The Washington PostDemocracy Dies in Darkness

Snowfall Friday afternoon and night in D.C. area will probably be minor

But the snow could cause slippery travel and delays for the evening commute

Simulated radar from American (GFS) model Friday afternoon to Saturday afternoon. Universal time display; subtract five hours for Eastern time. (WeatherBell)
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Since Tuesday, model forecasts have shifted the track of the weekend coastal storm farther east, reducing the likelihood of significant snowfall in the Washington region. That said, we still think some snow will fall Friday afternoon and night, but it’s unclear how much it will amount to.

As we noted in Tuesday’s article, a period of light snow will probably develop Friday afternoon, but temperatures should be above freezing limiting accumulation initially. The chance for the snow to start sticking areawide will increase toward dark as temperatures fall, and roads could become slick for the evening commute.

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But it’s uncertain how long the snow will last into the night. Models have generally scaled back Friday night’s snow potential because they track the storm far enough east for drier air to move into the region from the west. Areas east of the District toward the Chesapeake Bay and over the Delmarva Peninsula have greater odds for accumulating snow Friday night that lasts into Saturday morning compared to places farther west.

At the moment, a coating to a couple inches of snow seem most likely in the immediate D.C. area, possibly increasing to up to a few inches near the bay.

Here’s is the probability of different amounts of snow for the District:

  • Chance of at least 1 inch: 40-50 percent
  • Chance of at least 3 inches: 10-20 percent
  • Chance of at least 6 inches: 5 percent

“Historically, this storm track doesn’t produce much snow in Washington,” said Wes Junker, Capital Weather Gang’s winter weather expert. “However, the disturbance triggering the coastal storm is strong enough that we can’t rule out some slick roads developing Friday evening or night if it actually snows because it’s going to be cold.”

What do the models say?

Most models show snow developing some time during the afternoon Friday, when temperatures are in the mid-30s or so. This means snow will melt or accumulate mainly on just grassy areas at first.

It may take until between 4 and 7 p.m. for temperatures to reach freezing and for snow to start sticking. The potential for slick spots on roads would reach our colder west and north areas first before advancing south and east.

While the snow may accumulate first in these colder areas, they’ll be the first to see the snow end as the coastal storm takes over late Friday night into early Saturday. That’s when most snow may accumulate in our eastern areas with temperatures falling into the 20s. Some snow could linger in our eastern areas near the bay into Saturday morning.

The most trustworthy models tend to project an inch or so around Washington and perhaps up to 2 or 3 inches toward the bay and Delmarva.

Here’s how a rundown of model snowfall forecast for the District:

  • American (GFS): 2 to 3 inches
  • European: 1 to 2 inches
  • Canadian: 1 to 2 inches
  • ICON: 1-inch
  • UKMet: 0.2 inches
  • NAM model: 0 inches

Based on model trends and the slight shift in the storm track toward the east, we’d lean toward lower numbers for the time being. We’ll attempt to refine our forecast on Thursday and provide a timeline and accumulation forecast map.