bobman on Thu 15 Oct 2009 - 13:48
Don't forget that in January we had about 0.2mm rainfall in Melbourne and we had the 3-4 day heatwave, so things were very different.
September last year had the driest rainfall on record across most suburbs. Given the amount of rain now and how everything is still quite green, I very much doubt that everything is "tinder dry" as some are saying..
Bobman
Re: ENSO & IOD
Power Storm on Thu 15 Oct 2009 - 21:07
Thanks guys.
Not exactly on topic, but I thought I would post this here as well as in the fire weather section...
-------
From, http://www.bushfirecrc.com/news/release ... k0910.html
Victoria
Above normal fire potential is expected for all of Victoria; a result of a persistent long-term rainfall deficit over the state. Forested areas in the Dandenong Ranges, Otway Ranges, the Grampians, the Macedon–Bendigo corridor, East Gippsland, and the water catchments of Melbourne are areas of particular concern. In all regions an early start to the fire season is likely. While recent rainfall totals in many areas of the state have been about average, it is not expected to mitigate the longer-term drying in the state.
------------.
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
droughtbreaker on Thu 15 Oct 2009 - 22:59
I think you'll find that state and federal governments, local government, local and state fire authorities and any other organisations or groups associated with bushfire research etc. will always talk up the threat of bushfire regardless of likely conditions. This is basically to stir people into action to prepare themselves for the fire season because a lot of people become complacent. Almost every summer sees weather that is conducive to fire outbreaks and, at the very least, a few days that are severe. (eg. high 30s, gusty wind, very low RH%).
Personally I haven't heard anyone from the BOM, or anyone on here suggest that this summer will be any more severe than any other summer. There is no real indication at all that this year will be anything out of the ordinary. Very interesting to hear about the La Nina/severe heat outbreak link. I always suspected the extreme temps down here on 'Black Saturday' and other occasions in January also, were linked to the unusually intense and extreme monsoon season that the northern half of the country experienced. Indeed it seems the QLD flooding and SE heatwaves were linked and very intense monsoons up north lead to an outflow of extreme hot and dry air down here, I guess it also has something to do with all the tropical moisture getting locked into and used up by the intense monsoon trough leaving us with dessicated air and an extreme buildup of heat in the interior due to a lack of tropical airmass incursions below the tropical areas. Just my theory there though.
I actually reckon we will see more easterly winds this summer and a higher frequency of tropical moisture incursions leading to a better storm season for us and less heat buildup through the interior with generally more cloud building through there. Still I would be just guessing.
Certainly the remainder of October looks like a classic summer pattern to me arriving a couple of months early and is not encouraging at all given this system being a bit of a flop, basically means we have just a third or thereabouts of the monthly average here to date and much less through many other parts of the state. The good rainfall of August/September could soon become a distant memory. Hopefully though it breaks down again in November. Climate is all about variation and we have been due for a ridging, high dominating pattern for some time now..
droughtbreaker
Re: ENSO & IOD
windyrob on Sat 17 Oct 2009 - 8:25
This enso event is certainly a weird one. It seem that the northern hemisphere is in el nino but the southern hemisphere refuses to co-operate. I've noticed when SSt in the pacific near the tip of south america are cool high pressure tends to dominate and strengthen the humbolt current. When the SSts are warm there the Nino 1+2 regions tend to warm up. I also wonder if there's some 18 year lunar cycle that affects the humbolt current through tidal effects
For australian rainfall the current warm (-IOD) north west and cold south west SST's seems ideal. Highs are sitting off WA instead of over the south east and lows are forming over the north west and drifting through central aus towards us.
The highs also seem to form in the descending air of the monsoon trough. Last year the Monsoon sat over Aus for ages creating a constant ridge across australia that led to the horrendous heat build up and drought. The previous years bad weather seemed related to a trough off vanuatu causing a high to sit over the southeast. Personally i would like to see the MOJO go round nice and quickly rather than getting stuck in one spot like lately!.
windyrob
Re: ENSO & IOD
droughtbreaker on Sat 17 Oct 2009 - 12:00
Latest indicators are a bit worrying with a sudden swing to classic El Nino with the western Pacific cooled right down with solid negative SST anomalies and the long term SOI trends just getting into the negatives now. Also these cool anomalies are flowing through to the eastern Indian with a +ve IOD look about things. We see this rapid shift in conditions with the El Nino finally starting to have an impact and now suddenly we have a strong ridging setup with the highs over the SE of the continent and some rather persistent heat set to be dragged down almost on cue.
Hopefully now that we are transitioning out of spring and towards summer the relationship between ENSO indicators and our actual weather here will weaken as it usually does around December and January. Other factors still seem to be pointing towards the El Nino pattern breaking down into next year and hopefully it will be just in time for normal Autumn rains to commence..
droughtbreaker
Re: ENSO & IOD
Johnno on Sat 17 Oct 2009 - 17:40
Just wondering if you can clarify something DJ.. Is it true few months ago you said that in an El Nino Summer (In a weakening mode of course) that it isn't normally as hot down here due to more frequent SW winds so therefore not that hot? And La Nina Summers you can have blocks therefore more NE to N winds with more rain up the east coast and heatwaves down here? Think it might go again this way this Summer with perhaps a milder Summer? POAMA suggests normal average temps and rainfall does it? At least for December and January at the moment for down here.
Johnno
Re: ENSO & IOD
droughtbreaker on Sat 17 Oct 2009 - 20:50
hillybilly wrote:
First thing to remember is that global warming is changing everything - the source region for our heatwave (about 20S) is warming up rather quickly (http://www.bom.gov.au/cgi-bin/climate/c ... eriod=1970). It's a noise trend, but essentially now we have air that is frequently extremely hot ready to dive south.
You actually find that El Nino summers are usually "cooler than average" but have a small number of very dry very hot windy days. In contrast, La Nina summers are usually "warmer than average" but most usually lack very dry hot windy days. La Nina summers tend to have a lot of northeasterlies and El Nina summers tend to have a lot of southwesterlies. This is in the average - however - as I'll explain below...
As it turns out the two hottest spells in Victoria's history - 1939 and 2009 were both La Nina summers. These were both characterised by a extended block with little change in air mass. I suspect there is a bit of sting in the tail of the northeasterly pattern common in La Nina. The La Nina pattern means the summers are often very blocked and occasionally these blocks lead to the build up of extreme heat.
