Sunday, February 6, 2011

Severe Torrential rain in Melbourne, Heatwave in Sydney

Over Friday night and Saturday morning Melbourne and Victoria suffered severe torrential rain and flash flooding setting some new rainfall records. The rain was generated from ex-cyclone Anthony and ex-cyclone Yasi. 200 millimetres in of rain was dumped in some Melbourne suburbs in just two hours. Some of the roads in the Melbourne CBD were rivers of water when the deluge began just after 7pm on Friday.

The rain was a result of extreme storm activity generated by and drawing down moisture from Tropical Cyclone Yasi now in Central Australia after devestating the coastal towns of Tully and Innisfails leaving 180,000 houses without power and a trail of destruction across Queensland. Melbourne and many Victorian towns suffered flash flooding and were also put on flood alert.

Mildura experienced 147mm of rain on Saturday according to BOM d
, and Lyndhurst in Melbourne recorded 180mm of rain - a new record.

Stephen King, senior forecaster for the Bureau of Meteorology told the Sydney Morning Herald: "We have had extremely high moisture levels in the air from both ex-cyclone Anthony and Yasi ... Then we had a [cold] trough yesterday that triggered the thunderstorm activity," Mr King said.

"This sort of rain coming from the tropics, you get it in Sydney and Brisbane, it's not that unusual, but to get it this far south is probably quite rare."

800 kilometres to the north the mercury rose to new records in Sydney and surrounds setting new high temperature records.

According to the Bureau of Meteorology media release "This week minimum temperature records have been set at a number of locations across Sydney. February records were broken at Richmond (24.9°C, 72 years of record) and Bankstown (26.0°C, 43 years of record)."

"Records have also been set for successive hot nights. For example, Observatory Hill has had an unprecedented three nights, and Richmond two nights, above 24°C."

"The prolonged heat has been due to a hot northerly airstream coupled with high humidity, cloudy nights and high ocean temperatures."

The weather events in Melbourne and Sydney may be in the range of natural variability, but are highly unusual. So far we have warmed the atmosphere by a global average of about 1 degree. Professor Ross Garnaut warned on Thursday night "The science says that without mitigation - and with the sorts of emissions growth that my analysis shows will follow the industrialisation of China, of India, of Indonesia and the acceleration of economic growth in Africa - then that first degree is just the beginning," Professor Garnaut said in this Age report. "So if we are seeing an intensification of extreme weather events now, you ain't seen nothing yet." he said.

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