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Re: Our new rainfall pattern in autumn in the southeast?

Posted: Wed May 19, 2010 5:32 pm
by johnno
In a few words... The airstream was to WSW/SW the coldish outbreaks that we have had over the past 5 weeks hence why the Eastern and SE suburbs have done well and Melbourne/City has missed out but the systems have been there just comes down to luck to what airstream you get behind fronts ie Westerly, South Westerly or Southerly ideal for "Melbourne"

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Wed May 19, 2010 6:59 pm
by Anthony Violi
As I posted earlier, Melbourne is now near Werribee for whatever reason, whilst out here our rainfall has increased markedly last 12 months. It now appears Melbournes rainfall is on par with western suburbs now. Would be interesting to see out here how much more rainfall we have had comparitive to last few years.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Wed May 19, 2010 8:13 pm
by Anthony Violi
Yes it sure would have, but as i said the last 12 months it has jumped markedly. It seems you must have been just on the wrong trajectory up in the dandenongs and most of the rainfall has been funnelled through the Eastern Burbs. Western Port area and peninsula has had a golden 6 weeks of late. Definitely noticed that the further West you go, the greater the deficiency.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Wed May 19, 2010 8:45 pm
by droughtbreaker
Anthony Violi wrote:Yes it sure would have, but as i said the last 12 months it has jumped markedly. It seems you must have been just on the wrong trajectory up in the dandenongs and most of the rainfall has been funnelled through the Eastern Burbs. Western Port area and peninsula has had a golden 6 weeks of late. Definitely noticed that the further West you go, the greater the deficiency.
Clearly not true Anthony.....

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It's actually been the other way around the last 12 months.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Wed May 19, 2010 8:58 pm
by johnno
Well lucky for you David the month isn't over yet and models such as EC and GFS and that are throwing in a decent rainband early next week so you may pick up abit more hopefully quite abit more to make your May figure look respectable.

Hobart has been dry of late but did we forget about last year how wet Tasmania was? Didn't Hobart have its wettest 7th year on record or something?

Andrew I think Anthony means the further West you go in Melbourne the drier it is or it has become not the state.

BTW I have had as much as the City David past 8 weeks and I'm further North west here in the North west suburbs and the nature strips are green here so not sure how they are starting to become yellow out towards the docklands

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Thu May 20, 2010 3:41 am
by Anthony Violi
Yes Andrew i meant in Melbourne. You know how the old theory was the CBD had double the rain of the western suburbs, then the Eastern had double the rain of the CBD? Thats what i meant, its now that the western suburbs and the CBD have much less than Eastern suburbs.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Thu May 20, 2010 9:08 pm
by Anthony Violi
I couldnt tell you what i had without going to the computer to check it David. But we have only had half of what the farm has had in coldstream.

Have you actually got out of the office and had a look around the yarra valley David? Warm is not a description that i would use for here, and most of Vic. The CBD and everywhere else are totally different atm. Yes, its been hit and miss but i cant see how it would be browning off.

I will take a photo this weekend and of my front and back lawn and show you how "warm" it must be. I have a forest outside that needs to be mowed, yet again.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Thu May 20, 2010 9:28 pm
by droughtbreaker
Soil moisture is relatively low currently, at least compared to what it should be at this time of year. Normally at this time of year the paddocks are starting to green up pretty much everywhere in southern VIC and around the ranges, haven't seen any signs of this happening this year and we are coming into June. Admittedly some of the wetter areas are green atm, our 1 acre here is green and the whole of the Mount Macedon area is green. I can imagine areas east of Melbourne and in South Gippsalnd are very green atm. All you have to do though is drive off the ranges here and it is back to yellow with only patchy green amongst it.

Sure we have a very well defined rain shadow that starts almost as soon as you leave the Macedon Ranges and continues right through to Melbourne so these areas where the grass is still mostly yellow are not wet areas and they are on stony basalt soils which are pretty ordinary for plant growth but the fact remains that all these areas are usually greening up by now and not this year.

I doubt that there has been much evaporation recently now that temps are consistently 20C or below across the state and solar radiation is low. Here we probably won't get above 15C now until August and most days should be high single figures to low teens through June. Still I understand what David is saying. Wouldn't read too much into nature strips yellowing in urban areas, could just be because people are walking over them for all we know.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Fri May 21, 2010 12:34 pm
by daviescr
Your grass should have stopped growing. The reason it hasn't is because it's been so warm and sunny.... in more normal years I put the mower away in April
I think that's a little simplistic really - typically grass will continue to grow above 6c. Light and temperature are not the only things involved in foliage growth either, any high school student will tell you this - Light;Temperature; Relative Humidity; CO2/Oxygen and and source of nutrients.
Yes it's been warm and sunny in the daytime, and definitely more humid, but what about the heavy dew we get when it's been nice and cool for the last 3 weeks?

I found an interesting image from NASA:
While it was used to show the extent of growth after the massive flood event for QLD and NSW, it clearly shows a positive-neutral anomoloy for much of VIC - certainly not any 'browning off'.

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Re: Our new rainfall pattern in autumn in the southeast?

Posted: Fri May 21, 2010 4:23 pm
by Anthony Violi
hillybilly wrote:
I will take a photo this weekend and of my front and back lawn and show you how "warm" it must be. I have a forest outside that needs to be mowed, yet again.
Your grass should have stopped growing. The reason it hasn't is because it's been so warm and sunny.

