Overview: From the I-95 corridor, including the District, out into our northern and western suburbs, snow, sleet and freezing may have created messy, slick travel this morning - especially with most roads untreated. This wintry mix will gradually transition to heavy rain (1 to 2 inches possible) late this morning and afternoon, first along the I-95 corridor and eventually working its way towards our far western suburbs. Total snow accumulations before the changeover will probably be around 0.5-1.5” from east to west where there has been snow (but higher north and west of a line from Leesburg to Frederick).
Noon update: I’m a bit puzzled by this, but the National Weather Service has decided to extend the Winter Weather Advisory for the immediate metro region through 7 p.m. I’m puzzled simply because temperatures are above freezing at both Reagan National (35) AND Dulles airports (33) and plain rain is falling. Temperatures should continue slowly rising this afternoon - perhaps to 40 or so inside the beltway. Yes, caution should be exercised driving in rainy conditions and a few slick spots could remain from earlier snow/sleet on side roads, but frozen precipitation is over for the immediate metro area. Folks should be able to get out and about without much difficulty - just allow some extra time.
Well to the north and west, in Loudoun, Frederick and Carroll counties, and to the west, it’s a different story. Frozen precipitation (snow/sleet in western sections, sleet and freezing rain in eastern sections) continues with temperatures at or below freezing, and the winter weather advisory prudently continues through 6 a.m. Thursday. Icy travel will continue to be an issue, particularly in western sections of those counties into tonight. In eastern sections of these counties, a transition to plain rain is still possible this afternoon. Right now, the snow/mix line seems to run from just east of Frederick, Md. to around Purcellville, Va - snow falls west and north of that line, and a wintry mix to the south and east (until you get into the immediate metro area, where it’s plain rain).
11 a.m. update: A big push of warm air aloft ahead of the massive storm to our southwest is changing snow to sleet, freezing rain and just plain rain across the area. Reagan National was reporting light rain and 34 at 11 a.m., and Dulles light freezing rain and 32. Even normally colder places like northern Montgomery county and Leesburg are transitioning to sleet. Snow is confined to western Loudoun and Frederick counties, but even there it will changeover to a frozen mix by early afternoon. You’d need to get into western Maryland and West Virginia for this to be a snowstorm (with no changeover).
While we’re seeing this changeover occur, temperatures in the colder north and west suburbs could remain at or below freezing through early to mid-afternoon, so icy travel will continue to be a problem especially in places like Leesburg and Frederick and to the west.
10:00 a.m. update: In District, close-in suburbs, and most points to the south and east, snow has transitioned to sleet and freezing rain or plain rain. Temperatures are right around freezing in these locations. But to the west and northwest, snow, mixing with sleet at times, continues. Accumulations, so far, have been around 0.5-1 inch. I wouldn’t expect a lot more snow accumulation, but slick travel and temperatures at or below freezing will persist through noon or soon, and into the afternoon from Leesburg and Frederick to the northwest.
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