While some La Niña-like conditions have led to cooler temperatures across some parts of Australia this spring, there is uncertainty around whether such conditions could continue through the remainder of the year.
Forecasts say there is a chance Australia could experience La Niña conditions through the rest of the year, but other models suggest a “neutral” spring and summer—meaning temperatures and rainfall would likely fall into average ranges across Australia and not conform to La Niña (wetter) or El Niño (drier) events.
This comes on the back of Southern Queensland experiencing a cooler spell from Sept. 13 to 19, which came about as a result of strong south-to-south-easterly winds bringing a cold air mass from the south, coupled with clear skies at night.
Colder patches in September are not considered overly unusual for Australia, but forecasters are uncertain whether Australia’s summer will be wetter, and sometimes cooler, as part of a La Niña system.
A La Niña event occurs when stronger than usual winds push warm water towards the western Pacific, often leading to wetter conditions in the western Pacific, but drier conditions in the eastern regions.
In contrast, an El Niño event results from weaker winds, leading to warmer seas in the central and eastern Pacific.
Future weather trends can be gleaned from what is known as the Southern Oscillation, a periodic fluctuation in atmospheric pressure over the southern Pacific Ocean that can influence weather patterns.
Current predictions have resulted in a “watch” level of warning for a La Niña warm season.
The weather bureau’s outlook scale has seven categories, with La Niña and El Nino at opposite ends.
“While some atmospheric indicators such as pressure, cloud, and trade wind patterns over the Pacific have been more La Niña-like over the past few weeks, it remains to be seen whether these conditions will be sustained,” a Bureau of Meteorology spokesperson told The Epoch Times.
The Bureau’s model suggests sea surface temperatures (SSTs) are likely to continue to cool.
“Three of seven climate models suggest the possibility of SSTs in the tropical Pacific exceeding the La Niña threshold from October, and another three models forecast SSTs to come close to, or just exceed, the threshold.
“It is possible a La Niña may develop in coming months but if so, it is forecast to be relatively weak (in terms of the magnitude of the SST anomaly) and short-lived.”
The most recent long-range analysis indicates above-average rainfall is likely across much of Australia’s eastern two-thirds, while Western Tasmania is likely to see drier than average conditions.
Rainfall is predicted to be within the typical seasonal range across Western Australia, the eastern Northern Territory, western Queensland, and southern Victoria.
Australia’s typical annual rainfall ranges between 1,000 to 1,500 millimeters.
Warmer than average days and nights are likely across most of the country.
