Topic: South East Australia Low : 20 - 24 March 2011

[Aarran Harvey]

Been looking at the the sypnotic predictions for the next week and its showing a low pressure system developing over New South Wales on Sunday then moving south and persisting over Victoria till about Wednesday night to Thursday morning. Forecast is for patchy rain on monday. Areas of rain on Tuesday. Areas of rain on Wednesday and isolated showers on Thursday. Sypnotic predictions show the low intensifying late tuesday into wednesday with central pressure dropping to about 990 hpa. Should be interesting to see how much rain there is over Victoria during this event.

[Michael Bath]

Hi Aarran,

Yeah it's an interesting weather event that's been showing up on the models for several days. Some runs have a strong east coast low, the next a weaker, broader system. Parts of VIC, TAS and NSW look set to cop some decent falls out of it. The low have been meandering around the country for quite some time. I think it started in the Gulf and crossed the southern half of NT into eastern WA before its forecast eastward jog this weekend.

[Aarran Harvey]

Whats got my attention though is how long its persisting over Victoria and Tasmania. Reminds me of 2nd and 3rd of February 2005 when Melbourne copped over 150 mm. That low was stationary for about 24 hours and this low looks like it will dominate Victoria andTasmania for a few days. I wonder if were in for a repeat ?

[Aarran Harvey]

I was just looking at the interactive wave forecast maps and its showing high levels of humidity over Victoria and Tasmania from Monday evening to Thursday evening. Mondays forecast of patchy rain has been changed to areas of rain. Looks like we can expect high amounts of rainfall from this event

[Jimmy Deguara]

Here in Schofields, we received 46.6mm of rain which is the highest rainfall for some time (recorded on the 20th March). Some coastal suburbs received well over 100mm.

Regards,

Jimmy Deguara

[Michael Bath]

Yes, finally some decent rain along the Central NSW coast though the Hunter has missed again. The BoM was rather slow in issuing the severe weather warnings for flash flooding.

Highest 24 hour fall in the Sydney basin appears to be 175mm at Turramurra.

At this the developing system is likely to focus the heaviest falls on Tasmania - we will see...

[pingtang]

Some very heavy falls at times down this way as well. My parents who live in the northern outskirts of Nowra recorded 110mms to 9am this morning.Thats opposed to 57mms at Nowra AWS, which is 12kms to their Southwest.And we've had another 25mms since then, with almost all of that falling in one really heavy shower just before midday. Many parts of the Illawarra recorded falls between 100-125mms to 9am,and i'd imagine the usual places such as Robertson could be close to 200mms.

[Aarran Harvey]

Sounds like you guys copped a nice downpour up there. BOM has issued flood watches for North East Victoria. Goulborn and Broken basins. Campaspe Loddon Avoca and Wimmera basins and Glenelg and Hopkins basins. Thunderstorms are also forecast tonight and tommorow. Im sitting here at the dental hospital and i can see some decent convection over the Western suburbs. Looks like we might have a nice show tonight. Hope i get my tooth checked quickly so i can get out and enjoy it

[Michael Bath]

Flood situation easing on South Coast
Douglas Fenton, Tuesday March 22, 2011 - 15:08 EDT
A low pressure system lingering along the NSW coast has brought yet more heavy rain.

In the 24 hours to 9am on Tuesday the Illawarra and South Coast were bombarded by downpours that would normally be reserved for the tropics.

The Illawarra received a daily total of 249mm to 9am today and that is their heaviest in 19 years.

The South Coast had scattered heavy falls of between 100-400 mm. Mount Darragh picked up 398 mm to 9am which would be classed as torrential even for the tropics and is more than 250mm above any daily total there in at least the past 4 years.

This heavy rain on the South Coast led to major flooding on the Bega River this morning.

This rain has now eased thanks to the southward movement of the low.

The heaviest rain is about eastern Victoria today which is also generally easing as it makes its way to Tasmania tonight.


- Weatherzone

Tasmania goes tropical
Douglas Fenton, Thursday March 24, 2011 - 12:38 EDT
Tasmania's east and north coasts have been inundated with the heaviest rain in up to 49 years.

Northeast Tasmania has received scattered falls of 100-300 mm in the 24 hours to 9am on Thursday, thanks to a deep low pressure system moving over the state.

Gray picked up a tropical like downpour of 327mm to 9am today, which is the highest daily rain since at least 1998. This comes after a previous daily total of 125mm, bringing the 48 hour rain total close to half a metre.

Pyengana got 200mm to 9am the highest on record since 1962 and St Marys received 173mm, the highest for March since 1974.

This low pressure system has now brought flooding rain to coastal NSW, eastern and Central VIC and now on to Tasmania. The South Esk and St Pauls Rivers have exceeded their major flood levels from Wednesday.

The low will move offshore today bringing strong and gusty southwesterly winds through until tomorrow.

The heaviest rain has already fallen, with a further 20-40mm of rain expected over the interior and east today, before rain tends to isolated showers on Friday.

- Weatherzone

Also comment by Blair Trewin from the BoM on the austpacwx list:

The range of places which have recorded 300+ daily falls so far this month is impressively diverse, covering such regions as the East Kimberley (Durack Range), the Gulf of Carpentaria (Mornington Island), outback Queensland (Bedourie), the NSW South Coast (Mount Darragh and Brogo Dam) and northeast Tasmania (Gray) - plus possibly the unofficial value at Tidal River VIC (although it's not yet clear to me whether this was for a standard rainfall day).