The Washington region will see the weather flip from 60 degrees to snow in less than 24 hours this weekend. But this latest blast of wintry weather, while jarring, shouldn’t be too problematic for those attempting to get around on Super Bowl Sunday.
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Although some areas, especially south of the District, could see a quick inch or two of snow early in the day, other areas may not see much more than melting snowflakes.
Most of the snow should exit by midmorning Sunday. In places that do see a quick burst of snow early in the day, we can’t rule out some slick spots before conditions gradually improve. Most areas should be clear leading up to the evening.
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“Sunday’s snow looks like a minor event, at most, with snowfall limited to a coating to an inch or two wherever a consolidated stripe of snow develops early Sunday morning,” said Wes Junker, Capital Weather Gang’s winter weather expert. “The system never taps into Atlantic moisture, so snowfall should be light.”
Accumulation potential and model forecasts
Computer models are pretty consistent in showing the steadiest precipitation and potential for snowfall accumulation south of the District. However, those areas will have the mildest temperatures, meaning some of the snow that models are projecting won’t stick. Right around the District, the predicted amounts are generally modest, but there are a couple of models that show the potential for 3 or 4 inches (in reality, it’s less than that since some projected snowfall won’t accumulate).
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Here’s how much the various models project:
UKMet and ICON: 0 inches European: 0.5 inches American and SREF: Around 1 inch High-resolution NAM: 1 to 2 inches Canadian: 2 inches NAM: 3 inches High-resolution: Canadian: 4 inches
Our accumulation outlook (shown above) reflects a blend of these forecasts while accounting for the mild temperatures ahead of the system, which will cause some snow to melt. We understand the range of a trace to 2 inches is large, and we’ll attempt to narrow this range in our final accumulation outlook that we’ll release Saturday; that’s when we’ll get a better handle on where steadier snowfall may concentrate.
We see the chance of an inch in the District at about 40 percent.
The National Weather Service’s forecast, shown below, is more or less consistent with ours.
“The big question mark that remains is whether there will be a localized band of more intense snowfall early Sunday and, if one develops, where it will be located,” Junker said. “Without one, snowfall amounts will probably be limited to less than an inch as the temperatures will be above freezing at the precipitation onset. How quickly temperatures fall, in part, will depend on the intensity of the snow.”
Event timeline
A cold front will sweep across the area Saturday, abruptly ending our spree of springlike weather by Saturday night. Temperatures that peak near 60 early in the afternoon will steadily fall back starting late in the afternoon. Overnight, they’ll slide back through the 30s, probably settling near freezing near sunrise Sunday.
Rain or a rain-snow mix will spread over the region as temperatures fall late Saturday night into early Sunday, before gradually transitioning to snow. But the snow should end quickly Sunday morning, with just an outside chance of it extending into the afternoon, mainly in our southern areas.
In the timeline below, the lowest temperatures are expected in our northwest areas while the steadiest precipitation is most probable in our southern areas:
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10 p.m. Saturday to 2 a.m. Sunday: Chance of rain or rain-snow mix developing. Temperatures: falling from the 40s into the upper 30s to near 40.
2 a.m. to 6 a.m.: Rain and snow changes to snow. Temperatures: falling to 30 to 35 degrees.
6 a.m. to 10 a.m.: Snow tapers off northwest to southeast. Temperatures: 30 to 34 degrees.
10 a.m. to 2 p.m.: Partial clearing, except chance of lingering snow well south of the District. Temperatures: rising to mid-30s.
Event impact
This event rates as a Category 1 “nuisance event” on our 1-to-5 winter storm impact scale. Its effects on the region will be mitigated by several factors:
Temperatures ahead of the storm will be mild, meaning the ground won’t be frozen. This means snow will initially melt before accumulating. Most of the snow is predicted to fall before dawn on Sunday, when there is little traffic and most schools are closed (outside of religious/Sunday schools). The likelihood of heavy snow, falling at the rate of an inch an hour or more, is low.
On Saturday, we’ll post one more detailed briefing on this snow potential and attempt to refine predictions.