October 10, 2010

Batten down the hatches

Damaging 90km/h wind gusts and flash flooding is possible for people in the Southeast Coast district after the Bureau updated it's Severe Weather Warning at 11:05 am on Sunday 10 October 2010:

The combination of an intensifying high over the Tasman Sea and a deep trough off the southern Queensland coast is expected to produce wind gusts in excess of 90 km/hr, mainly along the exposed coast and over the islands.

As the trough moves closer to the coast expect increasing rain during the day with locally heavy falls developing from the south, particularly late in the day or overnight, with the possibility of flash flooding.

The State Emergency Service advises that people in the affected area should:
· seek shelter, preferably indoors and never under trees
· secure loose outdoor items
· beware of fallen trees and powerlines
· avoid driving, walking or riding through flood waters
(Source: BOM)

Additionally, Emergency Management Queensland issued a Severe Weather Advice today:

Emergency Management Queensland is urging all residents along the southern Queensland coast to prepare for heavy rain and strong wind gusts later today and tonight.

The Bureau of Meteorology has advised that strong wind gusts will occur in coastal areas with increasing rain throughout the day and heavy falls developing in the afternoon or tonight, with the possibility of flash flooding.

State Emergency Service (SES) volunteers are on standby but residents are being reminded to prepare their homes to best avoid damage to property.

People are being urged to listen to local radio, secure loose items, clear their gutters and to seek shelter indoors and not under trees.

A flood warning remains current for Sunshine Coast streams and Hinterland areas and people in those areas are reminded to avoid walking, driving or riding through flood waters.

Overnight the SES reported a quiet night with the latest information indicating that in the 24 hours to 5am today, volunteers in the Brisbane region attended 23 jobs, in the North Coast Region they completed 10 jobs and in the South East Region there were seven jobs.

Almost all of these jobs occurred yesterday and were of a minor nature.

For storm and flood assistance contact the State Emergency Service on 132 500 and in a life-threatening emergency call triple zero (000).

October 8, 2010

Spring has sprung...a leak!

Between 40-80mm of rain has fallen since 9am around the Gold Coast, with the heaviest falls around Robina (56mm to 11pm at Boobegan Creek) and Springbrook (83mm to 11pm).

The archived 256km Radar Loop for Brisbane
(provided by theweatherchaser.com) shows a line of rain/storms whilst relatively isolated to the coastal strip made it's way north from about Southport at midnight with heavy falls continuing until it disapated north of Maroochydore around 6am.

The morning on the coast was relatively dry until more moderate to heavy falls moving north-west made landfall around 10-11am in the centre of the coast, with a further band of showers heading south-east.

As the radar loop shows, as these two fronts combined, further rain started developing to the north of the Gold Coast in an almost 'circular' pattern (similar to a swirling low or cyclone). Currently the heaviest falls are to the north of Brisbane, with a Flood Warning issued by the Bureau at 11:06pm for Sunshine Coast streams and rivers.

As far as my personal opinion goes along with years of experiencing weather patterns in south-east Queensland, getting this much rain in Spring is really out of the ordinary. Normally from about September onwards, the only real 'rainfall' that we experience is from thunderstorms or lighter coastal showers.

However, it appears that this year, the weather pattern has changed with seemingly continuous showers and rainfall that doesn't seem familar to me. Maybe it's just that I've live most of my life in a drought situation in Queensland and never saw (or had the tools to see) how weather patterns existing pre 1990.

From what I can see, the rainfall we are experiencing at the moment almost represents an East Coast Low situation that whilst they can occur at any time of the year, they are more prominent in autumn and winter. Additionally, the radar images show a 'circular' pattern which also appears to be related to a low pressure system, but normally the heavier rain falls occur on the southern side of the low. Tonight's weather pattern shows the heavier falls to the north.

In my mind, I can only assume that these weather patterns is because of La Niña climate phase. According to a BOM media release in June:

Historically, La Niña events have often, but not always, brought above average rainfall to much of Australia, particularly inland eastern and northern regions. Night time temperatures are also usually warmer than average. Tropical Cyclone risk for northern Australia also increases during La Niña events.

Widespread wet conditions and flooding events have accompanied a number of La Niña events in the past. Substantial flooding impacted NSW and Queensland in the event of 1998, while the event of 1988-89 saw flooding also occur in SA and Victoria.

In general, while La Niña events tend to be wetter than normal for Australia, no two La Niñas have exactly the same impact on local rainfall. So while some regions may experience the typical pattern of heavy rainfall, other regions may miss out altogether.

Actually, I do remember the flooding in 1998 - from memory there were actually two flooding events no more than about 1-2 weeks apart (this is when I was living on the Sunshine Coast). The second event started around 8:30 at night - as we were trying to watch 'Ally McBeal' on TV and because we had a tin roof, the rainfall got so heavy the TV wouldn't go any louder.

Throughout the night it just kept raining and raining, our backyard was under water, the street was under and the water came halfway up our driveway. We were lucky as our house was slightly higher than the other end of the street. Some of our distant neighbours had water lapping at their doors, with one house having raw sewerage coming out of the drains in the floors of the bathrooms because it had no where else to go.

Anyway, I'm interested to know for those of you who've lived here longer than I have, describe what your opinion of the weather patterns have been over the past month?