The December-January-February (DJF) 2020-2021 temperature outlook favors above-normal seasonal mean temperatures for a majority of the CONUS and for northwestern areas of the Alaska mainland based on the impacts of La Niña, according to the NOAA discussion. The greatest probabilities (larger than 60 percent) are forecast for parts of the Southwest and the Rio Grande Valley. Below-normal temperatures are most likely for southeastern Alaska, parts of the Pacific Northwest, the far Northern Rockies, and the Northern Plains, consistent with impacts from La Niña conditions, especially later in the winter season.
The DJF 2020-2021 precipitation outlook depicts enhanced probabilities for above-normal seasonal total precipitation amounts for northwestern areas of Alaska, as well as across the northern tier of the contiguous U.S., including parts of the Pacific Northwest, the Northern Rockies, the northern Great Plains, the Ohio Valley, and the Great Lakes Region. Below-normal precipitation is most likely for Central and Southern California, stretching eastward to include the Southwest, the southern and central Great Plains, the Lower Mississippi Valley, and the Southeast.