That's the post you were looking for John..
droughtbreaker
Re: ENSO & IOD
windyrob on Sun 18 Oct 2009 - 11:13
.Does anyone know what effect west pacific typhoons have on El nino's. On one hand they would seem to cause westerly wind bursts but on the other they represent low pressure and increased convection! I wonder if thats why el ninos get going during our autumn, before the northern typhoon season gets going?.
windyrob
Re: ENSO & IOD
Karl Lijnders on Mon 19 Oct 2009 - 11:59
We may be seeing the effect of classic el niño conditins but reserved for QLD and NSW which have both had dry and windy winters after very wet starts. The westerly may not be finished here yet with signs of it returning next week which is a sign that el niño is increasing. Good for rainfall here but shocking for fires in the eastern states..
Karl Lijnders
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Re: ENSO & IOD
hillybilly on Tue 20 Oct 2009 - 8:04
.Interesting that the SOI is falling fast (down to about -5) and the central Pacific has warmed rapidly due to strong westerly winds (http://www.pmel.noaa.gov/tao/jsdisplay/ ... y_ps32.gif). It certainly doesn't look like a normal El Nino pattern, but it is a shift more towards El Nino.
The worry is that we have seen a shift to drier conditions in the southeast which will continue through the remainder of spring. Usually during El Nino events things start to dry out in the southeast during spring - autumn/winter can be a mixed bag but by spring the dry almost always becomes established at some point. At this stage October could still be a shocker for Vic if we don't get another rain event.
Further north the dry conditions in NSW and QLD have been very typical El Nino..
hillybilly
Re: ENSO & IOD
Johnno on Tue 20 Oct 2009 - 13:57
NSW and Qld may get their share over the coming week if EC and GFS have anything to do with it DJ and October may end up being a wet month for alot of them up there but to be honest I'm not so sure it will develop as EC and GFS suggest as other models aren't really onboard.
Johnno
Re: ENSO & IOD
droughtbreaker on Tue 20 Oct 2009 - 19:17
That rainfall map is a bit misleading for up here, I guess due to a lack of reporting rainfall gauges. We have had 51mm here so far this month and that is actually 66% of the current October mean for my place with around 34 years of records. The last three Octobers have all seen rainfall less than 20mm (crazy ) so the average has actually gone down dramatically purely thanks to that, but still I'd say we are at least 57% of the monthly mean even if you disregard the last few years. I couldn't say, even if we don't get another drop of rain this month, that is has been a very dry month, just a standard dry month.
The main thing we need to remember is that systems can evolve and patterns can change very quickly. I'm sure there have been heaps of occasions where there have been extended dry spells in a month but one event at the end of the month makes up the numbers. Also November could still be wet even if the rest of October is rainless. I understand why everyone is so concerned, I'm concerned too by the latest pattern change but it is not at all unusual IMO..
droughtbreaker
Re: ENSO & IOD
hillybilly on Wed 21 Oct 2009 - 7:45
That rainfall map is a bit misleading for up here, I guess due to a lack of reporting rainfall gauges.
Andrew the map is against the 1961-1990 average which might explain the difference. It is also based on a 25km grid which will smooth out some detail, particularly where altitude has played a role. In the Dandenongs it's a mixed bag. The southern Dandenongs have had a shocking October - about 60mm - which is 50% of average. The area around Olinda has had close to 100mm which is about 80% of average so "almost" average.
The months rainfall has tended to be in shower bands/storms which have tended to form streets meaning some areas have been dumped on while near neighbours have missed out.
BTW I suspect Melbourne's Jan->Oct total could be a record low. The city has had a shocking shocking year.....
hillybilly
Re: ENSO & IOD
Johnno on Thu 22 Oct 2009 - 12:06
Tomorrow the BOM's 3 months rainfall outlook chances and temps are out predicting from November to January and going by history I would say be similar to what was forecasted in 2002 and 2006 (both El Ninos yrs similar ocean temps to now) for the November to January periods? Why do I say this? Going by history came across this....
Rainfall outlook 2002 Oct to Dec..
http://www.bom.gov.au/announcements/med ... 917R.shtml
Rainfall outlook 2006 Oct to Dec..
http://www.bom.gov.au/announcements/med ... 926R.shtml
Rainfall outlook 2009 Oct to Dec...
http://www.bom.gov.au/climate/ahead/arc ... 0922.shtml
Anyone else see an almost identical forecast? I certaintly do for most of Australia and especially Victoria... Almost a cut and paste job but I'm sure BOM have their reasons (Mainly El Nino)
Now heres tempertures for the same period October to December
2002.. http://www.bom.gov.au/announcements/med ... 917T.shtml
2006.. http://www.bom.gov.au/announcements/med ... 926T.shtml
2009..
http://www.bom.gov.au/climate/ahead/arc ... 0922.shtml
Once again pretty much mirror image hey!
Heres the rainfall chances now forecasted for November to January 2002/03 & 2006/07..
http://www.bom.gov.au/announcements/med ... 016R.shtml
http://www.bom.gov.au/announcements/med ... 026R.shtml
Once again another mirror image!
And Tempertures for the same period (Nov to Jan 2002/03 & 2006/07)
http://www.bom.gov.au/announcements/med ... 016T.shtml
http://www.bom.gov.au/announcements/med ... 026T.shtml
Very very similar once again.. Therefore My point and question is is it fair to say tomorrows outlook for Nov to Jan be any different comparing to the same period Nov to Jan of those years?? If I were a betting man I would say NO I expect a very similar rainfall and temp outlook again to those 2 years tomorrow and if not then I'm the one thats going to look like a stooge hey .
Johnno
Re: ENSO & IOD
Johnno on Fri 23 Oct 2009 - 12:48
Well I thought I might be eating humble pie today but it seems I am right on the mark.. The lastest 3 months rainfall and temps outlook is out for November 2009 to January 2010 and true to form they are an almost exact replica of Nov to Jan 2002/03 and 2006/07
Heres is rainfall outlook for 2002/03 Nov to Jan....
http://www.bom.gov.au/announcements/med ... 016R.shtml
2006/07 Nov to Jan...
http://www.bom.gov.au/announcements/med ... 026R.shtml
And now 2009/10 Nov to Jan...
http://www.bom.gov.au/climate/ahead/rain_ahead.shtml
The trend continues of the 3 years BOM progging the chances of rainfall very similar.
And temps outlook...
