D.C. area forecast: Snow concludes, but frigid tonight

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4:20 p.m. update: The snow is finally ending in our far southern areas, with just a little lingering in southern Calvert and St. Mary’s counties. That will end before dark. Total accumulations across the region were generally 4 to 8 inches.  The cold is now the big story, per the update below from 3:25 p.m. For more on the forecast for tonight and tomorrow, as well as FedCast and SchoolCast, see our PM Update. (Scroll all the way down for our forecast through this coming weekend). This update concludes this live blog. Thanks for sticking with us all day.

Temperature Map

Temperatures: Latest D.C. area temperature map. See interactive map on our Weather Wall.

3:25 p.m. update: With the snow over except for our southernmost counties, the next big weather concern is tonight’s cold. Current temperatures are in the upper teens to low 20s with wind chills between around 5 and 10.

Overnight tonight, if skies clear out as expected, it will really allow temperatures to tumble. Lows may drop to near 0 in our colder suburbs to around 10 degrees downtown.  The record lows Tuesday are 4 in D.C. (from the Reagan National and 24th and M St. observing locations, from 1873), 6 at Dulles (from 1980) and 5 at BWI (from 1873).  The Dulles and BWI records have a chance to be challenged.

Even as winds gradually diminish, wind chills will likely be below zero at times overnight. This extreme cold means any slushy snow will freeze like a rock and untreated roads and sidewalks will turn icy. Stay tuned for our PM Update for more details on the forecast through tomorrow.

High resolution NAM model temperature forecast for 4 a.m. (WeatherBell.com)

High resolution NAM model temperature forecast for 3 a.m. (WeatherBell.com)


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.

3:00 p.m. update: Winter storm warning discontinued with the exception of Stafford County, Fredericksburg, and Southern Maryland (Calvert, Charles, and St. Mary’s counties)

2:50 p.m. update: A stubborn ribbon of snow continues from around Quantico to Fredericksburg extending east to the Bay. It may take until 4 p.m. or so to really taper off and/or move out.

2:27 p.m. update: I just spoke to Mark Richards, weather observer at Reagan National Airport, who said the snow total there was 3.8 inches. That brings the seasonal total to 23.1 inches.

2:15 p.m. update: The storm is now over for the entire region except for the area between Dale City and Fredericksburg extending east into southern Maryland, where snow should end northwest to southeast between now and around 3:30 p.m. or so.

1:55 p.m. update: The winter storm warning has been dropped for Loudoun, Montgomery and Howard counties as the snow has ended there.

1:45 p.m. update: From downtown D.C. and to the north and west, this storm is over. But it’s ripping snow in Mt. Vernon, Dale City, Waldorf and La Plata, where snow will continue to accumulate for the next 30 to 60 minutes, and probably a little bit longer closer to the Chesapeake Bay.

1:15 p.m. update: The storm’s final band stretching from around Annapolis through the District and into Manassas has put down some impressive snowfall rates – on the order of 1-2″ per hour. It has passed areas north and west of Baltimore to Rockville to Sterling, where the storm is now over. But it still has to come through our south and southeast suburbs from Fredericksburg into Southern Maryland, which should get 1-2 inches or so from the band.

12:55 p.m. update: Here’s a quick round-up of snowfall totals from readers:

Virginia: Fairfax County: 5 to 8 inches; Arlington 5 to 6 inches; Alexandria 5 to 6 inches; Manassas/Prince William County 5-6 inches; Loudoun County 5 to 8 inches; Stafford county and Fredericksburg 3 to 6 inches.

D.C.: 3.5-5 inches

Maryland: Montgomery County: 5-7 inches; Prince George’s county 3.5 to 6 inches; Howard County: 4 to 6 inches; Charles Co. 3-5 inches;

12:45 p.m. update: This storm’s final band is going to save our forecast in many areas – as the additional 1-2 inches or so it’s dropping is putting most spots in the immediate metro area near or over 5″.

