July 2011

RAINFALL

A diverse rainfall pattern was the picture for July around Geelong. The Geelong urban area average for July is 49 mm. Many stations across the suburbs(eg, Bell Post Hill 47, Grovedale South 56, Drumcondra 50, to name just a few) were hovering around that long-term average. The new Breakwater Racecourse AWS however,has proven to be not representative of the whole urban area since it and the other two daily reporting BoM stations at Moolap, just 3 kilometres away, only reported 36 mm. BoM figures from these stations, purporting to be for Geelong, will need to be used carefully in that light. The GWS station at East Geelong also only recorded 37.5,and, quite pointedly, the GWS site closest to the Airport (1 km) recorded 67 mm in July.

In contrast, the northern areas from Lara to parts of the Brisbane Ranges, were well down in totals – the Lara district had between 19 and 26 mm – whereas the Otways including the water catchment areas received well above average. West Barwon Dam received 198 mm (around 140% of the normal July total), creating an 86% full system, the best month since January, 2002, nearly ten years ago.

TEMPERATURES

Once again I have to report that, in spite of my requests, the Bureau has not yet released data for June or July for the Airport AWS, due for demolition withina few weeks. These data are crucial for being able to compare the new Racecourse site with the old one, and are being witheld for some reason. I believe this is unacceptable, yet despite several polite requests, my concerns have been ignored by the person responsible. The point is that the new site is very clearly an urban site, with expected higher temperatures, especially overnight. The old site was more rural andtherefore more likely to be cooler. To compare our monthly temperature trends we need to compare apples with apples. Having said that, it was interesting to note that in July the average daily maximum at the new Racecourse site was actually the same as the long-term average for the Airport. When the full figures are made available more conclusions may be drawn.

Highest daily temperature was 20.3ºC on the 31st, and the coldest day reached 10.5ºC on the 23rd. Coldest overnight was -0.6ºC on the 16th, and warmest overnight 10.6C on the 3rd. Average minimum for the month was 6.6ºC and average maximum was 14.0ºC. Long-term average Geelong Airport figures are 5.5ºC and 14.0ºC respectively.

OTHER FEATURES

It was a fairly settled month. There were no storms and no thunder days. There were only four days of very strong winds, with a maximum gust of 72 kph on the 5th.

There was one frost on the 16th.

RAINFALL DATA