2002/03 Nov to Jan...
http://www.bom.gov.au/announcements/med ... 016T.shtml
2006/07 Nov to Jan...
http://www.bom.gov.au/announcements/med ... 026T.shtml
And now 2009/10 Nov to Jan..
http://www.bom.gov.au/climate/ahead/temps_ahead.shtml
Once again all very similar with only the Min temps of 2006/07 being slightly different the chances of SW WA.
Going by history then I would expect BOM next edition next month Dec to Feb (Summer) rainfall and temp outlook then for them to expect close to neutral temps and rainfall..
2002/03 Dec to Feb rainfall outlook...
http://www.bom.gov.au/announcements/med ... 115R.shtml
2006/07 Dec to Feb rainfall outlook...
http://www.bom.gov.au/announcements/med ... 123R.shtml
And temps..
2002/03 Dec to Feb temps outlook...
http://www.bom.gov.au/announcements/med ... 115T.shtml
2006/07 Dec to Feb temps outlook...
http://www.bom.gov.au/announcements/med ... 123T.shtml
Once again similar and I expect the next outlook late November for Summer to be little different to these.
John..
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 23 Oct 2009 - 20:54
Nice recap John
I think the next sequence of weather will be telling. The easterly winds are moving south over the northern part of Aus and we wave goodbye to the westerly winds. This forces high pressure south for a while as things settle into summer time and troughs and lows start forming over the interior. Transition times. It is how we evolve out of it that will be key.
I think there will be something towards the end of the run which may be 5-10mm but a more significant weather event may be about 21 days away as things start winding up into that summer pattern.
Interesting that the areas that are forecast to be drier than normal are going to enjoy some above average rainfall. El Nino is not what it used to be it seems .
Karl Lijnders
Re: ENSO & IOD
Power Storm on Fri 23 Oct 2009 - 22:02
I would like to also say thanks to John for putting that information up. I would have had no idea where to find past 3 month outlooks, and the stuff and info that you have posted is well worth looking at mate.. Thanks for posting that up, and what an interesting pattern the BoM seem to be following.... .
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
Johnno on Sun 25 Oct 2009 - 12:04
Thanks guys. Its in the media archives Jake on the top right hand corner on the home BOM page.
Came across this..
Bushfires in southeastern Australia linked to Indian Ocean Dipole events
http://www.agu.org/cgi-bin/highlights/h ... 9902&jc=gl.
Johnno
Re: ENSO & IOD
hillybilly on Wed 4 Nov 2009 - 7:18
Big surge in the El Nino indices in the last week. The SOI has fallen through the floor and the Pacific Ocean waters have risen sharply . Now certain that 2009 will go down as a significant El Nino year.
BTW why some might view this as "bad" it is actually a positive for the southeast in the longterm. This lurch into El Nino has been associated with the first cooling of the western Pacific which is the
first step in the break down of the El Nino. Over the next few months we should see the cooler water slowly erode the El Nino event so that moving into autumn/winter next year the El Nino should be over (http://www.bom.gov.au/climate/coupled_model/poama.shtml).
That said, we can anticipate below average rainfall across much of eastern Australia in the coming months..
hillybilly
Re: ENSO & IOD
hillybilly on Wed 4 Nov 2009 - 7:24
Just a quickie comment on the gloom about Vic rainfall. Below is the rainfall for the last 3 months
and here is the average winter/spring rainfall for historical El Nino years .
http://www.bom.gov.au/climate/ahead/eln ... spring.gif
We have actually done pretty well - all things considering. To get average to above average rainfall (generally from June to end October) has been very lucky - we've done well. That said, Jan/Feb and May were horribly dry and some have missed out - particularly those living near Melbourne CBD and surrounding areas.
Of course, a hot dry Nov/Dec could turn things bad quickly... and we do have the long long drought underlying everything..
hillybilly
Re: ENSO & IOD
Anthony Violi on Wed 4 Nov 2009 - 9:31
We have done extraordinarily well out here in the Yarra Valley, but that graph is a generalisation becuase there are some parts of Vic that havent had 20% of there average. And thats what makes this weather so puzzling. Certain pockets are receiving copious amounts of rain and others 50 kms away are recieving a fraction of that. In the past when we have had wet periods for several months the whole state does well but that has changed..
Anthony Violi
Re: ENSO & IOD
Johnno on Wed 4 Nov 2009 - 11:13
Yeah A Neutral IOD helped this Winter and early Spring when you would normally get a Positive IOD associated with an El Nino meaning Cool waters NW of Oz which didn't happen this year.
Word getting out into parts of the public/media that this El Nino is a "Modoki El Nino" know much about it guys? Apparently it's the opposite to a normal El nino developing which is warm water upwelling from the East and spreading west along the equator where this time it has been the other way round but its all El Nino to me. In 1 way I wouldn't mind this El Nino being strong now the stronger it gets the more the breakdown will be once its weakens which could cause all sorts of weather next Autumn it alsos increases the chances of La Nina later next year. We all remember what happend in 1998 after the big strong El Nino of 1997/98 don't we? Yess 98 was a very warm year nationwise and globally as the lag effect lingered from the El Nino but as the Strong El Nino broke down alot of Australia saw above average rainfall that year so it was a warm and wet year for most of the nation so I am hopeing for something similar next year..
Last edited by Johnno on Wed 4 Nov 2009 - 11:59; edited 1 time in total
Johnno
Re: ENSO & IOD
Johnno on Wed 4 Nov 2009 - 11:17
Also the SOI as DJ has stated has fallen rapidily last 3 to 4 weeks and is now -17 and still falling which is lower than the 2002/03 and 2006/07 events on any given month of those years. Would it be fair to say even as now this El Nino would be classified as a Moderate to Strong event? the ssts structure seems warmer now than the 2006/07 El Nino which was classified as moderate and the 2002/03 El Nino.
Johnno
Re: ENSO & IOD
The Watto on Wed 4 Nov 2009 - 14:19
So with this El Nino does it look like it will continue into Summer and start breaking down around April time?
Looking at the weather over the next week it looks like a sign of things to come over the next few months.
The Watto
hillybilly on Tue 20 Oct 2009 - 8:04
.Interesting that the SOI is falling fast (down to about -5) and the central Pacific has warmed rapidly due to strong westerly winds (http://www.pmel.noaa.gov/tao/jsdisplay/ ... y_ps32.gif). It certainly doesn't look like a normal El Nino pattern, but it is a shift more towards El Nino.
