Looking towards substantial rainfall for SE Australia

[adon]

Interesting signs on GFS for a large rain event offshore the NW WA coastline!! Hmmmmm

OK when and how do we go about moving it a few thousand Kms to the SE????

[Karl Lijnders]

Some signals that it will most likely dissolve into an upper feature and could bring some patchy falls this time next week but time will tell.

Otherwise the rainfall for southern areas remains the focus.

[Jake Smethurst]

Not sure on this upper feature. I have a feeling it wll most affect Queensland and parts of New South Wales. I am more interested in how quickly this high will move from Tuesday. It gets going quickly and signs are there that the next strong period of frontal activity will begin next Friday or Saturday.

[johnno]

From Elders updated Today

Through June and early July, all major climate drivers remained at near neutral levels. The Southern Oscillation Index (SOI) and NINO3.4 values remained at near neutral levels through this period. It was a similar story for the Indian Ocean Dipole, with near neutral values also persisting. The Antarctic Oscillation, or Southern Annular Mode(SAM) has recently moved towards neutral values and is expected to shift sharply negative through the middle of July. This increases the chances of cold, cloud and rainfall for southern states through to the end of the month. The polar long-wave charts display a distinct 4-wave pattern, which is a relatively mobile pattern, leading to regular frontal activity across southern Australia. This mobile pattern, in conjunction with the forecast SAM values, points to an increased likely of cold and wet conditions for southern capitals through the second half of July. Warmer than usual sea surface temperatures (SST) along the west coast of Western Australia are also going to play a role in providing evaporation and moisture for passing cold fronts through the remainder of July, boosting prospects of near median rainfall for southern states. These warm anomalies through the mid-latitudes of the Indian Ocean are becoming less pronounced however and developing cool anomalies around the north coast of Australia are pointing towards a weak positive IOD event in late winter and early spring. A positive IOD is correlated with a reduction in rainfall for the southeastern states during late winter and spring. This is reflected in the model output, especially in September. For the east coast of Australia, we are moving into the driest time of year (August-September) and with no significant climate drivers, typical low rainfall amounts near the 40 year mean would be the most likely outcome. This is in stark contrast to the record breaking rainfall seen in Queensland through this period in 2010, which was induced by a negative IOD and strengthening La Nina pattern across the Pacific. For spring and summer, the outlook for the ENSO system is looking increasingly like being in a neutral phase, with the majority of model output remaining at near neutral values. In percentage terms, the most likely outcome for the spring and summer is for neutral ENSO conditions at 75%, weak La Nina conditions at 15% and 10% El Nino based on evaluation of all models and a weighting towards the best performing guidance. Without a strong signal from the ENSO system it is likely that we will see greater month-to-month variation in rainfall through late spring and summer. There are indications that the east coast will see a return of above median rainfall in November before returning to near or below median values through December and January. Wetter than usual conditions are then indicated at the back end of summer. For the southeastern states, there is an overall trend towards below median rainfall through summer.

[adon]

Starting to get a little concerning about the lack of decent rain bearing systems coming through for the north of the state. The last one was a real dissapointment and we need some decent rain soon before it warms up. I see the SST have warmed of NW Australia now so hopefully we get get a cutoff coming through for us soon.

[crikey]

The south coast of NSW has been light on rain. But looks like there about to make up for it in one hit, according to this article

Extract
The South Coast of New South Wales is getting its first decent rain in more than a month, a period in which less than a millimetre had been recorded.....
...
By the weekend most of the region will have exceeded their monthly average. Most can expect another 50 to 100mm....

http://www.weatherzone.com.au/news/parc ... rain/18094" onclick="window.open(this.href);return false;

Could that happen in the NWest of Vic as well. How would those totals affect farming in Birchip?

I heard the Jane Bunn on Bendigo TV mention they are expecting a low from the North west?? ijn the near future. I suppose that's progged in the models??

[adon]

Crikey we really only need say 25-30mm in one rain to be fine. We have not had a rain over about 15mm since Jan. Having a massive heap of rain in one go would not do as much good as most of it would run off or just sit on the surface and flood young crops. Also need a decent rain while it's cold to help with the mice. A good wet, cold week can start off diseases in the little buggers.

[Petros]

Adon - that post was a bit introspective? - when a major rainfall event is unfolding in the context of this thread?

BOM has a flood watch for all SE Vic rivers from Latrobe R through to the Genoa for next 3 days. How often to we see that!!

[droughtbreaker]

It's funny. I was up in Coffs Harbour and came over via Armidale and Dorrigo and they had a deluge of 400mm-500mm from an ECL about a month prior and a follow up of 50mm two weeks later and I swear, other than significant damage to a few roads up there and the odd landslip, there was absolutely no sign of it. The ground was dry underfoot, even in the rainforest up on the plateau and the surrounding paddocks were mostly brown.

