After a brief thaw earlier this week winter has made a return to our area. The cold front and the associated heavy rain that passed through overnight Tuesday brought in a colder air mass and has helped set the stage for some light snow for late Thursday night into early morning Friday. While this will not be a blockbuster snow storm, the timing of the snow could make Friday morning travel difficult.
An area of low pressure called the primary low will trek across the Midwest into the Tennessee Valley during Wednesday night and Thursday. As the low pressure system moves towards the East Coast, a separate area of low pressure called the secondary low will form off the North Carolina coast and strength as the primary low in the Tennessee Valley transfers its energy to the secondary low. The strengthening secondary low will move northeast off of the Virginia coast. This type of coastal low pressure system is common during the winter and is called a Miller B type snowstorm. The bulk of precipitation that will affect the DC metro area will be associated with the primary low as the secondary low will move to far east to bring appreciable snow to our area.
Current model consensus has light snow moving into the area after 10 PM Thursday. Most of the snow over night will be light snow with the possibility of moderate snow bands during the early morning hours of Friday. The moderate snow will begin to leave the area after 8 AM with the possibility of light snow and flurries throughout the morning hours.
Snow fall Predictions
The National Weather Service Sterling currently has 2-3 inches of snow for the immediate DC metro area, with slightly more farther south and east. This prediction seems reasonable given the generally good consensus between the different weather models.
The temperatures during the event will be near or even slightly above freezing, which could cut down the amount of the snow that accumulates especially on roads and side walks. Another uncertainty is where the dry slot sets up. The North American Model (NAM) on Wednesday had multiple model runs which showed little accumulation for our area. The area where the dry slot sets up will have less accumulation, however, forecasting the dry slot is notoriously difficult and could set up over our area.
Regardless of final snowfall totals, travel during late night Thursday into early morning Friday could be difficult and as always continue to check the UMD weather Facebook and Twitter pages for the latest on this late season snowstorm.