The worry is that we have seen a shift to drier conditions in the southeast which will continue through the remainder of spring. Usually during El Nino events things start to dry out in the southeast during spring - autumn/winter can be a mixed bag but by spring the dry almost always becomes established at some point. At this stage October could still be a shocker for Vic if we don't get another rain event.
Further north the dry conditions in NSW and QLD have been very typical El Nino..
hillybilly
Re: ENSO & IOD
Johnno on Tue 20 Oct 2009 - 13:57
NSW and Qld may get their share over the coming week if EC and GFS have anything to do with it DJ and October may end up being a wet month for alot of them up there but to be honest I'm not so sure it will develop as EC and GFS suggest as other models aren't really onboard.
Johnno
Re: ENSO & IOD
droughtbreaker on Tue 20 Oct 2009 - 19:17
That rainfall map is a bit misleading for up here, I guess due to a lack of reporting rainfall gauges. We have had 51mm here so far this month and that is actually 66% of the current October mean for my place with around 34 years of records. The last three Octobers have all seen rainfall less than 20mm (crazy ) so the average has actually gone down dramatically purely thanks to that, but still I'd say we are at least 57% of the monthly mean even if you disregard the last few years. I couldn't say, even if we don't get another drop of rain this month, that is has been a very dry month, just a standard dry month.
The main thing we need to remember is that systems can evolve and patterns can change very quickly. I'm sure there have been heaps of occasions where there have been extended dry spells in a month but one event at the end of the month makes up the numbers. Also November could still be wet even if the rest of October is rainless. I understand why everyone is so concerned, I'm concerned too by the latest pattern change but it is not at all unusual IMO..
droughtbreaker
Re: ENSO & IOD
hillybilly on Wed 21 Oct 2009 - 7:45
That rainfall map is a bit misleading for up here, I guess due to a lack of reporting rainfall gauges.
Andrew the map is against the 1961-1990 average which might explain the difference. It is also based on a 25km grid which will smooth out some detail, particularly where altitude has played a role. In the Dandenongs it's a mixed bag. The southern Dandenongs have had a shocking October - about 60mm - which is 50% of average. The area around Olinda has had close to 100mm which is about 80% of average so "almost" average.
The months rainfall has tended to be in shower bands/storms which have tended to form streets meaning some areas have been dumped on while near neighbours have missed out.
BTW I suspect Melbourne's Jan->Oct total could be a record low. The city has had a shocking shocking year.....
hillybilly
Re: ENSO & IOD
Johnno on Thu 22 Oct 2009 - 12:06
Tomorrow the BOM's 3 months rainfall outlook chances and temps are out predicting from November to January and going by history I would say be similar to what was forecasted in 2002 and 2006 (both El Ninos yrs similar ocean temps to now) for the November to January periods? Why do I say this? Going by history came across this....
Rainfall outlook 2002 Oct to Dec..
http://www.bom.gov.au/announcements/med ... 917R.shtml
Rainfall outlook 2006 Oct to Dec..
http://www.bom.gov.au/announcements/med ... 926R.shtml
Rainfall outlook 2009 Oct to Dec...
http://www.bom.gov.au/climate/ahead/arc ... 0922.shtml
Anyone else see an almost identical forecast? I certaintly do for most of Australia and especially Victoria... Almost a cut and paste job but I'm sure BOM have their reasons (Mainly El Nino)
Now heres tempertures for the same period October to December
2002.. http://www.bom.gov.au/announcements/med ... 917T.shtml
2006.. http://www.bom.gov.au/announcements/med ... 926T.shtml
2009..
http://www.bom.gov.au/climate/ahead/arc ... 0922.shtml
Once again pretty much mirror image hey!
Heres the rainfall chances now forecasted for November to January 2002/03 & 2006/07..
http://www.bom.gov.au/announcements/med ... 016R.shtml
http://www.bom.gov.au/announcements/med ... 026R.shtml
Once again another mirror image!
And Tempertures for the same period (Nov to Jan 2002/03 & 2006/07)
http://www.bom.gov.au/announcements/med ... 016T.shtml
http://www.bom.gov.au/announcements/med ... 026T.shtml
Very very similar once again.. Therefore My point and question is is it fair to say tomorrows outlook for Nov to Jan be any different comparing to the same period Nov to Jan of those years?? If I were a betting man I would say NO I expect a very similar rainfall and temp outlook again to those 2 years tomorrow and if not then I'm the one thats going to look like a stooge hey .
Johnno
Re: ENSO & IOD
Johnno on Fri 23 Oct 2009 - 12:48
Well I thought I might be eating humble pie today but it seems I am right on the mark.. The lastest 3 months rainfall and temps outlook is out for November 2009 to January 2010 and true to form they are an almost exact replica of Nov to Jan 2002/03 and 2006/07
Heres is rainfall outlook for 2002/03 Nov to Jan....
http://www.bom.gov.au/announcements/med ... 016R.shtml
2006/07 Nov to Jan...
http://www.bom.gov.au/announcements/med ... 026R.shtml
And now 2009/10 Nov to Jan...
http://www.bom.gov.au/climate/ahead/rain_ahead.shtml
The trend continues of the 3 years BOM progging the chances of rainfall very similar.
And temps outlook...
2002/03 Nov to Jan...
http://www.bom.gov.au/announcements/med ... 016T.shtml
2006/07 Nov to Jan...
http://www.bom.gov.au/announcements/med ... 026T.shtml
And now 2009/10 Nov to Jan..
http://www.bom.gov.au/climate/ahead/temps_ahead.shtml
Once again all very similar with only the Min temps of 2006/07 being slightly different the chances of SW WA.
Going by history then I would expect BOM next edition next month Dec to Feb (Summer) rainfall and temp outlook then for them to expect close to neutral temps and rainfall..
2002/03 Dec to Feb rainfall outlook...
http://www.bom.gov.au/announcements/med ... 115R.shtml
2006/07 Dec to Feb rainfall outlook...
http://www.bom.gov.au/announcements/med ... 123R.shtml
And temps..
2002/03 Dec to Feb temps outlook...
http://www.bom.gov.au/announcements/med ... 115T.shtml
2006/07 Dec to Feb temps outlook...
http://www.bom.gov.au/announcements/med ... 123T.shtml
Once again similar and I expect the next outlook late November for Summer to be little different to these.
