Both the European and American models are predicting a powerful winter storm developing this Friday in the mid-Atlantic region. The American GFS model is predicting that an area along the Maryland Pennsylvania border will get over 30 inches of snow. A corridor from the northern suburbs of the District of Columbia to Baltimore to Philadelphia is forecast to be hammered by twenty to thirty inches of snow driven by strong winds as a deep low bombs off the mid-Atlantic.
The atmospheric wave that will create this intense low over the mid-Atlantic is now part of a storm in the Gulf of Alaska. That jet stream wave will be driven south by the Arctic air mass as it crosses from the west coast to the central states. Then it will whip back up the jet stream towards Virginia, developing a strong surface low pressure area that will pull moisture from the Gulf of Mexico and the Gulf stream up and over the Arctic air mass locked in over the northeastern U.S. When a second jet stream wave kicks in over the Gulf Stream late Friday or early Saturday the storm will “bomb” over the extraordinarily warm waters off the east coast.
Water temperatures as much as 10ºF above normal off the east coast will provide extraordinary amounts of water vapor which will be driven above the Arctic airmass & dump huge amounts of snow.
This situation is an example of what happens when the low level polar vortex breaks down as it did at the end of December and the cold air floods out of the Arctic while temperatures soar near the north pole. The extreme contrast between the near record Gulf Stream warmth and the Arctic air will contribute to the potential for extremely high snowfall amounts. This storm may well be an example of the warm oceans - high snowfall paradox that has so confused cow state senators.
The GFS model predicts a classic mid-Atlantic snow “bomb” to develop off of the Delmarva shores.
Update Mid-day Tuesday:
The new model run shows the very heavy snow amounts centered around Baltimore. The details will continue to change with time but models have been very consistent for days that this will be a powerful storm that sticks around for a long time producing large amounts of snow.
Two feet of snow are forecast for Baltimore from the expected storm this weekend according to the noon Tuesday GFS model run. Models have consistently forecast heavy snow for many days now.
Late Tues afternoon update for Facebook readers: The latest run of the European model bombs the storm over the Gulf Stream off of Cape Hatteras early Saturday morning. Notice the tight small circles (contours) where the deep low is centered over the extraordinarily warm Gulf Stream waters. This European model run forecast is a classic Cape Hatteras bomb. Note also that there’s strong high pressure centered over New England directly north of the storm. This location of entrenched high pressure will slow the storm’s movement leading to increased snowfall amounts.
The European model predicts an intense storm centered over the Gulf Stream off of Cape Hatteras early Saturday morning. High pressure over eastern Canada and northern New England will slow the storm down leading to very high snowfall amounts in the mid-Atlantic if the forecast verifies.
Update Tuesday evening:
The latest American model forecast takes the heaviest snow south of Baltimore into southern Maryland. The European and American models are in very close agreement now. The heaviest snowfall predicted by the latest run of the American model is 37 inches in Charles county Maryland.
The Bullseye, is 37 inches in Charles county Maryland southeast of DC on the latest American model run. The American and European models now agree on the more southerly track that develops the storm of of Cape Hatteras directly over the unseasonably warm Gulf stream.
