*Winter Storm Warning from 4am SUN to 4am MON**Freezing Rain Advisory from 4am SUN to 4am MON*
A storm developing in Midwest will head east today, overspreading mixed precipitation across the Washington, DC area by tomorrow morning. Today will be mostly sunny and brisk with highs in the low 40s. Tonight temperatures will drop below freezing setting the stage for some icy precipitation on Sunday. Our current expectation is that this will be a low to medium impact event for the immediate metro area with an eventual changeover to rain probable.
|Winter Weather Forecast: Sunday AM to Monday AM|
3am to 8am SUN: Light snow and sleet begins from west to east, light accumulations; Temps 26-29.
8am SUN to 1pm SUN: Light to moderate mixed precip. Snow and sleet N and W, freezing rain and sleet metro area; Temps 28-32.
1pm to 6pm SUN: Sleet/freezing rain, probably changing to rain and drizzle in metro area; Temps 31-35.
6pm SUN to 6am MON: Drizzle or freezing drizzle in metro area, freezing drizzle and flurries N and W; Temps 29-34.
|Storm Impact: Travelcast:Schoolcast (Mon.):|
Frequently Asked QuestionsWhen/where will the heaviest frozen precipitation fall?
Most likely in late morning to early afternoon on Sunday, with the highest risk of accumulations of frozen precipitation in the north and west suburbs (places like Manassas, Leesburg, Centreville, Gaithersburg, Frederick).Will the snow/ice accumulate?
In the colder north and west suburbs, the mixed precipitation will accumulate sooner and quicker. In the metro area, some accumulation is possible particularly on untreated surfaces during heavy periods of precipitation before noon Sunday.When will travel be most difficult?
From Sunday morning into the early afternoon.Could there be power outages due to ice?
Some scattered power outages are possible in the colder suburbs north and west of DC but this probably won't be as big a problem as the last storm due to slightly warmer temperatures and less wind.What about precipitation type?
This is the most complex aspect of this storm to forecast. The precipitation may briefly start as snow for much of the area. There is some potential for light accumulations of up to an inch particularly in the north and west suburbs. Sleet may be the predominant precipitation type in the metro area through early afternoon with some freezing rain possible as well. The exact distribution of sleet and freezing rain is difficult to predict. During the afternoon, it is likely the precipitation will change to rain or drizzle in the metro area. Unlike the last storm, a continuous feed of cold air from the northeast is not likely and temperatures will likely get above freezing, though it's possible this doesn't happen until the bulk of the precipitation has fallen.When will conditions improve?
Most likely mid to late afternoon on Sunday, as precipitation begins to taper and temperatures rise above freezing. However, in areas north and west, light freezing drizzle may linger overnight Sunday.Could it fizzle out?
Yes. Storms coming in from the west with marginal cold air often underperform in the DC area. Several things could happen that reduce the storm's impact. 1) A later storm arrival Sunday morning may allow temperatures to rise above freezing before the precipitation starts. While temperatures could briefly drop back below freezing during the precipitation, just marginally freezing temperatures coupled with late February insolation (sunlight through the clouds) could reduce the risk of snow/ice accumulation in the metro area. 2) As the primary low to the west weakens and the new coastal low forms, we could get "dry slotted" beginning late Sunday morning reducing precipitation amounts. 3) The cold air erodes more quickly than expected due to warm air aloft mixing down to the surface and/or surface winds shifting more quickly to easterly -- resulting in mostly rain.Could the storm bring more snow or ice than expected? Yes.
It's possible, that like with the last storm, the cold air holds a bit longer than expected in the metro area resulting in a more significant icing event. However, the supply of cold air for this storm is not as impressive so it's very unlikely this storm will have a comparable impact.What are other forecasters saying?
The National Weather Service has issued a Freezing Rain Advisory for the area suggesting the likelihood of up to 0.2" of ice accumulation.What's the bottom line?
A low to medium impact winter weather event is likely, with some snow/ice accumulation possible, particularly in the colder suburbs north and west of the city (north and west of western Fairfax County and central Montgomery county).