John..
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 23 Oct 2009 - 20:54
Nice recap John
I think the next sequence of weather will be telling. The easterly winds are moving south over the northern part of Aus and we wave goodbye to the westerly winds. This forces high pressure south for a while as things settle into summer time and troughs and lows start forming over the interior. Transition times. It is how we evolve out of it that will be key.
I think there will be something towards the end of the run which may be 5-10mm but a more significant weather event may be about 21 days away as things start winding up into that summer pattern.
Interesting that the areas that are forecast to be drier than normal are going to enjoy some above average rainfall. El Nino is not what it used to be it seems .
Karl Lijnders
Re: ENSO & IOD
Power Storm on Fri 23 Oct 2009 - 22:02
I would like to also say thanks to John for putting that information up. I would have had no idea where to find past 3 month outlooks, and the stuff and info that you have posted is well worth looking at mate.. Thanks for posting that up, and what an interesting pattern the BoM seem to be following.... .
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
Johnno on Sun 25 Oct 2009 - 12:04
Thanks guys. Its in the media archives Jake on the top right hand corner on the home BOM page.
Came across this..
Bushfires in southeastern Australia linked to Indian Ocean Dipole events
http://www.agu.org/cgi-bin/highlights/h ... 9902&jc=gl.
Johnno
Re: ENSO & IOD
hillybilly on Wed 4 Nov 2009 - 7:18
Big surge in the El Nino indices in the last week. The SOI has fallen through the floor and the Pacific Ocean waters have risen sharply . Now certain that 2009 will go down as a significant El Nino year.
BTW why some might view this as "bad" it is actually a positive for the southeast in the longterm. This lurch into El Nino has been associated with the first cooling of the western Pacific which is the
first step in the break down of the El Nino. Over the next few months we should see the cooler water slowly erode the El Nino event so that moving into autumn/winter next year the El Nino should be over (http://www.bom.gov.au/climate/coupled_model/poama.shtml).
That said, we can anticipate below average rainfall across much of eastern Australia in the coming months..
hillybilly
Re: ENSO & IOD
hillybilly on Wed 4 Nov 2009 - 7:24
Just a quickie comment on the gloom about Vic rainfall. Below is the rainfall for the last 3 months
and here is the average winter/spring rainfall for historical El Nino years .
http://www.bom.gov.au/climate/ahead/eln ... spring.gif
We have actually done pretty well - all things considering. To get average to above average rainfall (generally from June to end October) has been very lucky - we've done well. That said, Jan/Feb and May were horribly dry and some have missed out - particularly those living near Melbourne CBD and surrounding areas.
Of course, a hot dry Nov/Dec could turn things bad quickly... and we do have the long long drought underlying everything..
hillybilly
Re: ENSO & IOD
Anthony Violi on Wed 4 Nov 2009 - 9:31
We have done extraordinarily well out here in the Yarra Valley, but that graph is a generalisation becuase there are some parts of Vic that havent had 20% of there average. And thats what makes this weather so puzzling. Certain pockets are receiving copious amounts of rain and others 50 kms away are recieving a fraction of that. In the past when we have had wet periods for several months the whole state does well but that has changed..
Anthony Violi
Re: ENSO & IOD
Johnno on Wed 4 Nov 2009 - 11:13
Yeah A Neutral IOD helped this Winter and early Spring when you would normally get a Positive IOD associated with an El Nino meaning Cool waters NW of Oz which didn't happen this year.
Word getting out into parts of the public/media that this El Nino is a "Modoki El Nino" know much about it guys? Apparently it's the opposite to a normal El nino developing which is warm water upwelling from the East and spreading west along the equator where this time it has been the other way round but its all El Nino to me. In 1 way I wouldn't mind this El Nino being strong now the stronger it gets the more the breakdown will be once its weakens which could cause all sorts of weather next Autumn it alsos increases the chances of La Nina later next year. We all remember what happend in 1998 after the big strong El Nino of 1997/98 don't we? Yess 98 was a very warm year nationwise and globally as the lag effect lingered from the El Nino but as the Strong El Nino broke down alot of Australia saw above average rainfall that year so it was a warm and wet year for most of the nation so I am hopeing for something similar next year..
Last edited by Johnno on Wed 4 Nov 2009 - 11:59; edited 1 time in total
Johnno
Re: ENSO & IOD
Johnno on Wed 4 Nov 2009 - 11:17
Also the SOI as DJ has stated has fallen rapidily last 3 to 4 weeks and is now -17 and still falling which is lower than the 2002/03 and 2006/07 events on any given month of those years. Would it be fair to say even as now this El Nino would be classified as a Moderate to Strong event? the ssts structure seems warmer now than the 2006/07 El Nino which was classified as moderate and the 2002/03 El Nino.
Johnno
Re: ENSO & IOD
The Watto on Wed 4 Nov 2009 - 14:19
So with this El Nino does it look like it will continue into Summer and start breaking down around April time?
Looking at the weather over the next week it looks like a sign of things to come over the next few months.
The Watto
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Re: ENSO & IOD
Power Storm on Wed 4 Nov 2009 - 17:05
Thats the biggest concern I have had about this Summer. The heat just dry's things out, it certainly looks like a warmer than average month or so ahead, many records to be broken no doubt. Even though some parts of Victoria have done really well, it does not take that much to turn it dry and bleak again, setting the state up for another major bushfire season. The soil below is still very dry, and it seems my area (bar the NW of the state) is the only parts of the state that have fire restrictions on currently! I still think we will have a good storm season right up till the end of Autumn from now (lets hope wet thunderstorms and not dry), but it does look like drier conditions developing.
Oh and John, I would say it would be classified as a strong El Nino now, despite its strange start..
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
hillybilly on Wed 4 Nov 2009 - 20:17
Watto - yes we would expect the El Nino to break down over summer into autumn. The breakdown can happen very quickly (such as in 2006) or can drag on into autumn. This is partly due to unpredictable weather - the 2006 break down was associated with a sustained surge in the trade winds.
Yeah A Neutral IOD helped this Winter and early Spring when you would normally get a Positive IOD associated with an El Nino meaning Cool waters NW of Oz which didn't happen this year.
Word getting out into parts of the public/media that this El Nino is a "Modoki El Nino" know much about it guys?
