Australia's east braces for warm winter after record May heat

Australia's eastern regions are wrapping up an exceptionally warm May, experiencing mean temperatures as much as 3 degrees Celsius higher than the long-term average. This unseasonable warmth is expected to persist, with the Bureau of Meteorology (BOM) forecasting one of the warmest winters on record for the southern parts of the country.

Daytime temperatures across southern states are predicted to be 1 to 2 degrees Celsius above recent decades, a warming equivalent to roughly 2 to 3 degrees Celsius compared to pre-industrial levels. This trend extends to much of Western Australia as well. The BOM's probabilistic forecast indicates that warmer-than-average conditions are almost certain, with a high probability, exceeding 80 percent, of unusually high maximum temperatures in the most populated areas.

This pattern follows a typical El Niño influence, characterized by less cloud cover which elevates maximum temperatures, alongside clearer, calmer nights. While El Niño usually brings frosty nights, warm sea surface temperatures developing off the southern coastline may counteract this effect, slightly favoring warmer minimums. Rainfall is expected to be below average across the nation's south.

The forecast for a warm and dry winter is concerning for the snow season. While individual snowfalls can provide temporary cover, historical data from El Niño years suggests an average reduction in peak snow depth of nearly 50 centimeters compared to neutral years. Preliminary data indicates that Sydney, Canberra, and Hobart have recorded their second-warmest Mays on record, with overnight minimums being particularly notable, sometimes exceeding the norm by as much as 5 degrees Celsius.