Most Read: Local

Posted at 01:00 AM ET, 03/06/2013

The start of Snowquester: Tuesday night live blog; snowfall forecast increased

* Winter storm warning entire area thru very early Thurs. a.m. *

Overview: The first band of precipitation is moving in from the season’s first major winter storm. Track the latest developments and forecast updates in this live blog.

Revised snowfall total projections (upward)! We are now forecasting 5-10 inches inside the Beltway, 7-14 inches in the western suburbs, 10-18 inches in far western areas towards the Blue Ridge, and 2-6 inches in the far eastern suburbs. (Revision made at 11 p.m., scroll to bottom of post for earlier snowfall forecast)


Capital Weather Gang’s snowfall forecast, second call, issued 11 p.m. March 5.

Useful links: Storm talking points | Storm timeline, impacts and FAQs | Thundersnow? | The structure of a snowflake | The past as a predictor | March snowstorm history


In it for the long haul? The RAP model simulates snow still falling into the D.C. metro region at 5 p.m. tomorrow. This may be aggressive as some models suggest snow will wind down earlier. We shall see.
1:00 a.m. update: Some final key points before closing out this live blog for the night:

* Snow will tend to increase in intensity overnight with falling temperatures to around freezing. Snow will gradually stick to grassy surfaces and ultimately roads.

* Snow may well be falling very heavily around the morning commute time, but traffic will be light due to likely widespread school and business closures.

* Periods of snow, sometimes heavy, are likely at least into the afternoon hours Wednesday, although it’s possible there may be a lull in the activity should a dry slot move into the region for a brief time (but we think it may stay south).

* In addition to poor driving conditions, the other main hazard from this storm will be possible power outages from the heavy wet snow. Also, older adults should be careful shoveling the snow and seek assistance if necessary.

We will resume coverage around 4:30-5:00 a.m. In the interim, we will sprinkle some Twitter updates so follow our feed above. Also, feel free to continue the lively discussion in the comment section below.

12:45 a.m. update:Snow is coating the trees in Charlottesville (see the pic below). Not far to the north, a report from the National Weather Service reports 1.8 inches already in Opal, Va. The heaviest snow is still to the south but on its way north. Once it gets going, moderate to heavy snow may continue well into tomorrow during the day according to short-range models .

12:30 a.m. update: It seems that it generally takes about 30-60 minutes for snow to start sticking to grassy areas once precipitation transitions from a mix to all snow. Southeast of town, west of La Plata, a coating on grassy areas is apparent in this Tweet from @mdbellis. For snow to begin sticking on roads, it may require an additional hour.

12:20 a.m. update: It’s amazing how quickly the snow is already piling up in places just to our south. Twitter follower @fluffydaniel reports 3/4 inches already in Centreville. AccuWeather says down in Roanoke, 2 inches are on the ground. The view of Snowquester from space taken at 12:01 a.m., below, is pretty incredible.


(NASA)

12:00 a.m. update: Widespread reports of snow are now coming in around the District. Amazingly, the ground is already covered around Warrenton, made evident by a photo posted to Twitter. Commenter “Dizzzy” reports 1.5 inches in Linden (just east of Front Royal) at an elevation of 1,500 feet. Places like this could get 15 inches or more.

11:55 p.m. update: Pressures are falling rapidly off the coast of the Carolinas, a sign the storm is strengthening.

11:50 p.m. update: Given the higher amounts now forecast, it means a larger fraction of the region will receive enough heavy, wet snow to potentially accumulate on trees and powerlines and lead to outages. Before heading to bed, charge your portable devices, locate your flashlights, and make any other outage preparations.

11:45 p.m. update: Very cool: Interactive map of U.S. snow cover over time.


11:40 p.m. update: Precipitation moving into the immediate metro region (inside the Beltway) at the moment is rain or a mix according to reports, but it should fairly quickly turn to snow (within an hour or so of onset) as it becomes heavier.

The National Weather Service Storm Prediction Center is highlighting the potential for heavy snowfall to develop around 1 a.m. in west central Virginia and move northeast into the Washingotn, D.C. area by 3 a.m. Snowfall rates of 1-1.5 inches per hour are likely SPC says. Expecting driving conditions in pre-dawn to sunrise hours to become hazardous.


