La Niña watch continues amid major Pacific temperature divide
Forecasters see signs that La Niña may arrive this fall and last into the winter months
Water temperatures in a key section of the Pacific Ocean continue cooling off as autumn approaches, a sign that we may enter a La Niña event in the next few weeks.
The gradual shift across the region could influence global weather patterns through the end of the year.
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Neutral conditions slowly flipping to La Niña
The El Niño-Southern Oscillation (ENSO) leads to periods of cooler- and warmer-than-normal waters around the equator in the eastern Pacific Ocean.
La Niña occurs when water temperatures in this area of the Pacific run at least 0.5°C cooler than normal for several consecutive months. El Niño is the warm-water opposite of La Niña.
We’re currently in ENSO-Neutral conditions, with neither La Niña nor El Niño present.
Forecasters with the U.S. Climate Prediction Center (CPC) continued a La Niña watch heading into this autumn and winter.
The agency predicts a 71 per cent chance that La Niña will arrive between October and December, with better-than-even odds that it may continue into the winter months through February.
La Niña can influence autumn, winter weather
La Niña can have significant impacts on global weather patterns, especially during the cool season.
During a classic La Niña event, we might expect to see below-seasonal temperatures across Western Canada while an active storm track builds over the Great Lakes and Eastern Canada.
All signs point toward a very weak La Niña event in the weeks and months ahead, which could blunt those typical effects.
One noteworthy change across the entire Pacific Ocean is the presence of very warm waters across the northern half of the basin between Asia and North America.
Sea surface temperatures across this region continue to run several degrees above seasonal. The contrast between warmer waters in the northern Pacific and chilly waters around the equator could hold more sway on weather patterns than the budding La Niña alone.
Header image created using graphics and imagery from Canva.