The Climate Prediction Center and the International Research Institute for Climate and Society recently released a forecast favoring La Niña to set up within the next several months. La Niña is a climate pattern where trade winds that blow from east to west become stronger than normal, pushing warmer water towards Asia but upwelling colder water on the coast of the western United States. The colder waters in the Pacific push the polar jet stream further south in the north eastern U.S., leading to colder and wetter winters in the Great Lakes region with above average snowfall.
La Niña is the opposite of El Niño. El Niño occurs when trade winds weaken and warmer water is pushed back east, toward the west coast of the United States. This pushes the polar jet stream northward in the north eastern United States. This leads to warmer and more mild winters in the Great Lakes region with possibly drier conditions, a key factor that leads to less snowfall.
What does this all mean for our winter? Well, the forecast data is hinting toward a borderline or weak La Niña during the fall and winter 2021-22. It doesn’t look like we’ll see much of an impact here in the north east since La Niña is expected to be weak. The Climate Prediction center forecasts that we might actually see a slightly warmer winter with a chance of above normal precipitation.