Spring storm lays down several inches of snow

* Winter weather advisory through 8 p.m.  | Snow total reports from NWS | Gallery: Spring snow in Washington *


Radar & lightning: Latest D.C. area 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: A strong upper level disturbance passing through the area today will bring snow, moderate to even heavy at times. Most snow accumulation will occur on grassy areas, but slushy roads and sidewalks are possible during heavier snow bands. Snow will keep going into this evening as the ocean storm starts to develop and additional moisture feeds into the area.

Key points:

  • Along and west of I-95, total accumulations of 2-5 inches are possible on grassy areas – but a little snow could build-up on roads at times (especially this morning and this evening in colder areas west and north of the city).
  • Isolated amounts over 5 inches are possible in the mountains/higher terrain.
  • East of I-95, generally a coating to an inch or two are most likely, mainly on grassy areas.
  • Snow may reduce visibilities and cause some slick spots during the evening commute, especially after 6 p.m. as daylight fades
  • Snow probably winds down between 7 and 10 p.m. tonight from west to east.
  • Temperatures near and below freezing this morning should rise above freezing along and east of I-95 this afternoon, limiting accumulation.  However, colder areas west and northwest of the city may remain near freezing.

UPDATES

4:40 p.m.: The immediate metro region sits in the gap between bands of snow in our far western and eastern suburbs.  This gap should close between 5 and 6 p.m., with snow re-developing.  This is our last update in this post.  Stay tuned for our PM Update, which should be posted at 5 p.m. 

4:15 p.m.:  The dry slot, which temporarily stopped the snow inside the Beltway and to the south and east, has pushed about as far north and west as it’s likely to reach.  Over the next hour or so, the snow band in our western suburbs is likely to start coming back east and may well merge with an area of snow surging northward out of southern Maryland.  Areas along the I-95 corridor and to the east should see snow picking back up around 5 p.m.

At 4 p.m., Reagan National Airport had overcast skies and a temperature of 36.  The 1.6″ of snow through 2 p.m. is a daily record.  Dulles Airport, which the dry slot may not affect (but snow will end earlier than places to the east), still had light snow and the temperature was 32.  CWG’s Ian Livingston points out if Dulles stays below 34, it would be the coldest high so late in the season on record and would be the latest day with a high of freezing or below if the temperature does not go above 32 (the previous latest such date was March 20, 1965).

3:40 p.m.: Even though the dry slot has ended snow inside the Beltway and to the south and east, a heavy band of snow has set up from Gainesville, Va. through Reston and Rockville into Columbia, Md. and ultimately to around Baltimore.  This band may push a bit farther to the north and west before starting to pivot back to the east – gradually bringing back the snow where it had cut off…

3:15  p.m.:  A dry slot is invading the region, cutting through the District and pushing northwest.  It may not reach our western and northern suburbs outside the Beltway.  But it will shut off the snow for an hour or so  inside the Beltway and to the south and east.  Snow should then pivot back towards the east by around 5 p.m., with snow picking back up everywhere.

2:35 p.m.: Through 2 p.m., Reagan National Airport had received 1.6″ of snow from this storm.  The total snow this March is now 12.6 inches, making it the 5th snowiest March on record, and it’s still snowing…

2:15 p.m.: Roughly 1-3 inches of snow has fallen across the region, with the heaviest amounts west and southwest of the District.  At 2 p.m., snow continued moderately across the metro region, with temperatures near freezing northwest and west of the Beltway, and slightly above freezing elsewhere (35 at Reagan National, 31 at Dulles).  Although snow is falling at a good clip and visibilities are just 0.5 mile in some locations, snow is not accumulating much.  Roads are mostly just wet although there are reports of some slush build-up on side roads in Loudoun, Fauquier, and Stafford counties.  Radar shows a bit of a dry slot working towards the region from the southeast – that may result in snow decreasing in intensity or even stopping for a time in the metro area – perhaps in the 3 to 4 p.m. timeframe.  However, short-range models show it quickly filling in as the coastal storm gets going and moisture surges back into the region.

