Winter storm to spread heavy snow from North Dakota to Virginia

The flakes are flying in Minnesota and North Dakota, where up to 10" of snow has fallen from an "Alberta Clipper" that is barreling southeastwards across the U.S. These type of storms, so-named because they originate in Alberta and clip along at a fast forward speed, typically bring the Midwest moderate amounts of fluffy snow that is relatively easy to shovel. The storm, dubbed Winter Storm Saturn by The Weather Channel and "Snowquester" by The Washington Post's Capital Weather Gang, is expected to bring a swath of 6 - 10" of snow from Minnesota to Virginia Monday through Wednesday, with Chicago expected to get 6 - 9", their biggest snow of the season. Once the storm moves off the coast on Wednesday, its strong winds will make coastal flooding a major concern for the Mid-Atlantic coast, particularly Delaware, on Wednesday and Thursday. The computer models are still showing quite a bit of disagreement on what the storm might do on Wednesday. The European model has been the most consistent model, and maintains that the storm will not bring heavy snow to New England. I would lean towards this solution at present. However, keep in mind that the latest run of the GFS model shows a more northerly track, with heavy snow falling along a swath of coast from Long Island, NY, to Boston, MA, Wednesday through Thursday. The exact position of the rain/snow boundary along the Mid-Atlantic coast is also quite uncertain. Washington D.C. could end up with mostly rain, and just 1 - 2" of snow, or get a 6+ inch dumping, picking up more snow from one storm than from the all the snowstorms from the past two winters, combined:

Reagan Nat'l Airport (DCA):
- Snowfall this season-to-date:  1.5"
- Snowfall all last season:  2"
- Last 5"+ snow event:  Jan. 26, 2011 (5")
- Last 10"+ snow event:  Feb. 9-10, 2010 (10.8")

Dulles Airport, Virginia (IAD)
- Snowfall this season-to-date:  5.3"
- Snowfall all last season:  3.7"
- Last 5"+ snow event:  Jan. 26, 2011 (7.3")
- Last 10"+ snow event:  Feb. 9-10, 2010 (9.3")

(Thanks go to Jonathan Erdman of TWC for these stats.) The Capital Weather Gang has an interesting article on historical March snowstorms in Washington D.C. In order for Winter Storm Saturn to crack the top-ten, it would have to dump at least 6.6" of snow on the nation's capital.



Coastal flooding a concern in the Mid-Atlantic
As the storm moves off the coast on Wednesday night, winds gusting to 50 mph will build waves of up to 15' and a 3 - 4' storm surge along the coast to the north of the center. Heavy rains will bring runoff down rivers that will act to increase water levels along the coast. The latest Forecast Discussion from the Mount Holly, NJ NWS office highlights the likelihood of at least moderate coastal flooding in Delaware during the high tide cycles on Wednesday afternoon and Thursday morning, with the possibility of major flooding. The latest storm surge forecast from the GFS model calls for a storm surge of around 3' at Lewes, Delaware on Thursday morning, which would bring the 8th highest water level on record to the coast. This is of concern due to the damage Hurricane Sandy brought in October, which weakened the dunes and left the coast more vulnerable to erosion. Sandy brought the 3rd highest water level on record to Lewes.

We'll have ongoing coverage this week of Winter Storm Saturn in our Winter Storm Section.

Jeff Masters