May rainfall was generally well below average for most of the Geelong region, according to Lindsay Smail of Geelong Weather Services yesterday. Most places received less than half of their average May figure, and some fared much worse. Compared to last year, when Geelong received 100 mm in May, this year the falls ranged from 12.5 mm at Lara to 36.4 mm at Leopold South. The Geelong average for May is 47.2 mm.
On the other hand, Melbourne CBD received 53 mm compared with its normal 57. However, Otway water storage areas were also well down. At Forrest, site of the West Barwon Dam, only 62.4 mm was recorded, compared to the May average of 108.4. Runoff into the dam was very small.
When asked if a winter drought was forthcoming, Mr Smail explained that three-monthly predictions based on computer models and SOI phases, showed that the Geelong region and most of Western Victoria stood a good chance of receiving above average winter rainfall this year.
“Sea surface temperatures in the Pacific and Indian Oceans help to determine the amount of moisture in the atmosphere passing over southern Victoria,” he said. “With those trends now established, there is a good chance of better-than-average winter rains.”
“The El Nino-Southern Oscillation figures have risen from minus 22 in April to minus 3 in May. In the past a rise like this has usually meant good rainfall for this region in the next three-month period. But this does not necessarily mean it is a certainty this year. In fact, in the short term, things look fairly dry for the next week or two. This may mean that pasture growth is restricted.”
May was slightly cooler than average. Average minimum temperature was 7.8 degrees, compared to the average 8.1. Average maximum was 16.5 compared to 17.2.