Autumn sun makes way for wet winter
CONDITIONS not seen off northwest Australia for almost four years are set to make Geelong experience wetter than normal winter weather — and a colder-than-usual week to start.
The Bureau of Meteorology’s seasonal outlook shows a slightly better than even chance of above median rainfall for winter, which for Geelong is 133mm.
Weather models show no clear trend for average maximum temperatures, but a more than 60 per cent chance of warmer than average overnight minimums.
Bureau of Meteorology head of long-range forecasts Dr Andrew Watkins said warmer than average temperatures in the eastern Indian Ocean would promote moisture to stream across the continent over the next few months — although it won’t have as big an impact on southwest coastal Victoria as it will on Central Australia.
The pattern allows the development of northwest cloud bands, so named for their origin and orientation across the county, which contributed to the moisture that paved the way for Geelong’s destructive
May 20 storm. “There is a chance they won’t happen, but it is favouring the formation of these northwest cloud bands,” Dr Watkins said.
“If they interact with cold fronts and low pressure systems, then we tend to get our best rainfall here in southeast Australia.
“Likewise with the increased cloud and moisture as well, that’s helping to moderate temperature a bit during the day, but at night trapping more heat in and keeping things warmer overnight.
“Certainly the moisture that has been coming in from the west has created some more unstable conditions over the past few weeks.
“We’re seeing the opposite from what we’ve seen generally in the last three of four years — probably 2016 or 2017 — since we’ve seen the Indian Ocean quite warm and hence generating more northwest cloud bands.”
The first week of June is expected to be generally much cooler and drier than normal for this time of year, with a severe weather warning in place for potentially damaging winds with showers today.
It follows a drier-than-average May, which finished with 28.6mm to put it about 25 per cent down on the 30-year average.
While May bucked the run of wetter than average months, daytime temperatures were cooler than normal for the fourth consecutive month, about 0.6C down on the average.
Autumn in Geelong had slightly cooler than average daytime temperatures by 0.7C, slightly warmer than average maximums by 0.3C.
It was the wettest autumn since 1989 statewide, but only since 2017 in Geelong, with the 145.2mm of rainfall recorded coming in about 25 per cent more rain than average.