D.C. area forecast: Quick snow this morning, cold into unsettled weekend

11:50 a.m. update: Snow is now rapidly concluding west of I-95, and should be over everywhere in the region by 12:30 p.m. Winter storm warnings and winter weather advisories have been dropped. We’ll see partial clearing this afternoon, which should promote some melting (highs 34-38)… Scroll down below for our thoughts on a re-freeze this evening (10:40 a.m. update). This is our last update. Stay tuned for a short write-up about what went right and wrong with this forecast by mid-afternoon. Thanks for staying with our coverage. – Jason, CWG

11:35 a.m. update: Back edge of snow continues to advance eastward and will end across area in the next hour. Snow is now ending in western Fairfax and western Montgomery counties, and should push east/northeast of I-95 by noon.

11:20 a.m. update: We’ve received a ton of reports of snowfall totals (via Twitter and Facebook): As far as I can tell, here’s a good overview of totals (though it’s still snowing in many spots): 0.5-2″ in D.C., 1-3″ in Fairfax County, 2-5″ in Loudoun, 2-4″ in Montgomery County, 3-6″ in Frederick County, and 1-2″ in Prince George’s County.

11:00 a.m. update: We can see the back edge of the snow pushing into western Fairfax and western Prince William counties. In Loudoun and northern Fauquier counties, this storm is mostly over. It will end from southwest to northeast over the rest of the area over the next hour or so, with little additional snow accumulation.

10:40 a.m. update: Do we need to worry about a refreeze tonight and will the p.m. commute be affected? The entire area will drop below freezing tonight, but with snow ending by early this afternoon, most roads should have time to get cleaned and/or dry out. Where they don’t, there could be some slick spots after dark, especially in the colder north and west suburbs. I don’t expect major problems and most areas should be in good enough shape for on time school Wednesday – although a delay or two in Loudoun and Frederick county wouldn’t shock me.

10:10 a.m. update: Radar shows the final (sort of) meaningful snow band entering the region, which will come through over the next hour. 

Here are some nice (some humorous) photos from around the region:

9:40 a.m. update: When does it all end? We’re already seeing the intensity of snow decrease, although it may pick up a bit (especially southern areas) as one more band to the southwest moves through between 10 a.m. and 11 a.m. After 11:00 or 11:30 a.m., it will really taper, and end everywhere by between noon and 1 p.m. Given temperatures from 32-34 across the area (warmest in the city), generally less than 1″ additional accumulation is likely.

While there hasn’t been much accumulation, check out this beautiful video of snow at the Capitol from @adamwells on Twitter (via Instagram):

9:15 a.m. update: As some of the heaviest snow steaks off northeast of the area and mostly light to moderate snow remains to the southwest (to come through over the next couple hours), the National Weather Service has downgraded the winter storm warning to a winter weather advisory south and east of Loudoun and Montgomery County. It has decreased its snow accumulation forecast from 3-6″ to 1-3″ in these areas, appropriately (although even that may be generous in some urban areas).

8:50 a.m. update: A pretty solid band of moderate snow is moving through now, but there’s not much behind it. So the intensity and accumulation will start to wane from 9:30-10:30 from southwest to northeast. Some lighter snows are possible after that, but this should start to wind down between 11 and noon.

The snow is certainly pretty, and good for snowballs. Here are some pictures from Twitter around the region.

 

 

 

 

 

 

8:30 a.m. update: Based on reports, about 1-3″ of snow has fallen in DC’s north and west suburbs. We should probably expect another 1-2″ (even downtown may get an inch if a heavy band to the west holds together) but I don’t see a “boom” scenario for many (over 5″ totals) as the storm is rapidly moving northeast. The precipitation is already winding down around Charlottesville. 8:05 a.m. update: A healthy snow band is now entering the region from the southwest…should help with accumulation in some of the snow deprived areas described below.

 

7:50 a.m. update: For snow lovers in south Arlington, Alexandria, downtown D.C. and the south and eastern suburbs, this storm has the potential to disappoint. The warmer than expected temperatures coupled with snow bands that haven’t been particularly heavy are making accumulation challenging. (Yes, there are some parallels to Snowquester). The next three hours are pivotal: radar shows some moderate snow to the southwest moving northeast – but my gut is that Reagan National struggles to break the 2″ snowstorm drought. After 11 a.m., the precipitation will start to gradually wind down. North and west of the city (and even in NW D.C.), our forecast of 2-5″ looks fine.

7:27 a.m. update: The difference in the scenes between the western suburbs and downtown D.C.- due to slightly warmer temperatures – is striking. Case in point, this tweet:

But with the snow becoming steadier, the landscape should gradually turn more wintry even downtown. In northwest, D.C. – in Cleveland Park – Ian Livingston has video of it turning snowier:

7:14 a.m. update: Many areas which had been reporting sleet are now reporting snow with accumulation beginning; however, in some of the milder spots snow/sleet is not yet sticking and it will take a bit longer for accumulation to occur. In these areas, mostly in the urban core (downtown, Crystal City, Reagan National), this will cut down on snow totals a bit; but if heavier bands come through, that would help overcome the higher temperatures.

In far western areas towards the mountains, already 1-3″ of snow has fallen. WUSA’s Howard Bernstein reports 2″ in Luray, and 3″ in Smithsburg, Md. (in just 100 minutes).

