Heavy snows fall from Chicago to Virginia

An intensifying winter storm has moved off the coast of Virginia this morning, and will bring heavy rain and snow, strong winds, and coastal flooding to most of the Mid-Atlantic and New England coast over the next two days. Rain is mixing with snow in the Washington D.C. area, where 4 - 8" of snow is expected today, down from earlier forecasts of 8 - 12". According to The Capital Weather Gang, today's snowstorm needs at least 6.6" of accumulation to crack the top-ten list for biggest March snowstorms in D.C.; the biggest March snowstorm in D.C. history was 12" on March 27 - 28, 1891. Snowfall amounts of up to 15" have already fallen in western Virginia near Shenandoah National Park, as of 10 am EST Wednesday, and thundersnow was reported near Richmond, Virginia. Snowfall amounts of 12" were observed at Valparaiso, Indiana on Tuesday, and Chicago is digging out from 9.2"--the biggest March snow in Chicago in a calendar day since 11.5" fell on March 2, 1954. Chicago is now close to average for snowfall for the winter, since the city had a snow drought through most of December and January. The ratio of snow to liquid water ranged from 9:1 to 13:1 in the Chicago area, close to the typical 10:1 snow to liquid water snow the Midwest sees.


Figure 1. Satellite image of Winter Storm Saturn/Snowquester at 9:31 am EST March 6, 2013. Image credit: NASA.


Figure 2. Predicted snowfall amounts from Winter Storm Saturn (AKA Snowquester) from the NWS.

Coastal flooding a concern in the Mid-Atlantic and New England
This storm is going to cause a lot of damage to beaches all along the Mid-Atlantic and Northeast coast damaged by Hurricane Sandy in October, and by Winter Storm Nemo on February 9. The powerful onshore winds of the new storm have already piled up a storm surge in excess of 2' along most of the coast from Norfolk, Virginia to New York City. The highest surges at 10 am EST were 4' at Wachapreague, Virginia and 3.5' at Lewes, Delaware. Winds gusting to 55 mph will build waves of up to 15' and a 2 - 4' storm surge along the coast of New Jersey, causing widespread areas of moderate flooding. Moderate flooding is also expected along large portions of the New England coast, from New York City to Boston. The most dangerous flooding is predicted to occur along coast of Cape Cod Bay southeast of Boston, where Friday morning's high tide cycle is expected to be accompanied by a storm surge of 3 - 4' and waves as high as 25', causing major coastal flooding.

We'll have ongoing coverage this week of Winter Storm Saturn in our Winter Storm Section. You can track current storm surge levels using our wundermap with the storm surge layer turned on.

Jeff Masters