Looking towards substantial rainfall for SE Australia

[Karl Lijnders]

Odds are firiming of that low coming down in the next week and delivering widespread soaking rainfall. Potential for further flooding is moderate to high over inland VIC.

Also watch for a cold outbreak developing as a deepening cold core low forms east of Victoria coming this time next week.

[Proteous]

I'm scared, EC is progging about 8 inches of rain for here next week. I need to know what Petros thinks about this as this could be a genuine flooding event. It would appear that I may have sold my larger boat too early and will have no where to run. A long way out but am interested in what others are thinking about this?

[Petros]

Protee, I hope you are fit enough to man the pair of oars on the replacement Proteous ship (6' dingy with a pair of oars - I envisage) - and can hold your ground before you are swept out of the new entrance at Ocean Grange.

I also hope you dont meet up with the angry bloke you sold your ship to, as it, the mooring jetty's, and shaving Pt. etc. all flush out to sea in this, the last La Nina hurrah, officially heralds the end of the SW Aus 15 year drought for Gippsland.

Great to see you posting again Proteous!!

[Karl Lijnders]

This will not be the last of La Nina I can gaurentee that. We should have a few solid months of low pressure systems out east.

This particular system is sharing the rainfall around and I suspect by this time next week, most of southern VIC would have had 50-100mm with spot falls of 150mm along favourable areas on the windward slopes. But due to the apparent shifting from SW/S/SE then to E winds, we could see widespread uniform heavy falls along the dividing range.

Sunday/Monday could be rather convective across western and southern VIC while rain areas blanket the north and east.

[Petros]

I suspect most of us agree Karl, I for one agree with your prog's.

[stratospear]

All the good rainfall has gone out to sea...

The signs are ominous that high pressure will dominate our neck of the woods until late April or beyond. Not really anything substantial for a while...

[Lily]

http://www.news.com.au/breaking-news/we ... 6026013673

Wet, cool days ahead, Bureau of Meteorology says
From: AAP March 22, 2011 12:23PM


A WET few months are ahead for Queensland, with temperatures expected to be cooler than usual.

Higher than normal rainfall is also predicted for New South Wales between April and June.

But the Bureau of Meteorology's climate outlook for the three months to June says NSW, south-west Western Australia, South Australia, Victoria and Tasmania should enjoy a mild autumn and start to winter.

The data, released today, shows a wetter than normal season for eastern Australia, with south-east Queensland and north-east NSW 70 per cent likely to receive above-median rainfall.

A warm start to winter is predicted for the south-west and south-east of Australia, but the data shows chillier than normal days for parts of the tropics.

The weather bureau says there is up to a 75 per cent chance temperatures will be higher than usual across south-west Western Australia, south-east South Australia, southern NSW, Victoria and Tasmania.


In contrast, there is a 60 to 70 per cent chance of cooler than normal days across north-east Western Australia, most of the Northern Territory and south-east Queensland.

However, minimum night-time temperatures are predicted to rise in eastern Queensland, north-east NSW and south-west WA with minimum temperatures predicted to rise.

But cooler night-time minimum temperatures are expected in most of the Northern Territory, northern WA, most of South Australia and western Victoria.

The climate outlook has been produced using recent Pacific and Indian Ocean temperature patterns.

The bureau says the increased rain is a result of cool conditions in the central tropical Pacific Ocean associated with the current La Nina weather pattern, as well as warm conditions in the Indian Ocean.

[Meso]

Mild autumn and start to winter - I like it!

[Proteous]

Had over an inch of rain here today. Not bad for a for a system which appears to have had no interest anywhere else.

[Karl Lijnders]

In breaking weather VIC it has had plenty of interest LOL!

Falls of 400mm in Bega District is amazing!! Falls to 100mm occurring in the W Gippsland region.

[Petros]

Melbourne aside, the next substantial rain for SE Aus in now!

[stratospear]

Long range GFS is hinting at a major incursion of tropical moisture heading towards SE Australia from the NT in 10 or so days time. A troughy easterly setup in the lead up later next week, so one to watch.

[johnno]

Latest update from Elders April update which was done Yesterday..