Johnno I think the IOD really saved our bacon this year in the south. The pattern of rainfall for winter to now has been pretty classical El Nino with a neutral IOD. This pattern sees dry conditions through QLD/NSW but tending towards average across the south. It could have been a truly horrible year for all if this hadn't happened (though some areas were not so lucky such as around Melbourne which has experienced a horribly dry year).
BTW RE Modoki a lot of climate scientists don't buy the "modoki" idea - and I'm one of them. I think El Nino events come in all flavours and it makes little sense to try to give them one of two names ("modoki" or "normal/non-modoki") - I liken it to trying to summarise every summer/winter/spring/autumn as being "normal" or "abnormal" - makes no sense - every one is different. There is no need to simplify the "system" as climate models do not care about simple patterns - they take the current state of the ocean/atmosphere system and predict forwards in time capturing the full complexity..
hillybilly
Re: ENSO & IOD
Johnno on Thu 5 Nov 2009 - 17:32
Yeah thats what I think DJ its all El Nino to me I think some people are getting to techincal with it.
NOAA Sub-surface anomalies past 3 months..
http://www.cpc.ncep.noaa.gov/products/a ... zteq.shtml.
Johnno
Re: ENSO & IOD
Johnno on Fri 6 Nov 2009 - 12:36
Ssts off the NW coast of Australia have really warmed up in the past week to become above average temp wise this may possibily be a good thing in the long run for us.
I have Noticed a pattern with El Nino years that ssts off the NW coast of WA begin to suddenly warm rapidily in Early November happend in both 2002 and 2006 only differance to this year though is since June/July ssts remained warmish up there only October it got cooler than normal where the other 2 years the were cooler than normal from Winter to end of October but once again right on Cue 1st Week of November a sudden warming up there, if it goes anything like the other 2 El nino years I expect this warming to slowly spread Eastwards through the North coast of NT and into Torres Straight and the Gulf of Carpentaria and eventually into the Coral Sea the next few months as the El Nino gradually begins to slowly breakdown
http://www.weatherzone.com.au/climate/i ... aus&c=ssta.
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 6 Nov 2009 - 21:23
Certainly seeing that Indian Ocean heating, impact the W Coast troughs over the early part of the season. This gives us a great deal of expectancy that things may not be so bad this summer for the region with more small to moderate rain events and classical thunderstorm outbreaks.
BTW keep an eye on moisture at both sides of the country. I expect this to fold over and come down in the northerly advection by mid to late next week and re-enforced again as a LWT of some magnitude works towards the region in 10-12 days time.
Very hot weather to come..
Karl Lijnders
Re: ENSO & IOD
The Watto on Sun 15 Nov 2009 - 11:36
Hi Guys, I was wandering if any of you could make it clearer on the impact this El Nino is likely to have on South Australia between now and March. I apologise for my limited knowledge on this subject but I was reading the latest round up on the BOM website and the following was noted in the "iN Brief" section
"Most leading international computer models surveyed by the Bureau predict that El Niño conditions will persist throughout the southern hemisphere summer".
Correct me if I am wrong but I think that the last 2-3 El Ninos have peaked around December and broken down around Jan and Feb with good rainfalls. But is this El Nino, judging by the above comment, not likely to break down til around March time, so in my eyes that looks like it could be a summer of low rainfall and above av temps again, which would be devestating!
Any info appreaciated on this
Cheers, Michael.
The Watto
Re: ENSO & IOD
Johnno Yesterday at 15:21
Well Watto looks like the lastest BOM 3 month outlook updated today for Summer (Dec-Feb) are going for a Neutral Summer interms of rainfall if anything mabye slightly more chance of being wetter than normal through Central, Western and NW Vic & South Australia (50-60% chance)
Also the BOM have pulled back on being a hotter than normal Summer with more average temps more likely expected and theres a good chance the Minimums may be below average as well.. Anyway here are the maps updated today..
http://www.bom.gov.au/climate/ahead/rain.seaus.shtml
http://www.bom.gov.au/climate/ahead/temp.seaus.shtml
This does not mean we will not get anymore heatwaves this Summer but it may be more of a normal Summer and perhaps we won't get too many more and not as lengthy as intense thats the way I read it.
This doesn't suprise me as BOM had preety much the same maps in both years 2002/03 Summer and 2006/07 Summer interms of rainfall % chance and temps and both those El Nino Summers turned out to be close to what BOM thought so hopefully they are right again but time will tell.
Off the record been told by my mate Anthony/Malleefarmer that the box trees are flowering full on up in NW Victoria even more so than this time last year so mabye next year will be even better than this year up there interms of rainfall fingers crossed.
John..
Johnno
Re: ENSO & IOD
Karl Lijnders Yesterday at 16:19
Could be thanks to more intense rainfall systems like this weekend gone. It is more likely than not that we will get some more rainfall along the lines of what we have experienced.
The natural signs including the rain trees (silky oaks) flowering have delivered the past 4 years they have flowered. Before those years they went dormant..
Karl Lijnders
Re: ENSO & IOD
droughtbreaker Yesterday at 21:24
Silky oaks would be responding to the more humid conditions we have had recently. In QLD (where they are native) they respond to the hotter and more humid weather by flowering as it is an indication of the wet season ahead which is the best time for seed germination and success. Obviously down in VIC we do not have a summer wet season and the air is usually drier with lower rainfall, so if these trees are flowering well now it doesn't necessarily tell us anything about what will happen down the track, it is just telling us that we have had a sudden period of unseasonal sub-tropical type weather.
Jacarandas do the same thing, they are flowering now in Melbourne thanks to the early season heatwave and humid spell we have had and now the heavy rain. Most other years they start flowering a couple of weeks later, this year they are early.
The silky oaks aren't doing well here atm, mainly because they don't like cold climates and the drought combined with that has knocked them around. There are some around here in gardens that have grown fairly tall but they rarely look particularly healthy. In previous years where we have had better rainfall they have flowered a lot better.
