Don’t put your umbrella away just yet – BOM’s weather outlook for Northern NSW

The bureau has delivered its climate prediction for August to October 2021, and it has also explained why it feels like this winter has been cooler than normal.

The senior climatologist said average precipitation for the Northern Rivers in August to October means 150mm of rain in Lismore, 156mm in Ballina and 167mm in Byron Bay.

The Bureau of Meteorology has predicted a wetter than average weather period for August to October 2021.

Senior climatologist Felicity Gamble said the latest report by the bureau means Northern Rivers resident should keep them umbrellas close by.

“The current outlook for the three-month period August to October shows quite high odds — or high likelihood — of getting above normal rainfall for that time of the year,” she said.

“That’s really the case for most of eastern Australia and much of South Australia and the Northern Territory.”

Ms Gamble said the wet forecast included the rest of winter and all of Spring 2021.

“We have a couple of things that are driving that wet signal across the eastern half of Australia,” she said.

“One of the main reasons for that, at the moment, is very warm surface temperatures to the north of Australia and in the eastern Indian Ocean, and those warm temperatures in the eastern Indian Ocean in particular are looking like the beginning of a negative Indian Ocean Diapole.

“A negative Indian Ocean Diapole is a little but like the La Nina pattern.

“La Nina brings wetter than average conditions, and it is driven by temperature changed in the Pacific Ocean.

“The Indian Ocean Diapole is like that, but for the Indian Ocean.”

The seasonal outlook is a probability model, so it’s not possible to know so far ahead if the rain will come as strong storms, ongoing rain or other patterns.

The senior climatologist said average precipitation for the Northern Rivers in August to October means 150mm of rain in Lismore, 156mm in Ballina and 167mm in Byron Bay.

In regards to temperatures, Ms Gamble said the extra rainfall will bring temperatures close or even below average.

“Slightly below average or average temperatures are possible in that period,” she said.

“In recent years, most seasons have been warmer than average, so we have always become accustomed to warmer than average seasons, so even having a normal season, like this year, feels quite cold to us.

“This winter has been average, to even sometimes above average temperatures, but everyone is saying ‘oh, it’s so cold!’ and that’s because we are used to warmer seasons.”