Weaker Polar Vortex Just One Ingredient to an Interesting Pattern for Winter Storms Into February The Weather Channel 1/6/2021 Jonathan Erdman Replay Video UP NEXT Three interesting features in the weather pattern, including a weaker polar vortex, could combine to make the rest of January and February more active for winter storms and cold in the eastern United States. Interestingly, one of those features is not La Niña, the periodic cooling of water near the equator in the eastern Pacific Ocean, which intensified in the fall and can have impacts on winter weather in the U.S., including snowier winters for some.