Snow and sleet blanketing DC area, heavy at times through the night – Washington Post

* Winter storm warning for areas along and west of Interstate 95 in D.C. area, including the District, 7 p.m. Monday to 2 p.m. Tuesday | Winter weather advisory in Stafford, Charles, Prince George’s and Anne Arundel counties |  School closures and delays  | Washington Post roof view *

Snow and mixed precipitation, heavy at times, will fall overnight. With temperatures falling near and below freezing in many areas, roads are likely to turn slick as the night wears on and into the Tuesday morning commute.

The heaviest snow accumulations are likely in Washington’s far north and west suburbs, and may exceed six inches. Travel may become very difficult in this region. Inside the Beltway, the snow should mix with and change to sleet and possibly freezing rain or plain rain, limiting accumulations to the two to four inch range. Farther to the south and east, any snow will be brief with a fast changeover to sleet and rain and accumulations less than two inches.

Follow our updates on the storm through this evening below…

11:55 p.m. update: The snow has mixed with or changed to sleet and some freezing rain in parts of the District. Between approximately midnight and 3 a.m., we should see that transition line continue to make progress to the north and west, with sleet and freezing rain perhaps pushing well into Montgomery and Fairfax counties. Everyone could go back to mostly snow after 6 a.m. or so, before precipitation starts to taper by around 9 a.m. Temperatures are currently below freezing across the entire area and roads will become increasingly hazardous overnight into the early morning.

We’re taking a break for a few hours, but will resume with live updates in this same post by around or before 5 a.m. Until then, the radar above will continue to update. And remember, our snow/sleet forecast map remains unchanged from earlier, and can be found at the bottom of this post.

11:25 p.m. update: The snow has been coming down heavy in parts of the area, especially around and inside the Beltway, coating the grass and some roads. Some spots have already reported over an inch. Time for some pics!…

10:35 p.m. update: Heavier snow, with perhaps some sleet, is moving into the DMV. Everyone should see the snow accumulate nicely before sleet tries to intrude into much of the area after midnight or 1 a.m., except for the far north and west suburbs which should stay mostly snow. With temperatures falling to at or below freezing, it should be a snowy/icy mess out there late tonight into the morning, which is why so many schools have already closed. Everyone could change back to snow for a bit before the precipitation starts to taper by 9 a.m. or so.

Speaking of that transition from snow to mixed precipitation, the National Weather Service Storm Prediction Center is advertising that changeover to sleet, possibly even some freezing rain, for the I-95 corridor from D.C. to Baltimore in its map below. The NWS accompanying text states “several recent model runs suggest that this southern fringe of the snow zone may begin to mix with/change to sleet or freezing rain around midnight.”

9:55 p.m. update: An area of steadier and heavier precipitation, likely to be mostly snow, will overspread much of the area over the next hour. Look for snow to accumulate nicely on grass first, but fairly quickly it could start to cover roads. Some sleet may mix in as well. Now is the time to stay put as conditions begin to deteriorate, with temperatures dipping to near or just below the freezing mark during the next couple hours.

9 p.m. update: We’ve had a variety of precipitation types reported across the area in the last hour. We expect the precipitation to become mostly snow as it becomes steadier and heavier over the next hour or two, but with more mixing overnight as discussed below. Already we hear that grass and cars are picking up a light accumulation of snow, but roads still in good shape. Note, though, that temperatures have cooled considerably, down to around 32-24 in most spots, so some roads in our colder suburbs could become slick in the next couple of hours.

8:05 p.m. update: The snow should start to pick up and begin to accumulate in earnest after 9 or 10 p.m. Our far north and west suburbs (6-12″ band on map at bottom of this post) should stay mostly snow through the night. The big question with this storm for the close-in suburbs and in the city is how much sleet mixes in from the southeast during the overnight hours, mainly after 1 a.m. or so. This is super tricky to predict when you’re right on the rain-sleet-snow line like we are. The simulated radar below (from the HRRR model) shows how things might evolve (blue is snow, pink is sleet, green and yellow are rain):

7:10 p.m. update: And our first significant storm of the season is underway. Well, if you count flurries and some light snow. That’s what we’re seeing intermittently across the area. With temperatures above freezing, roads should be just fine until at least 9 or 10 p.m., after which the snow should become steadier and temperatures colder.

7:00 p.m. update: For reference, here is our snow forecast accumulation map:

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