Revised National Weather Service snowfall map. See big.
11:25 p.m. update: The National Weather Service has increased its snow total forecast and is now calling for 6-12 inches in the immediate metro area. Notably, it has expanded its winter storm warning to cover areas east of the city, including Southern Maryland where it forecasts 6-10 inches.

11:15 p.m. update: D.C. schools have announced they will close tomorrow, the first of many no doubt. Snow is falling in most of Fairfax county now according to reports - in a few spots mixed with rain/sleet at the onset. Within the next 30-45 minutes or so snow (or briefly mixed precipitation) should be falling across the entire region.

10:55 p.m. update: Snow has reached Centreville, Warrenton, Fairfax, Purcellville, Annandale and as far north as Bethesda according to reports. In some spots, rain and/or sleet mixes in but only very briefly.


(StormVistaWxModels.com)
10:45 p.m. update: Wow. The GFS model has come in with between 1.75 and 2” of liquid equivalent in the D.C. area which would convert to 8 inches to around a foot (or even a bit more) assuming a conservative ratio of 5-8 inches of snow per inch of liquid. Suffice to say, we will be upgrading our snow total forecast shortly. We may be staring at a historic (top 5-10 events) March snowstorm. Stand by.

10:35 p.m. update: Snow (sometimes mixed with sleet) now being reported in West Springfield, Winchester and Chantilly - edging closer to the Beltway and should move on in within the next hour. The GFS model is coming in and it’s also “going big” with snow totals.

10:10 p.m. update: D.C., up to this point, is not alone in experiencing subpar snow totals this winter. Snowfall has been below average in many parts of the U.S. Check out this neat Interactive Graphic.


Simulated 5 a.m. radar
10:05 p.m. update: Some of the high resolution, short range models suggest very heavy snows are possible in the pre-dawn hours (no doubt, this pleases school kids and Federal workers). One to two inch per hour rates and even thundersnow cannot be ruled out as this storm starts to really crank.

9:50 p.m. update: Commenter Captains2012 writes: “Here in Harrisonburg it is a full on snowstorm with nearly an 1/2 to a full inch on the ground and the roads are covered.”

9:45 p.m. update: A wider view of the radar shows quite the impressive swirl, and this storm is just in the early phases of organizing. Reports of snow are now coming in from around Stephens City and Front Royal.


Radar wide view at 9:40 p.m.

9:35 p.m. update: A report of snow has come in from Dale City. Weather enthusiasts on the AmericanWx.com bulletin board report ripping snow in Staunton and south of Charlottesville.

9:30 p.m. update: Reports indicate snow in Fredericksburg and La Plata (in Charles county). Also, the NAM model indicates most of the event may well be in the form of snow in the immediate D.C. area and to the west (with not much rain). If it’s right, that would favor the high end of our accumulation ranges. The model indicates about 1.75 inches of liquid equivalent as a storm precipitation total, which assuming a conservative 5 to1 snow to liquid ratio, would produce 8-9 inches of snow in the District


NAM model simulation of precipitation through 7 a.m. (StormVistaWxModels.com)
9:20 p.m. update: The latest NAM model indicates the potential for substantial snows overnight, with several inches on the ground by morning in most locations and perhaps up to 6 inches in the colder western suburbs.

9:05 p.m. update: Precipitation is rapidly moving into the region from the south, with radar indicating activity into southern Fauquier and Prince William county. A mixture of snow, sleet and rain has been reported by Twitter followers in King George, Caroline and Charles county. The fact that locations to the south and east are already reporting snow portends perhaps the changeover from mixed precipitation to snow will occur very quickly in the D.C. metro region.

From 9:03 p.m., earlier snow projection (no longer valid):

As a reminder, we’re forecasting generally 3-8 inches inside the beltway and just east of town, with 6-12 inches expected in our western suburbs. Precipitation is set to begin across the region over the next couple of hours, likely beginning as a mix but changing to snow as the night wears on.

By  |  01:00 AM ET, 03/06/2013

Categories:  Latest, Winter Storms

 
Read what others are saying
     

    © 2011 The Washington Post Company