Non-sticking sleet and snow falls in D.C. area

3:00 p.m. update: The final batch of mixed wintry precipitation has arrived and should continue for the next two to three hours. Per the 2:25 p.m. update, we’ll probably see a trend for more of the mix to become snow, but all indications are that most of it will melt on contact with the ground. Even towards the mountains in west central Virginia the snow is only accumulating on grassy areas (note bare sidewalk in picture from Harrisonburg below):

This is the last update in this post. Ian Livingston will have a fresh look at the forecast in his PM Update which will be up by 3:30 p.m.

2:25 p.m. update: One batch of mixed rain/sleet/snow is now exiting the region, but there’s one more batch to the southwest still to come through. It’s likely to be of similar character to the first batch (with alternating precipitation types), but – with temperatures cooling some into late afternoon – might tend more snowy. I still think a coating on grassy areas is about the most anyone will see and do not anticipate icy roads. The way it looks now, this should wrap up from southwest to east between 4 and 6 p.m.

Radar snapshot at 2:20 p.m. showing final burst of precipitation in central Virginia headed towards the D.C. region. (National Weather Service)

Radar snapshot at 2:20 p.m. showing final burst of precipitation in central Virginia headed towards the D.C. region. (National Weather Service)

1:50 p.m. update: A sign this snow “event” is, shall we say, struggling (not that we expected much more): I have yet to receive a compelling image of snow-filled skies. Despite several pleas, this is the best picture I’ve received so far on Twitter, and it’s not even that close to the District, from Eldersburg, Maryland:

All I’ve received so far is a promise:

1:20 p.m. update: We’re seeing a pattern where areas see sleet and snow when precipitation increases in intensity, but plain rain when it wanes. This is happening because temperatures at the ground are relatively warm (37-40). Even though it has become cold enough for frozen precipitation at high altitudes, it’s melting by the time it reaches the surface – unless it’s coming down hard. As such, most snow should remain “conversational” (not sticking). Roads are not a concern and it will only whiten grassy areas if/where it picks up in intensity (best chance near and east of I-95 the way it looks now).

1:00 p.m. update: The high-resolution NAM model has what appears to be a reasonable simulation of the snow.

High-resolution NAM model snow simulation.  This simulation is a coarse representation meaning details are likely off. (WeatherBell.com)

High-resolution NAM model snow simulation. This simulation is a coarse representation meaning details are likely off. (WeatherBell.com)

It shows any accumulation (again – mostly on grassy areas) is quite light and patchy (coinciding where heavier bands develop) in the region. Its amounts, if anything, are probably overdone – especially west of I-95 (radar shows heaviest precip along and to the east). It has snow exiting the region by 3 to 4:00 p.m. So this should be a quick hitter and we may not have to worry about it continuing through dark when temperatures drop.

12:50 p.m. update: The National Weather Service has issued a Special Weather Statement about the snow. Excerpt (I’ve put key point in bold):

Cold air will cause any remaining precipitation to changeover from rain to a mixture of light sleet and snow early this afternoon … Then to all light snow by mid afternoon. Precipitation will end by early this evening.

Areas along and east of interstate 95 will likely see snow accumulations from a dusting to up to an inch of snow by sunset … Mainly on grassy surfaces. Pavement temperatures are in the upper 30s to lower 40s … So accumulations on pavement are not anticipated. The area most likely to see up to an inch of snow will be Southern Maryland.

12:20 p.m. update: It’s about to get interesting locally, as some moderate precipitation coming up from the south merges with the cold air streaming in. We might see some moderate sleet and snow between 12:30 and 2:30 p.m. or so. It’s possible grassy areas become covered as temperatures now in the upper 30s to near 40 fall back into the mid-30s. Roads should remain wet, not icy.

Radar grab at 12:15 p.m. (RadarScope)

Radar grab at 12:15 p.m. (RadarScope)

12:10 p.m.: We’re now officially into phase III of this storm: the wintry, closing phase. Phase II, the wet phase, dumped hefty quantities of rain – generally just over 2 inches, with amounts varying from 1.5-3 inches around the region. Useful link: Rainfall totals from National Weather Service

12:05 p.m. update: Here’s a sample of some of the initial sleet and snow reports that have come in via Twitter…

 

 

 


Radar & lightning: Latest regional radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

Overview, noon: Cold air is zipping into the region at high altitudes as a big storm cranks up in New England. Rain will transition to sleet and snow this afternoon (the changeover process began around 11:45 a.m.). As temperatures will mostly remain above freezing, any accumulation of snow/sleet is expected to be light and mainly on grassy surfaces.

Colder locations west and northwest of Washington (western Fairfax, western Montgomery, Loudoun, Frederick counties) could see a few slick spots if heavier snow develops, especially it persists into the evening when temperatures will drop.

Snow should end late this afternoon or early this evening from southwest to northeast.

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