September 2008

RAINFALL

“Another disappointing rainfall result for Geelong,” was how Geelong Weather Services’ Lindsay Smail described September’s poor result.”Geelong received only around 30 mm which is 60% of the average”, he commented, adding that Otway catchments also suffered with a similarproportion of rain falling there. Across the urban area totals varied from 13.5 mm at Lara to 34.2 mm at Mt Duneed.West Barwon Dam received 66.8 mm – the average is 118 mm.The catchments now hold only 31% of capacity – a desperate result considering summer is on our doorstepand none of the long-term models are predicting above average rain for at least three months.”The major reasons for this continued dry spell are that the westerlies that bring cold fronts, troughs and rain have been tracking alonga more southerly trajectory for quite a time now, and are forced to the southeast by blocking highs in the Tasman Sea”, Mr Smail said. “As a result rainfall in southern and western Victoria has been suppressed and this trend is not expected to change until next year.”So far this year Geelong has had less than 250 mm, and only in July has there been above average rain. By now we should have had nearly 400 mm. “This looks like being one of our driest years -if we end up with around 350-400 mm for the year it could be classified as a drought year,” he said. Geelong’s lowest annual rainfalls have been in1967, 1982 and 2006. Our average rainfall over the past 30 years is only 516 mm, compared to 530 mm just 5 years ago.””I expect this cycle to gradually change over the next few years”, he added. “I am not a global warming alarmist.”

TEMPERATURE

Geelong was fractionally warmer than average this September. Average daily minimum was 6.4 degrees (average is 6.6) and average dailymaximum was 17.6 degrees (average 16.5). As a result we were 0.45 degree above the mean monthly temperature for September.On the warmest day, the 26th, the top temperature was 27.4 degrees and the lowest overnight temperature was 1.8 degrees on the 4th.This was our only frost for the month. No records were broken.

OTHER FEATURES

The other noteworthy feature of the month was the wind. Strong gusts over 60 kph were experienced on ten days; this is not unusual in spring,and the gusts of 94 kph and 100 kph received at Mt Duneed on the 14th and 15th respectively, despite reaching severe storm levels,resulted only in some damage to trees, signage and minor damage to some buildings.

RAINFALL DATA

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