La Niña is a cooling of sea surface temperatures in the central and eastern Pacific Ocean near the equator. It can have an influence on weather patterns around the world. It’s the opposite of El Niño.
When a La Niña is present we sometimes see increased hurricane activity in the Atlantic Basin, and that is definitely true this year.
During a La Niña winter the polar jet stream, which drives weather patterns in the Northern Hemisphere, favors a northern track. In the western United States, that means the northern Rocky Mountains tend to be colder and wetter than normal. The south tends to often end up warm and dry. Keep in mind, however, no two La Niña episodes are ever exactly the same so there’s a ton of possibilities.
If you like to follow “The Old Farmers Almanac” they recently released their forecast for winter 2020-21. Their forecast is sure to please many people as they are forecasting a light winter, with warmer-than-normal temperatures for most of the United States. However, a few areas of the United States, including Northeast, Wisconsin, Upper Michigan, the High Plains, and northern Alaska, will in fact experience some heavier-than-usual snow. The Old Farmer’s Almanac added that a large portion of Canada would have a cold and frigid winter.