I'm not sure about the box trees in the Mallee. (BTW is this 'Grey box' or some other species?) One thing I can't understand though is how plants and animals can predict what the weather is going to do, particularly long term. That is sort of getting into the supernatural IMO. Not disrespecting others' opinions or anything, but it just sort of sounds like magic, or mysticism that a living organism can know what the weather will do for an extended period of time into the future. The future doesn't exist yet and is subject to a huge number of variables and combinations of events happening that are changing all the time. We can predict what is more likely by studying ocean temps, various oscillations (ENSO, IOD, SAM etc.) but we can only give a statistical prediction like the BOM does, eg. 50% chance of above average rainfall. If a tree is flowering more prolifically than usual then that is a reaction to the current or recent climate and other related factors such as soil moisture and temperature etc, also the trees may simply be healthier this year than other years for whatever reason and therefore able to flower better..
droughtbreaker
Re: ENSO & IOD
Karl Lijnders Yesterday at 23:07
Thanks Andrew
The silky oaks look amazing here. They are so tall and doing really well. A few scraggly ones but there are plenty of 40m ones here doing really well and very orange at the moment. Just a note that it has been the last 4 years that we have had them bloom furiously and it has rained heavy in spring and could be due to increased humidity but they only bloomed with warmer wetter and drier air 2 weeks back so who knows. But it is interesting!!.
Karl Lijnders
Re: ENSO & IOD
Johnno Today at 9:43
Hi Andrew, I really believe the Silky oaks respond to whats going to happen not the heat and humidity as most of october was quite cool and dry alot of the time with low humidity it was only the last few days that we had high humidity and the thunderstorm outbreak but I kept a close eye on the trees right through October and they were heavily budding by Mid October for there flowering period in November (I even took a pic on my phone and sent it to Karl when they were in bud weeks before November started) there wasn't any heat around nor humidity or which to me shows there not responding to heat/humidity rather what will happen in the coming month.
Power Storm on Wed 4 Nov 2009 - 17:05
Thats the biggest concern I have had about this Summer. The heat just dry's things out, it certainly looks like a warmer than average month or so ahead, many records to be broken no doubt. Even though some parts of Victoria have done really well, it does not take that much to turn it dry and bleak again, setting the state up for another major bushfire season. The soil below is still very dry, and it seems my area (bar the NW of the state) is the only parts of the state that have fire restrictions on currently! I still think we will have a good storm season right up till the end of Autumn from now (lets hope wet thunderstorms and not dry), but it does look like drier conditions developing.
Oh and John, I would say it would be classified as a strong El Nino now, despite its strange start..
_________________
Jake.
The younger generation of weather.
Power Storm
Re: ENSO & IOD
hillybilly on Wed 4 Nov 2009 - 20:17
Watto - yes we would expect the El Nino to break down over summer into autumn. The breakdown can happen very quickly (such as in 2006) or can drag on into autumn. This is partly due to unpredictable weather - the 2006 break down was associated with a sustained surge in the trade winds.
Yeah A Neutral IOD helped this Winter and early Spring when you would normally get a Positive IOD associated with an El Nino meaning Cool waters NW of Oz which didn't happen this year.
Word getting out into parts of the public/media that this El Nino is a "Modoki El Nino" know much about it guys?
Johnno I think the IOD really saved our bacon this year in the south. The pattern of rainfall for winter to now has been pretty classical El Nino with a neutral IOD. This pattern sees dry conditions through QLD/NSW but tending towards average across the south. It could have been a truly horrible year for all if this hadn't happened (though some areas were not so lucky such as around Melbourne which has experienced a horribly dry year).
BTW RE Modoki a lot of climate scientists don't buy the "modoki" idea - and I'm one of them. I think El Nino events come in all flavours and it makes little sense to try to give them one of two names ("modoki" or "normal/non-modoki") - I liken it to trying to summarise every summer/winter/spring/autumn as being "normal" or "abnormal" - makes no sense - every one is different. There is no need to simplify the "system" as climate models do not care about simple patterns - they take the current state of the ocean/atmosphere system and predict forwards in time capturing the full complexity..
hillybilly
Re: ENSO & IOD
Johnno on Thu 5 Nov 2009 - 17:32
Yeah thats what I think DJ its all El Nino to me I think some people are getting to techincal with it.
NOAA Sub-surface anomalies past 3 months..
http://www.cpc.ncep.noaa.gov/products/a ... zteq.shtml.
Johnno
Re: ENSO & IOD
Johnno on Fri 6 Nov 2009 - 12:36
Ssts off the NW coast of Australia have really warmed up in the past week to become above average temp wise this may possibily be a good thing in the long run for us.
I have Noticed a pattern with El Nino years that ssts off the NW coast of WA begin to suddenly warm rapidily in Early November happend in both 2002 and 2006 only differance to this year though is since June/July ssts remained warmish up there only October it got cooler than normal where the other 2 years the were cooler than normal from Winter to end of October but once again right on Cue 1st Week of November a sudden warming up there, if it goes anything like the other 2 El nino years I expect this warming to slowly spread Eastwards through the North coast of NT and into Torres Straight and the Gulf of Carpentaria and eventually into the Coral Sea the next few months as the El Nino gradually begins to slowly breakdown
http://www.weatherzone.com.au/climate/i ... aus&c=ssta.
Johnno
Re: ENSO & IOD
Karl Lijnders on Fri 6 Nov 2009 - 21:23
Certainly seeing that Indian Ocean heating, impact the W Coast troughs over the early part of the season. This gives us a great deal of expectancy that things may not be so bad this summer for the region with more small to moderate rain events and classical thunderstorm outbreaks.
BTW keep an eye on moisture at both sides of the country. I expect this to fold over and come down in the northerly advection by mid to late next week and re-enforced again as a LWT of some magnitude works towards the region in 10-12 days time.
Very hot weather to come..
Karl Lijnders
Re: ENSO & IOD
The Watto on Sun 15 Nov 2009 - 11:36
Hi Guys, I was wandering if any of you could make it clearer on the impact this El Nino is likely to have on South Australia between now and March. I apologise for my limited knowledge on this subject but I was reading the latest round up on the BOM website and the following was noted in the "iN Brief" section
"Most leading international computer models surveyed by the Bureau predict that El Niño conditions will persist throughout the southern hemisphere summer".
Correct me if I am wrong but I think that the last 2-3 El Ninos have peaked around December and broken down around Jan and Feb with good rainfalls. But is this El Nino, judging by the above comment, not likely to break down til around March time, so in my eyes that looks like it could be a summer of low rainfall and above av temps again, which would be devestating!
Any info appreaciated on this
Cheers, Michael.