1:15 p.m.: Snow continues falling throughout the region, with temperatures hovering near freezing west and northwest of the Beltway and just above freezing elsewhere (31 at Dulles and 35 at Reagan National at 1 p.m.).  Snow is generally light, but there is a moderate band from near Dale City  north to around Great Falls and Potomac – which is more or less stationary. Except where snow is falling at least moderately, melting exceeds accumulation.  In other words, snow won’t pile up unless it’s falling somewhat intensely.  That should be the case for the next few hours.

12:40 p.m.: How much more snow? Short term models keep the snow going through 8-10 p.m. tonight, but the high March sun angle and temperatures near to slightly above freezing means snow may well melt before it can accumulate this afternoon, except when it’s heavy.  The RAP model, shown below, suggests we could get another 1-3 inches before the snow shuts off.  However, taking into account melting, I’d say another 0.5-2″ of snow is more likely.  The next good window for accumulation should be after 5 p.m. although some modest accumulation could occur in any heavy bands that cycle through in the mean time.

RAP model total snow accumulation forecast (11 a.m. to 10 p.m. tonight) (WeatherBell.com)

RAP model total snow accumulation forecast (11 a.m. to 10 p.m. tonight) (WeatherBell.com)

12:10 p.m.: Snow continues falling steadily, although the intensity has diminished ever so slightly in the last hour.  At noon, Reagan National and Dulles airports were reporting light to moderate snow.  Visibilities had increased to 0.5-0.75 miles from 0.25-0.5 miles last hour.  Accumulations so far are mostly in the 1-2 inch range, although a few locations to the southwest have 2-3 inch totals.  At this hour, snow is struggling to accumulate on paved surfaces.  That will continue to be the case through mid-afternoon as temperatures increase a bit and the intensity of snow eases.

Via Ian Livingston, Dulles Airport has picked up 1.4 inches (as of 11:40 a.m.) and now has 50.4″ of snow for the season.  That’s third most on record (since 1963), passing the snowy winter of 2002-2003 on the list.

Here are some more snow photos:

11:15 a.m.: Temperatures are creeping up, now 30 at Dulles and 34 at Reagan National Airport, but snow continues at a moderate clip with visibilities just a quarter to half mile.  Main roads are mostly just wet (thanks to the high March sun angle), although there are reports of slush on bridges and overpasses on I-95 south of the Beltway (where there has been some heavier snow).   Side roads and sidewalks – especially north facing and/or shaded – have some slush, especially in our colder areas.

We should continue with steady snow into the early afternoon but the little road accumulation we have should diminish as temperatures rise further.  Short-range models hint snow decreases some in intensity mid-to-late afternoon before picking up again towards early evening.  Here are some more pics (below).  Interesting fact: it also snowed (about this amount) on March 25 last year (see the first photo).

10:25 a.m.: Both Reagan National and Dulles Airports were reporting moderate snow with visibilities of just one quarter to half a mile at 10 a.m.. Temperatures range from 29 at Dulles to 33 at Reagan. Around the region, we’re getting reports of generally 0.5-1″ of snow already, on car tops and grassy areas for the most part. But Dale City to around Fredericksburg, I’m already seeing some reports of 1-2″, where heavy bands have set up and roads are reportedly slick. Radar shows moderate bands of snow lined up right along and west of I-95 where snow totals will continue to climb this morning.

10:00 a.m.: Based on radar and short-term models, we have increased our snowfall total forecast in most areas.  See our map below.

Capital Weather Gang revised snow total forecast map

Capital Weather Gang revised snow total forecast map

I should emphasize these are totals on grassy areas as opposed to roads.  Also, the D.C. urban core (downtown to around south Arlington and Alexandria), may struggle to get to 2 inches due to melting… but with snow falling steadily for a good part of the day, most of our colder suburbs should get at least 2 inches. The best chance of 4 or 5 inch totals are west of the Beltway.

Also on Capital Weather Gang

D.C. area forecast: Snow today delivers light accumulation, windy tomorrow with warming starting Thursday