Bureau of Meteorology Summer Season Outlook Oct-Dec 2020
At the start of each summer extremes in temperatures and weather patterns present challenges to our fire and emergency response services. So, it is with great anticipation the emergency services wait on advice from the Bureau of Meteorology’s (BOM) on the summer outlook.
The October-December outlook for the start of summer holds some surprises for those anticipating the usual blast of warm weather as a La Niña weather pattern is predicted. For the uninitiated La Niña originates from Spanish, meaning “the girl”, and in weather terms it is a phenomenon that equates to cooler and wetter conditions.
From the BOM – ‘September is likely to be warmer than average across most of Australia, with roughly equal chances of warmer or cooler days and nights on parts of the south coast. Rainfall in the second half of September is likely to be average to above average across the country. The remainder of the year is likely to see above average rainfall across much of the eastern two thirds of the country. The Bureau’s ENSO Outlook is at La Niña ALERT, meaning there is at least a 70% chance of La Niña forming in 2020. The Indian Ocean Dipole (IOD) index has been at negative IOD values for three of the last four weeks; some models suggest a weak/borderline event may develop in spring. La Niña and a negative IOD typically increase the likelihood of above average spring rainfall across much of Australia.’
Based on current predictions we can expect a wetter than normal start to the summer season. If you review the attached rainfall mapping (Fig 1) it is evident that the large parts of Victoria have a 75% chance of exceeding median rainfall estimates.
Advice from VICSES is that planning is underway to deal with issues associated with the predicted weather pattern.
In closing it may be advisable to brush the dust off the recently stored brolly and prepare for some wetter than expected weather!
Information for this update was sourced from the BOM’s 2020-2021 summer outlook (http://www.bom.gov.au/climate/ahead/outlooks/ [accessed 16/09/2020] and advice from Banyule’s own Northcote SES.