 

6:52 a.m. update: Snow and/or sleet has now enveloped much of metro region, with many reports of roads quickly getting covered, especially west and northwest of the District. In the District and south and east, temperatures will fall to freezing quickly, and snow/sleet should also begin sticking to roads.

 

 

Here’s a great winter storm resource from the National Weather Service with nice tables and maps showing the range of snowfall possibilities: Winter Weather Page. They have a lower end of around 2″, and a high end of around 8″ today.

6:35 a.m. update: We need to emphasize precipitation moving in is HEAVY and conditions will deteriorate very rapidly over the entire metro region over next 30 minutes – with accumulation on roads. Now is not a good time to head out.

6:30 a.m. update: Sleet and snow continues its progress into the metro region with a mixture of reports…more sleet to the south and east of town, more snow to the north and west. The transition from sleet to snow will be rapid, and precipitation will fall heavily in little time. Reporting precipitation through 6:30 a.m.: Oakton, Reston, Kensington, Waldorf, Herndon, Rockville, Fair Lakes and more! Everyone should be precipitating by 7 a.m.

6:05 a.m. update: Mixed precipitation has made it into Springfield and Lorton and will arrive inside the Beltway before 7 a.m. Although you may sleet and/or rain initially, it should change to snow fairly quickly. Towards the mountains, it continues snowing heavily in Martinsburg (1″ already) and Winchester, and we just got a report of the first flakes in Leesburg.

 

5:33 a.m. update: As precipitation continues to streak into the area (snowing in Martinsburg, Luray and Front Royal, heavy sleet at Chesapeake Beach), a quick look at models from overnight along with regional radar indicate this storm isn’t missing us and we should be able reach forecast totals without much problem. Temperatures are a bit warmer than forecast in the District, but will fall quickly to freezing once precipitation begins in earnest.

5:11 a.m. update: Sleet and snow is rapidly developing to the west and southwest and should move into the immediate metro region in the next one to two hours.

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Today’s Daily Digit

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

3
Some inflation for those who love snow, but keeping low to respect dangers and disruptions

Express Forecast

Today: Snow! Highs: Low-to-mid 30s.

Tonight: Mostly clear and very cold. Lows: Teens to near 20.

Tomorrow: Partly to mostly sunny, cold. Highs: Upper 20s to low 30s.

FORECAST IN DETAIL


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.

A burst of mainly snow this morning could ambush the commute before ending fairly quickly during the midday hours. We still favor the 2-5″ range for most, but we’ll need to watch closely as the fast-moving event unfolds. Otherwise, conditions calm down later today and stay that way through the balance of a very cold work week, with a combination of big high pressure and snow cover on the ground sending overnight lows into the teens. A new storm approaches this weekend, possibly triggering mixed precipitation on Saturday as temperatures try to briefly warm.

Temperature Map

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

Today (Tuesday): Light snow may be mixed with sleet initially as it expands over the area from the south and west between approximately 5-7 a.m. We could then see a period of moderate to heavy snow over the area around 7-11 a.m., which could quickly accumulate on roadways faster than road crews can keep up. Snow likely begins to taper from west to east by late morning, and most of the snow should be done by early afternoon, with perhaps even some sunshine breaking out by mid-to-late afternoon.  Highs don’t escape the low-to-mid 30s, and temperatures could dip to the upper 20s during the snow. Light breezes from the north at 5 to 10 mph. Confidence: Medium

We expect metro area snow accumulations generally in the 2-5″ range, but with some risk of either lower or higher amounts. See the map below for more details.

snow_chances_12-10-13-3

Temperature Map

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

Tonight: Mostly clear skies and chilly as snow cover helps enhance the impact of the arriving cold air mass.  Lows in the outer north and west suburbs are aiming for low-to-mid teens, while toward the District and points east/south should see teens to around 20F. Light winds from the west and northwest at around 5 mph.   Confidence: Medium-High

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

Tomorrow (Wednesday): Mostly sunny and chilly as highs struggle to reach the freezing mark.  Highs range from the upper 20s to low 30s with light winds from the west.  Confidence: Medium-High

Snow Potential Index

A daily assessment of the potential for at least ~1″ of snow in the next week, on a 0-10 scale.

8 (↑) Many areas could pick up enough snow just today to match or exceed last winter’s entire total.

Tomorrow night: Another mostly clear night with very cold temperatures.  Lows dip into the teens across the suburbs to near 20 downtown.  Confidence: Medium-High

A LOOK AHEAD

Thursday and Friday are cold days with high pressure overhead. Partly to mostly sunny skies are the only offset to chilly temperatures mainly in the upper 20s to lower 30s for highs.  Lows Thursday night are in the single digits and low teens in the outer western to northwestern suburbs, while mainly in the teens to near 20 in the city to points south and east.  Friday night finds some clouds moving back into the scene with lows in the 20s.  Confidence: Medium-High

The weekend is a tricky one as yet another storm system targets the mid-Atlantic area.  The current thinking favors a mix of snow/sleet/freezing rain on Saturday, perhaps starting in the morning, turning to all rain by afternoon or evening before ending late at night. But exact timing and storm track are of course fairly uncertain at this stage, and as you can imagine, minor changes in either could make big difference in what kind of weather we see. Saturday temperatures may be mostly in the 30s before warming to the 40s late in the day and then cooling back to the 30s and 20s late Saturday night. Sunday should see variable clouds and temperatures turning colder again with highs in the 30s.   Confidence: Very low

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