National Weather Service: Snow Possible Later This Week

By Mary Ann Barton

The National Weather Service is giving Northern Virginia a chance of seeing some snow later this week.

"It looks like a coastal low is going to form off of the southeast coast," NWS meteorologist Heather Sheffield, who works at the National Weather Service forecast office in Sterling, said Monday afternoon. "We are confident a low pressure is going to form south of us and move north. If rain falls Thursday, there's the possibility of it changing into snow Thursday night into Friday."

"A rain-snow line usually forms with these systems, so DC might not get a lot," she said. "There sure is a possibility of snow Thursday night into Friday."

Even if there's no snow, get ready for some extra-chilly weather come Friday, she said. "So that low is going to move off the coast and turn Northeast, and a northerly flow is going to wrap around it and drag down Canadian air; that large surge of cold air is going to come down, so we may not even see 30 degrees on Friday and Saturday," she said.

"Temperatures will be in the low 40s on Thursday, so we may start off as rain and as the low moves further east, that will give us more cold air and change the precip into snow," she said. "It's probably going to be warm on the onset of the precipitation." 

The National Weather Service forecast is trending toward a coastal low pressure system forming and "that usually means we'll have precipitation," she said.

Here's the breakdown:

The weather service predicts Northern Virginia has a 30 percent chance of rain or snow starting Thursday morning, before 2 p.m. 

Any precipitation shouldn't freeze Thursday during the day, when forecasters expect a high of about 43 degrees (although it could mess up the Friday morning commute, when temps could hover near freezing). 

The chances for snow showers increase — going up to 40 percent — for Thursday night.

On Friday, there is a 40 percent chance of snow showers, and highs during the day will only reach 29 degrees, according to weather service. Friday night should be mostly clear with lows around 20 degrees.

The average high for January in the DC area is 43 degrees, according to the Weather Channel.