We're still cutting the lawn in Ferny Creek - in more normal years I put the mower away in April.
I want to see a grass mowing anomaly map David.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Fri May 21, 2010 7:27 pm
by droughtbreaker
Evergreen plants usually stop growing when the daily temperatures, (the average between the maximum and minimum temperatures) drop below 10C. For most parts of the state in the winter months this is the case but especially on the ranges, here the average daily temp for July is around 5.5C-6C. This isn't to say the grass dies and browns off during this time, all it means is that you stop having to mow the lawn and I find lawn grass tends to take on a more bluish hue. Daylight hours are already close to a minimum atm with 10 hour days and that will drop to closer to 9 & 1/2 hours around the solstice. Plants cannot sustain growth with such little sunlight. As we progress through winter we will find that days become cloudier. Melbourne averages just 3.6 hrs of sunshine a day in June and 3.9 hrs this month. Melbourne is currently running 2hrs a day above average for sunshine for this month, no surprises then that is has been a dry one for a lot of the state.

A lot of the positive anomalies in the NDVI index would mainly be growth in the forests and not just grass growth. Grass growth certainly would be one element but there has been huge growth this year, both in the garden and the nearby forest. We planted a silver wattle up the front of our property about a year and a half ago and it has grown about 3m this year and has only stopped growing now. This particular species of tree is a notoriously quick grower but 3m is pushing the envelope.

I'll have to go out this weekend and see if there has been any greening of the paddocks around the place. I'm only home in the dark now during the week so there might have been some new growth in recent days. Western suburbs are starting to show a bit of greenery now. As I said in my previous post, it should be starting to green up by now.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Fri May 21, 2010 11:22 pm
by Anthony Violi
It was obviously a joke david...unless you have graphs to show how many times a lawn gets mowed on average per month.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Mon May 24, 2010 10:03 am
by Anthony Violi
This was my front lawn yesterday, before i attacked it with the lawnmower.

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We certainly dont have any issues out this way with rainfall, the most amazing thing is that there are so many isolated pockets this year that have had plenty or little.

278mm YTD. Coldstream has had over 350mm, and i think the belt through Knoxfield to Coldstream would have the highest. That belt is about 2 kms to our west here, it usually misses or just grazes us.

And my front lawn has looked like this all year since September which is truly remarkable. I think the big rain in March preserved it enough for the following dry spell we had.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Mon May 24, 2010 10:12 am
by Anthony Violi
No it hasnt. But the fact that it hasnt browned off is a good sign. I think everyones average for April - May would be running at roughly 50%. Except for the CBDesert.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Mon May 24, 2010 11:39 am
by Beatrix Kiddo
hillybilly wrote:Noticed today that the grass in Docklands along Wurrenjeri way has now turned yellow. It is only in damp spots/holes that the grass is still green.
Is the grass going dormant yellow/tan or drying out yellow? I have yellow/tan patchy grass around me due to the lack of sunlight and shading (winter). Certainly not a issue of soil moisture more so lack of sunlight.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Mon May 24, 2010 4:00 pm
by Beatrix Kiddo
Well it could also be a range of things from soil type, wind, grass variety, mowing height and fertilizing. Without knowing all this info for the area, it seems to be bucking the trend from the lawns i have seen from the NW through to the east. The browning i am seeing is the natural slow down of warm season turf. In exposed areas with poor soils, eg. the cbd, obviously drying would occur quicker but is not reflective of the majority of melbourne and surrounds.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Mon May 24, 2010 7:08 pm
by droughtbreaker
I would not read anything at all into a bit of yellowing in isolated patches of lawn in urban areas. Around North Melbourne it all looks pretty green to me, Flagstaff Gardens is green. It takes little moisture at this time of year to keep lawns green. We have an acre of lawn grass here (most of it is anyway) and it has been fully or mostly green since last winter. I find that even a few mornings of dew will cause substantial greening of the lawn. It is native grasses and pasture grass that tell the tale of soil moisture. Most of the paddocks around here are mostly yellow, the entire Macedon ranges area is pretty much green but not the surrounding farmland.

Soil moisture is not that crash hot at the moment but lawn grass will tell you nothing, particularly if we are talking small suburban plots or inner urban median strips.

Sitting on 321.5mm ytd here which is still above average despite a very ordinary stretch since early March.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Mon May 24, 2010 8:25 pm
by Beatrix Kiddo
Agree droughtbreaker there are far too many variables to consider grass colour in the cbd a guide to soil moisture. Same with suburban blocks, I am sure the sand belt are flat out keeping grass green anytime of year. I am comfortable betting that most public turf will be more yellow than green in July/august no matter how much rain falls. Weeds not included.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Tue May 25, 2010 6:46 pm
by Anthony Violi
I hope you call every month on the 12th David...the last 2 times has been a resounding success! Temp anomaly must have dropped, and Eastern and Northern Vic got a huge boost on their rainfall monthly totals, might even get close to the average for May.

Re: Our new rainfall pattern in autumn in the southeast?

Posted: Tue May 25, 2010 7:50 pm
by droughtbreaker
Well, I am not in the least bit surprised to see soil moisture at near record low levels. The rain we have had has come in heavy bursts with long stretches of sunny conditions and way above average temps. We need continuous moisture and low evaporation. the weather of the last couple of days is an example of weather that causes soil moisture to increase but we need a major rainfall episode, 50mm+ to really kick things off. The gardens and forest are very healthy but pasture grass remains as brown as it usually is in summer for most of the state.