The La Nina pattern continued to weaken through March as expected, although did not dissipate completely. The NINO3.4 index is one measure of La Nina and had returned to neutral conditions at the start of April. However, a strongly positive Southern Oscillation Index (SOI), along with anomalous sea surface temperature, indicated that northern and eastern Australia were still under the influence of this weakening pattern. The return to neutral conditions for the ENSO system this winter is almost unanimously agreed upon by the majority of ensemble models. Their is divergence among the long-range models on the outlook beyond winter, although most would favour neutral into Spring. The prospects of neutral conditions would be rated at 60% for spring and summer, with a 20% chance of La Nina and a 20% of a bounce back to El Nino.

The outlook for the Indian Ocean Dipole (IOD) is similar to that for the ENSO system above. At present, conditions are near neutral and are expected to remain near neutral through the first half of the austral winter. There are some indications of a return to slightly negative conditions later in winter and spring, due to warmer than usual equatorial waters near northwest WA. This would raise prospects of above average rainfall for southeastern Australia through this period in the form of northwest cloud bands.

The Southern Annular Mode (SAM) Index, which is a measure of the relative position of the polar front (and rain delivering cold fronts) for southern Australia has been moderately negative over the past two weeks, indicating we are now in a phase of increased frontal activity through southern Australia. This was seen in the first week of April with a front delivering Perth's first rainfall in over 60 days. Increased frontal activity (above the long term median) is expected over the next month due to this negative SAM figure.

Looking ahead, a continued weakening of the La Nina pattern should see rainfall totals drop off towards the median towards the start of winter but its positive affects on above average rainfall are expected to continue through the remainder of April and possibly May.

Anomalously warm waters continue around most of Australia and will have an impact upon the rainfall potential for the rest of autumn and into winter. SST's through the Coral Sea are returning to more normal levels but the Tasman Sea still has broad areas of SST anomalies in the 0.5-1.5 degree range, that would boost rainfall prospects for neighbouring parts of the mainland. Extreme warming can be seen through mid latitudes of the Indian Ocean near the WA coast, which combined with other factors (such as SAM) would point to a return to median, or above median rainfall this autumn and winter (after record low rainfall through the Southwest Land Division of WA in 2010).

[Ken]

Hi johnno,

Speaking of which, I made a post about the likely trends in ENSO with some graphs from models in the Climatology thread (under La Nina Chances) in case you're interested.

[crikey]

Lots of equatorial cloud being drawn South eastward from tropics in North West WA ocean.
Currently approaching WA coast from the western flank of Australia as seen on world satellite
http://www.metoffice.gov.uk/weather/satellite/" onclick="window.open(this.href);return false;
Date 12th April 2011 time 11.00pm
May extend the length of front currently approaching from the west and move across southern cross section of Australia? May beef it up a bit

[Petros]

For next 8 days in Vic, all I can see is a stock standard winter cold change sweeping through next Saturday?

[Petros]

Still nothing substantial on the horizon... a couple of cold changes to sweep by between Wed and next Saturday? Hopefully should leave a sunny day or two over easter.

[johnno]

Hi johnno,

Speaking of which, I made a post about the likely trends in ENSO with some graphs from models in the Climatology thread (under La Nina Chances) in case you're interested.

Thanks Ken had a look Interesting times ahead

[stratospear]

GFS is hinting at a very strong cold front with decent rainband and low pressure system on May 2. Over a week away but looks promising. EC onboard as well but positions low further south.

[droughtbreaker]

I notice the models stalling systems about a week into the run, in the case of EC atm, almost completely stopping them. I have actually noticed this quite a bit in recent months but I don't think we have had a really diabolical blocking pattern yet, and in the end the models come on board closer to the time and move systems through.

IMO the GFS scenario looks more likely than EC atm. It's a Tasman block but not a severe one like EC has. Either way the massive LWT that is building should cause some good rainfall over VIC in around 7 to 10 days time, particularly on the ranges. If GFS comes off there will be widespread showers with local hail and thunder later next weekend and some snow likely down to around 1000m (very rough guess).

It will be an interesting period to watch anyway.