The Watto
Re: ENSO & IOD
Johnno Yesterday at 15:21
Well Watto looks like the lastest BOM 3 month outlook updated today for Summer (Dec-Feb) are going for a Neutral Summer interms of rainfall if anything mabye slightly more chance of being wetter than normal through Central, Western and NW Vic & South Australia (50-60% chance)
Also the BOM have pulled back on being a hotter than normal Summer with more average temps more likely expected and theres a good chance the Minimums may be below average as well.. Anyway here are the maps updated today..
http://www.bom.gov.au/climate/ahead/rain.seaus.shtml
http://www.bom.gov.au/climate/ahead/temp.seaus.shtml
This does not mean we will not get anymore heatwaves this Summer but it may be more of a normal Summer and perhaps we won't get too many more and not as lengthy as intense thats the way I read it.
This doesn't suprise me as BOM had preety much the same maps in both years 2002/03 Summer and 2006/07 Summer interms of rainfall % chance and temps and both those El Nino Summers turned out to be close to what BOM thought so hopefully they are right again but time will tell.
Off the record been told by my mate Anthony/Malleefarmer that the box trees are flowering full on up in NW Victoria even more so than this time last year so mabye next year will be even better than this year up there interms of rainfall fingers crossed.
John..
Johnno
Re: ENSO & IOD
Karl Lijnders Yesterday at 16:19
Could be thanks to more intense rainfall systems like this weekend gone. It is more likely than not that we will get some more rainfall along the lines of what we have experienced.
The natural signs including the rain trees (silky oaks) flowering have delivered the past 4 years they have flowered. Before those years they went dormant..
Karl Lijnders
Re: ENSO & IOD
droughtbreaker Yesterday at 21:24
Silky oaks would be responding to the more humid conditions we have had recently. In QLD (where they are native) they respond to the hotter and more humid weather by flowering as it is an indication of the wet season ahead which is the best time for seed germination and success. Obviously down in VIC we do not have a summer wet season and the air is usually drier with lower rainfall, so if these trees are flowering well now it doesn't necessarily tell us anything about what will happen down the track, it is just telling us that we have had a sudden period of unseasonal sub-tropical type weather.
Jacarandas do the same thing, they are flowering now in Melbourne thanks to the early season heatwave and humid spell we have had and now the heavy rain. Most other years they start flowering a couple of weeks later, this year they are early.
The silky oaks aren't doing well here atm, mainly because they don't like cold climates and the drought combined with that has knocked them around. There are some around here in gardens that have grown fairly tall but they rarely look particularly healthy. In previous years where we have had better rainfall they have flowered a lot better.
I'm not sure about the box trees in the Mallee. (BTW is this 'Grey box' or some other species?) One thing I can't understand though is how plants and animals can predict what the weather is going to do, particularly long term. That is sort of getting into the supernatural IMO. Not disrespecting others' opinions or anything, but it just sort of sounds like magic, or mysticism that a living organism can know what the weather will do for an extended period of time into the future. The future doesn't exist yet and is subject to a huge number of variables and combinations of events happening that are changing all the time. We can predict what is more likely by studying ocean temps, various oscillations (ENSO, IOD, SAM etc.) but we can only give a statistical prediction like the BOM does, eg. 50% chance of above average rainfall. If a tree is flowering more prolifically than usual then that is a reaction to the current or recent climate and other related factors such as soil moisture and temperature etc, also the trees may simply be healthier this year than other years for whatever reason and therefore able to flower better..
droughtbreaker
Re: ENSO & IOD
Karl Lijnders Yesterday at 23:07
Thanks Andrew
The silky oaks look amazing here. They are so tall and doing really well. A few scraggly ones but there are plenty of 40m ones here doing really well and very orange at the moment. Just a note that it has been the last 4 years that we have had them bloom furiously and it has rained heavy in spring and could be due to increased humidity but they only bloomed with warmer wetter and drier air 2 weeks back so who knows. But it is interesting!!.
Karl Lijnders
Re: ENSO & IOD
Johnno Today at 9:43
Hi Andrew, I really believe the Silky oaks respond to whats going to happen not the heat and humidity as most of october was quite cool and dry alot of the time with low humidity it was only the last few days that we had high humidity and the thunderstorm outbreak but I kept a close eye on the trees right through October and they were heavily budding by Mid October for there flowering period in November (I even took a pic on my phone and sent it to Karl when they were in bud weeks before November started) there wasn't any heat around nor humidity or which to me shows there not responding to heat/humidity rather what will happen in the coming month.
Follow us on Twitter @ AusWeatherForum
Re: ENSO & IOD
Looks like the +anomalies along the equator are starting to ease as El Nino condtions are slowly starting to weaken the SOI also remains close to Neutral at -5
Early days but looks like some of the global models are coming together in showing some sort of La Nina conditions developing sometime this year, Sintex has La Nina conditions developing Late Winter as does NASA but EC shows its as early as June-July, POAMA doesn't support this and still has Warm Neutral conditions until at least August but we have seen that model get it wrong so many times before and overestimate Warm conditions.
IOD also looks to be in our favour at this stage with all models that I have come across supporting another Winter of at least Neutral conditions to a possible weak Negative IOD.
Early days but looks like some of the global models are coming together in showing some sort of La Nina conditions developing sometime this year, Sintex has La Nina conditions developing Late Winter as does NASA but EC shows its as early as June-July, POAMA doesn't support this and still has Warm Neutral conditions until at least August but we have seen that model get it wrong so many times before and overestimate Warm conditions.
IOD also looks to be in our favour at this stage with all models that I have come across supporting another Winter of at least Neutral conditions to a possible weak Negative IOD.
-
Karl Lijnders
- Tornadic Supercell
- Reactions:
- Posts: 5771
- Joined: Sun Nov 22, 2009 11:17 pm
- Location: Knoxfield, Victoria
Re: ENSO & IOD
That could mean an increased risk of high temps next summer season.
Former Owner - The Australian Weather Forum. Email me anytime - weatherman1000@hotmail.com
-
Anthony Violi
- Supercell
- Reactions:
- Posts: 2652
- Joined: Mon Nov 23, 2009 9:03 pm
- Location: Lilydale
- Contact:
Re: ENSO & IOD
Found the right thread finally..
Nino temps are dropping nicely now.
http://www.cpc.ncep.noaa.gov/products/a ... ssta_c.gif
Nino temps are dropping nicely now.
http://www.cpc.ncep.noaa.gov/products/a ... ssta_c.gif
http://www.therealworldweatherforum.com" onclick="window.open(this.href);return false;
avweatherforecasts.com
avweatherforecasts.com