D.C. should brace for a cold December with chances of snow.
The month could resemble December 2010, which was notably colder than average.
After a cool October and a marginally warm November, a cold December may well loom for the D.C. area. We project temperatures 2 to 4 degrees below the recent 30-year average and would not be shocked if it is even a little colder.
We also lean toward a drier-than-normal month, with overall precipitation (from rain and melted snow) about 1 to 2 inches below average. Even so, the cold air should offer opportunities for snow, and our best guess is around 1 to 3 inches, which is in the normal range.
Our confidence in the monthly snow forecast is very low, as just one substantial storm could easily surpass that amount. We think the chance of a significant snow event is somewhat elevated.
This prediction for a cold December is a reversal from our winter outlook issued on Nov. 15, as short-term influences on the weather pattern have evolved and trended more wintry.
The big elephant in the room is the development of a large high pressure zone over Greenland, unanimously predicted by computer models. As Capital Weather Gangs Ian Livingston wrote earlier this week, such a Greenland block increases the likelihood of cold and sometimes snowy weather in the Mid-Atlantic.
https://www.washingtonpost.com/weather/2022/12/01/december-weather-outlook-dc-cold/?