Thursday 20 March 2008

MEDIA RELEASE

Persistent high pressure system triggers southern heat wave

Much of southern Australia has just experienced an exceptional and prolonged heat wave, the result of a persistent high-pressure system in the southern Tasman Sea, according to a Special Climate Statement issued by the Bureau’s National Climate Centre.

Many centres, particularly in South Australia, set records for the most consecutive days with high temperatures.

Adelaide had 15 consecutive days above 35 °C and 13 consecutive days above 37.8 °C (100°F), breaking the previous records of 8 and 7 days respectively. These represent new records for any Australian capital city. Also breaking consecutive day records were Ceduna which had 12 days over 35°C, Mildura which had 14 days over 35 °C, and Kyancutta which had 13 days over 40°C.

In addition to the prolonged heat wave conditions, a number of record high temperatures for March were set, both for daily maximum and overnight minimums.

In Tasmania, Hobart reached 37.3 °C on 14 March which matched the record March high temperature from 13 March in 1940. At nearby Campania, the temperature reached 38.0 °C – the highest March temperature ever recorded in Tasmania.

In Western Australia, Eyre set a new all-time Australian record for the range of temperatures observed in one day. The overnight minimum of 6.8°C warmed to a maximum of a 44.2°C on 5 March, setting a new record single-day temperature range of 37.4 C.

Not only were the days hot, but warm nights also made sleep uncomfortable for many. Records for the hottest March nights were set in both Adelaide (30.2°C overnight on 13/14 March) and Melbourne (26.9°C overnight on 17/18 March.)

Mean maximum temperatures for the period 1 – 17 March are running far above average, with some locations in South Australia 12°C or more above their normal March value.

The “blocking high” in the Tasman Sea directed north to north-easterly winds through much of the southern part of the continent. While “blocking highs” are not unusual, the persistence of this system over more than two weeks is very rare in Summer and Autumn.

The whole Special Climate Statements is available from: www.bom.gov.au/climate/current/special-statements.shtml

Further information:
Dr. Blair Trewin (Senior Climatologist) office: 03 9669 4623
Mr. Neil Plummer (Head of the National Climate Centre) office: 03 9669 4714 mob: 0419 117865
Dr. Andrew Watkins (Head of Climate Analysis, NCC) office: 03 9669 4360 mob: 0439 381010
Mr. Darren Ray (Head of Climate and Consultancy section, South Australia) office: 08 8366 2664

Ends