12:00 p.m. update: The storm’s concluding snow band seems to have presented itself from around Baltimore to Leesburg – and some of the snow within this band is heavy. It’s slowly pushing southeast and should push southeast of the Beltway around 1 p.m. and into southern Maryland and the Fredericksburg, Va. area just after 2 p.m. The band may put down 0.5″ or so to the northwest of the Beltway. Inside the Beltway, another 0.5-1″ of snow is possible. South and southeast of the Beltway, another 1-2″ of snow may fall.

Roads around the region are still potentially hazardous in many areas. Here are some pics:

 

 

11:30 a.m. update: A word about the cold: at 11 a.m., the temperatures at Reagan National and Dulles airports were 19 and 16, with wind chills of 5. That’s remarkable for early March, and about as it cold as it gets. Today’s high temperatures in the 30s actually occurred at midnight (last night); had the arrival of the cold air been timed differently, this would’ve been one of the coldest days so late in the winter on record.

10:55 a.m. update: Predicting the snowfall along this storm’s northern edge has proven tough. In areas where snow had stopped in eastern Loudoun, central Montgomery and southern Howard counties, snow is now redeveloping some and picking up in intensity. Even as dry air to the north tries to push all of the snow south, there is still some moist air surging northward which is keeping the snow going intermittently. This will be the pattern into the early afternoon before the cold, dry air finally wins out and shuts down the snow from northwest to southeast. Snow totals so far are generally in the 3-6 inch range.

10:30 a.m. update: Snow continues to fall steadily along the I-66 corridor and to the south and southeast. But it’s become very patchy and light to the north. Some areas where snow stopped north of town may see it start and stop again intermittently, but steady activity and much additional accumulation is unlikely. The general trend of the snow should be to push southeastward and diminish through early afternoon. Here’s a cool timelapse of the snow from Capitol Hill:

9:50 a.m. update: For snow lovers, the radar shows something ominous: dreaded dry air. It’s streaming in from the northwest, cutting off the snow in northwest Loudoun and Frederick counties, and pressing southeast. It has the potential to end the snow a bit earlier than expected and may result in totals lower than forecast in quite a few areas, unless the snow can redevelop some. The NAM suggests 1″ of additional snow or less north of Rt. 50 and I-66 after around 10 a.m. and, based on radar, that may well play out. A good chunk of the metro region may see snow really taper between 11 a.m. and noon. There’s a chance some snow may try to fill back in through early to mid-afternoon, but we can pretty much rule out the high-end of our forecast range and any boom scenario.

9:30 a.m. update: Snowfall totals are generally now into the 2.5-5 inch range as moderate to heavy snow continues (though dry air is intruding and cutting off snow in our northwest suburbs). Roads are snow-covered and slick. Travel is discouraged, but if you must drive, take it slow, keep a larger than usual following distance and apply brakes gently and gradually. Some pictures:

 

 

9:05 a.m. update: For the next two hours, we’re in the prime of this storm – with moderate to heavy snow at times, gusty winds, and very cold temperatures (temperatures 16 to 22 degrees around the region). However, there are signs dry air pushing in from the northwest is starting to cutoff the snow in northern Frederick County (Md.) towards the Pennsylvania border. So it’s going to be hard to see snowfall totals much above the low end of our forecast range (5-9″) in the immediate metro region and northern suburbs. The NAM model only simulates 2-3 more inches of snow for the area, with little to no snow falling after noon. Some other short-range models suggest some light snow could linger through mid-afternoon. The bottom line is that most of the accumulation from this storm will occur before the noon hour, except in our far southern suburbs where additional accumulation may continue through 2 or 3 p.m.

8:35 a.m. update: Snow totals are now into the 2-4 inch range in many locations in the region as the wind-blown snow falls at a steady clip. Some photos:

 

 

 

 

8:10 a.m. update: This is a serious winter storm, hitting its stride. Snow rates are picking up, winds (gusting to 25 to 30 mph) are blowing the snow, and visibilities are generally below one mile. Temperatures have also crashed into the high teens to low 20s in most places (17 at Dulles, and 26 at Reagan National, warmer than just about anywhere else at 8 a.m.) – unusually low for early March. Roads by and large are snow-covered and travel is difficult. The bust potential for this storm is starting to evaporate. Some short range models keep the snow going until around 2 to 4 p.m. (north to south), although the steadiest and heaviest snow is likely between now and noon.

