La Nina to bring colder, drier winter

Sea surface temperature (SST) anomalies over the southern Pacific for the week centred on Sept, 30, 2020. (

MarketsFarm — There’s a La Nina poised to exert influence on the coming North American winter, according to Drew Lerner, senior agricultural meteorologist for World Weather Inc. in Kansas.

A La Nina generates colder-than-normal temperatures, as opposed to the warm temperatures garnered from an El Nino. Both weather phenomenon can be found over the Pacific Ocean.

For the Canadian Prairies, a La Nina will likely mean a drier bias on the whole, Lerner said.

“Usually in the early winter the cold is further to the west. In the late winter, it comes further to the east,” he said, noting this La Nina is expected to diminish come spring.

“If that’s the case, you would be more vulnerable to other weather patterns,” he said.

“If it’s a traditional La Nina, it will produce colder-biased temperatures in the western Prairies, with above-average snowfall along the front range of the mountains in Alberta and across parts of southern Saskatchewan.

For Manitoba, Lerner said a La Nina tends to have little impact.

“When we get into late winter/early spring, there’s some potent shots of cold that can come from that,” he said.

As for the U.S. Midwest, Lerner forecast below-normal precipitation for the western Corn Belt along with colder temperatures, particularly toward the end of winter.

“It’s important to know that the prevailing weather patterns for the winter, without La Nina, is for a tendency for troughs of low pressure over the eastern part of North America. There will be an open door for a cold shot to move across the central and eastern Prairies, down into the Midwest and northern Plains.”

However, Lerner exempted Ohio, Indiana and Michigan from the scenario, predicting these states should receive normal precipitation during the winter.

“The further west, the drier,” he said.

— Glen Hallick reports for MarketsFarm from Winnipeg.



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