Having seen this I can agree with Adon to some extent that big falls all in one hit do not necessarily have lasting effect as opposed to frequent solid falls over time. Sure you get damaging floods that cause mayhem in the week or so after the event but if you don't get frequent follow up the soil will quickly dry out as the weather warms through spring and into summer, assuming that we won't get another spring/summer period like last season. This winter has been generally below average rainfall wise for VIC, and for many of us Autumn wasn't much to write home about either.

The westerly belt has been almost non existent so far this winter and adds to the trend we have been seeing in recent times for less frequent and weaker winter cold fronts.

This upcoming system though is vital for Gippsland and Melbourne's main catchment area as these areas rely on occasional ECLs for a considerable percentage of their annual rainfall, and when they fail they are in trouble, so it is excellent news to see this system is on the way.

[adon]

Adon - that post was a bit introspective? - when a major rainfall event is unfolding in the context of this thread?

BOM has a flood watch for all SE Vic rivers from Latrobe R through to the Genoa for next 3 days. How often to we see that!!

Petros no doubt this would be good for you, think you have been in the same boat as me (looking for rain while other are doing well). This event will not effect us at all apart from a wind from the south. No rain from it so therefore I am looking for the next chance. This "event" was over for me yesterday morning and it failed to deliver at all really.

[Petros]

Thanks DB/Adon.

My point is this (jeez, I sound like K Rudd), this thread isnt about Maffra's nor Oyens rain prospects, it about well, what the title states. Aust's SE from Adelaide through Canberra to Sydney??

[Karl Lijnders]

I think it is for the whole of SE Australia. This event is perfect this thread as it is swamping the whole region.

Petros, some fantastic weather out there this week.

Things turning more westerly over the coming few weeks so back to wetter weather in the west and drier in the far east.

[Ken]

Also of note are moderate probabilities of milder than normal temps starting to spread across southern parts of the continent around the end of this month and first week of next month, ahead of lowering pressures to the west of VIC. The warm anomalies look stronger around SA though.

[crikey]

It was 20 deg in Dunolly ( west Nth central VIC) today. T shirt day. Sunny warm.
In fact l was thinking. We had an early winter/autumn and l reckon we will have an early spring and summer.( just based on the feel of outside today)
Early summers usually lead to some very high temps over the summer period. As for rain, thinking average to below for the rest of the year, based solely on the fact we have pretty much had our years supply in Jan/Feb.
Statistically speaking, l reckon we will tend/lean toward BELOW AVERAGE rain for much of VIC for the rest of 2011
Love to be wrong!!!
We will need about 20mm+ to reach average for Maryborough within the next week. The low approaching from the west may deliver?
EDIT The BOM wind forecast map shows the next low pressure cell is on VIC western border saturday night 10pm .Is some body starting a new thread?

[Petethemoskeet]

I'm tending to lean the other way with the possiblity of a moderate to strong La Nina coupled with a negative IOD developing late spring.
IMO this could lead to a repeat of last summer/early autumns rain with floods in the usual places again.Could end up being worse than last
year because most of the dams are close to or fall.

[Geoff]

Yes me too, I've just done a few searches on the relevant latest info re; IOD and La Nina, and they seem to point (at the moment) on a possible repeat of last spring and summer's conditions, time alone will tell! We'll just have to deal with whatever nature throws at us when it happens.

[johnno]

IOD's only operate and have an effect in Australia/SE Australia May to October by November it has very minimal to a nothing effect over Australia thats when ENSO comes more into its own

[johnno]

Basically what I'm saying is the IOD whether Negative, Positive or Neutral only has an effect on us Winter through to early mid Spring & by November the IOD effect has well and truly finished

[Geoff]

EC and GFS both hinting at a strong westerly regime starting around beginning of August, could mean good rainfall for many. How do you usually fare over your side of the CBD in a westerly set up Johnno?

[droughtbreaker]

Yeah, good to see the models agreeing on a return to the normal winter pattern in around a week's time, i.e. westerlies and periodic fast moving LWT with strong fronts with the high ridge up around Brisbane where it should be.

I haven't been following the IOD situation much and just keeping in touch with the ENSO situation, but this winter has played out like a +ve IOD scenario with a lack of moisture feeding down from the tropics and very little in the way of NW cloud bands. Coastal and southern areas have probably been helped somewhat by the crazy meridional pattern which has cut us off from the inland a bit and allowed rain to form from other directions and sources rather than non stop rain shadow scenarios. I guess this bizarre disrupted pattern has also led to the lack of NW moisture.

It hasn't been a help for most of inland VIC on and north of the ranges though where most of the rain in June and July comes from northerly winds ahead of strong fronts and lows with moisture feeding in from the tropical NW. Most of VIC has had a very ordinary winter after a pretty lacklustre Autumn as well. The extreme rainfall from last Spring to early Autumn has made this autumn/winter dry spell much less of an issue. Dams are still filling and the soil moisture is still good.

If we can return to some normal winter/spring conditions with average rainfall we will be right back on track.