7:45 a.m. update: Snow totals – so far – are generally in the 1-3 inch range with some isolated higher amounts. The heaviest totals are in some of our northern suburbs where the snow started earlier. Even though the snow will end there first and it will not fall as heavily (compared to locations south of D.C.), they look on track to reach the low end of our forecast totals, at least. And, for the moment, a heavy band has developed in northern Frederick, Carroll and Baltimore counties. Another heavy band stretches from central Virginia (around Charlottesville) into southern Maryland. Elsewhere snow is falling at a more light to moderate, but steady slip (with an occasional heavier burst).

7:20 a.m. update: In addition to the snow and cold temperatures, we have wind. At 7 a.m. winds were sustained around 20 mph at both Reagan National and Dulles Airports, gusting to near 30 mph. At Dulles, the wind chill was just 3 degrees.

6:50 a.m. update: Snow is falling steadily across the region and sticking to roads. The transition from sleet to snow has now reached our southern areas around Fredericksburg and southern Maryland. Reports are that roads are slick so stay off them if you can. Regarding concerns about a snow forecast bust inside the Beltway (including the District) and points south, radar and short-term model forecasts indicate our snow forecast is on track (and we should reach 5-9″ around D.C., and 7″+ in our southern suburbs). Because the intensity of snowfall is less in northern areas, a bust is possible there but – per our 5:15 a.m. update – because it’s very cold and the snow is fluffy, it will tend to stack up and could reach the low end of our forecast range (5 or 6″). Already there are reports of over 2 inches in parts of Montgomery County.

 

6:20 a.m. update: Temperatures continue their steady decline. Dulles is already down to 23 degrees, while Reagan National has fallen to 30. You can get a decent sense from radar where the heavier snow (and/or mixed precipitation which will change to snow) is setting up. It’s generally south of I-66 and Rt. 50 coincident with the zone we’re forecasting the most snow (scroll down to the detailed forecast for today to see our snowfall map).

Radar at 6:10 a.m. (RadarScope)

Radar at 6:10 a.m. (RadarScope)

5:40 a.m. update: Snow continues to fall steadily and accumulate on all surfaces as temperatures fall back into the 20s pretty much everywhere in the metro region.  The exception is in southern Maryland and Fredericksburg, Va. and south where sleet and/or rain is still falling.  As the cold air continues to seep south, the mixed precipitation there should transition to snow by 7 a.m. or so.  We still expect the heaviest snow totals in our southern suburbs. While the snow is starting later there, it should fall more intensely and for a longer duration than points north.

 

5:15 a.m. update: Short-range models this morning simulate snow totals struggling to reach the low end of our 5-9″ range in our far northern suburbs, as there is a fairly pronounced cutoff due to cold dry air coming in.  Referring to our snowfall forecast map (scroll down below our forecast for today), areas which I’d put on a bust watch stretch along a line from northern Montgomery County to around Baltimore city and points north.  Having said this, as the snow will be very powdery in these areas (high snow to liquid ratios), it will tend to stack up and accumulate readily…so a bust is not a guarantee. I do think it will be difficult to reach higher end totals in these areas.

The latest short-term model snowfall forecasts (which assume 10:1 snow to liquid ratios) are below.

RAP model snowfall forecast (WeatherBell.com)

RAP model snowfall forecast (WeatherBell.com)

HRRR model snowfall forecast (WeatherBell.com)

HRRR model snowfall forecast (WeatherBell.com)

High resolution NAM model snowfall forecast (WeatherBell.com)

High resolution NAM model snowfall forecast (WeatherBell.com)

4:55 a.m. update: Mixed precipitation has finally changed over to mostly snow except in our far southern suburbs (still sleet around Fredericksburg and southern Maryland).  The snow, falling on top of a layer of sleet, is quickly accumulating on all surfaces according to reports.  Temperatures are in the upper 20s to around freezing.

