La Nina system could persist into spring, new forecasts suggest

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Those hoping to pack away their umbrellas soon may have to wait a while longer as the La Niña pattern could persist into spring, two new US-led forecasts suggest.

The new modelling was released by Columbia University’s International Research Institute for Climate and Society (IRI) and the US Climate Prediction Centre (CPC) last week.

Current sea surface temperature anomalies in the Pacific Ocean, showing a distinctive La Niña pattern with cooler-than-average water in the central and eastern equatorial Pacific Ocean and warmer-than-average water in the western equatorial Pacific Ocean.
Current sea surface temperature anomalies in the Pacific Ocean, showing a distinctive La Niña pattern with cooler-than-average water in the central and eastern equatorial Pacific Ocean and warmer-than-average water in the western equatorial Pacific Ocean. (NOAA)

“According to the latest IRI/CPC model forecast, La Niña has a 62 percent chance of persisting through the southern hemisphere winter and a 58 percent chance of occurring in spring,” Weatherzone said.

Should the pattern persist as predicted, the likelihood of above-average rain in parts of Australia would increase across winter and spring.

The Sydney Harbour Bridge seen through the windscreen of a car as rain pours on the city, Monday, Feb. 28, 2022. The state of New South Wales has seen more than 500 flood rescues and 927 requests for assistance in the past 24 hours as record rain continues to fall across the eastern states of Australia. (AP Photo/Mark Baker)
Sydney has had more rainy days then dry ones this year. (AP Photo/Mark Baker) (AP)
The Windsor Bridge was inundated by floodwaters along the Hawkesbury River on March 09, 2022 in Sydney, Australia. (Getty)

It comes after Sydney was confirmed to have had more wet days than dry ones this year with 94 of 142 recording rain.

Two factors are driving the new forecasts.

Average winter-spring rainfall (top) from 13 La Niña years combined, indicating average rainfall and temperature footprints of La Niña.
Average winter-spring rainfall (top) from 13 La Niña years combined, indicating average rainfall and temperature footprints of La Niña. ( Bureau of Meteorology)

Sea surface temperatures are “near or exceeding La Niña thresholds in late winter, and secondly, a negative Indian Ocean Dipole (IOD)appears to be developing over the coming months.

Towns cut off by floodwaters for second time this year

“A negative IOD also increases the likelihood above-average rain and cooler-than-average daytime temperatures in Australia,” Weatherzone said.

“In fact, a number of forecast models suggest that we could see a strong negative IOD this winter and spring.”

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