It’s no shock that we’re in for a soggy spring this year considering La Niña keeps coming back like a dog with a bone. But now it’s joined by a friend, another weather pattern that indicates a higher chance of summer rains. Meet SAM — the new sopping thot on the radar.
According to the Bureau of Meteorology, SAM (or the Southern Annular Mode) is currently “strongly positive” which means a belt of westerly winds between Australia and Antarctica known as the “roaring 40s” and “furious 50s” are being pushed south and away from the country.
A positive SAM increases the likelihood of rains in eastern NSW, far-eastern Victoria and parts of southern Queensland. But it can also cause parts of southwest and southeast Australia to dry out — just to keep everyone on their toes, I guess.
The SAM weather pattern moves through three phases — positive, neutral and negative — which influence the amount of rainfall on the eastern side of Australia especially. Essentially positive SAM in summer = more rain, and negative SAM in summer = less rain.
These weather patterns tend to stick around for a couple of weeks at a time but apparently, this windy binch is set to hang around in its positive state for most of spring.
Meteorologist Andrew Schmidt told The Sydney Morning Herald that the recent run of freezing cold fronts was the effects of SAM in negative winter mode.
“When southern Australia had that conveyor belt of cold fronts in winter that never seemed to end, the SAM was in negative mode,” he said.
“At the moment, SAM is more positive, and we aren’t having as many cold fronts.”
Unlike La Niña or the negative Indian Ocean Dipole — which bring deluges of wet weather — the SAM systems aren’t dictated by ocean temperatures. SAM is all about the atmosphere, which means it shifts faster than its oceanic counterparts and hopefully will swing away from its rainy pattern much more quickly.
Until then, get ready to have a sloshy spring because it’s gonna be good weather for ducks.