 

 

Today’s Daily Digit

A somewhat subjective rating of the day’s weather, on a scale of 1 to 10.

7
Can’t get enough snow. A lucky 7 honoring the potential for 7 inches.

Express Forecast

Today: Snow, heavy at times this morning, tapering in the afternoon. 20s.

Tonight: Clear and extremely cold. Lows 0-11.

Tomorrow: Mostly sunny, cold Highs: 23-29.

FORECAST IN DETAIL

From 4 a.m.: The combination of heavy snow and falling temperatures makes travel extremely difficult this morning. Best to stay in.  Snow gradually tapers off this afternoon, but seriously cold air follows in the wake of this storm with single digit temperatures tonight.  Even Tuesday we’re stuck in the 20s and temperatures remain below normal for the balance of the upcoming week.  It’s March now, but mother nature isn’t paying one bit of attention to the calendar.

Today (Monday): Snow through the midday hours, moderate to heavy times. Total accumulations should be in the 5-9 inch range from the District and points north, but 7-11 inches are possible just to our south, where a heavy band may set up and linger into the early afternoon.  A little thunder could accompany the snow at times.

After the snow ends in most areas by mid-to-late afternoon, a few breaks in the cloud cover are possible. Temperatures gradually fall through the 20s during the day, possibly even dipping into the teens in our colder western and northwest areas. Winds are from the north at 10-15 mph. Confidence: Medium

Capital Weather Gang snowfall forecast update as of 11:00 p.m. 3/2/14

Capital Weather Gang snowfall forecast update as of 11:00 p.m. 3/2/14

Tonight: Clearing skies and bitter cold.  Lows range from near zero in some of our colder suburbs to around 10 downtown.  These readings are some 25 degrees below normal and may challenge records at Dulles (6 from 1980) and BWI airports (5 from 1873). Winds from the north diminish to around 5 mph late at night. Confidence: Medium-High

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…

Tomorrow (Tuesday): Sunny but unseasonably cold. Highs range from the low-to-mid 20s in our colder suburbs to the mid-to-upper 20s downtown. Winds are light from the north around 5 mph. Confidence: Medium-High

Tomorrow night: Some increase in clouds and not quite as cold, but still well below normal.  Lows range from near 20 downtown to the mid-teens in the colder suburbs.  Light winds. Confidence: Medium-High

A LOOK AHEAD

Wednesday and Wednesday night are partly to mostly cloudy.  With cold high pressure parked to the north, it remains on the chilly side.  Highs Wednesday range from 31-36 (northwest to southeast).  Overnight Wednesday, low temperatures moderate a little more, from near 20 in the colder suburbs to the upper 20s downtown. Confidence: Medium-High

Temperatures trend somewhat less cold Thursday and Thursday night although low pressure passing to our south and then east could throw back some rain and/or snow showers.  There’s probably not enough precipitation to cause major disruptions, but we’ll keep an eye on it.  Highs range from 35-40, with overnight’s lows in the upper 20s to low 30s.  The overall period is more cloudy than not.  Confidence: Low-Medium

Friday may see a return of milder air and a great chance to finally break through back into the 40s – let’s say mid-to-upper 40s.  There’s an outside chance of a rain shower, but it looks mostly dry at this point.  Partly cloudy Friday night, with lows near freezing in the colder suburbs to the mid-to-upper 30s downtown.  Confidence: Low-Medium

Another strong cold front likely pokes through the region over the weekend – Saturday or Saturday night.  The timing is uncertain, but rain showers are possible and we can’t even rule out mixing or changing over to snow for a time.  Highs Saturday are in the 40s, with lows Saturday night back into the 20s to near 30.  On Sunday, we probably clear out, but it’s chilly with highs only around 40.  Confidence: Low-Medium

Also on Capital Weather Gang

Live updates: March winter storm hits D.C. area