Discussion: Over-the-weekend forecast models generally agree on a more impactful storm on the Northeast U.S. versus Friday forecasts. The negative phase of the North Atlantic oscillation (-NAO) previously forecast to weaken implying the storm would be quicker to depart the coastal Northeast and less likely to intensify into a major storm has flat-out reversed. –NAO remains strong through early week. –NAO indicates a blocking high pressure pattern over northeast Canada/Greenland correlating to increased Northeast U.S. storm potential. The –NAO pattern has been intact since late February and the catalyst for the series of Northeast storms. This storm is forecast to be the most intense (968 MB) although further out-to-sea therefore not as windy as the first storm but also more of a snow storm than the rain/snow mix of the previous 2 events.
On Monday morning at 8 AM the storm develops off the coast near Wilmington, NC moving northeast and steadily intensifying to a point east-northeast of Norfolk, VA by 8 PM Monday. Rapid strengthening follows as the storm intensity dips to about the same or slightly stronger intensity than the early March storm. The system is a little farther east sparing southeast Mass. of widespread hurricane force wind however, a gust of 65-70 mph on Cape Cod/Island sis possible given the forecast central pressure.
There’s plenty of cold air at lower (and upper) levels of the atmosphere entrained into the storm track once organized off the Northeast Coast. This storm will be mostly snow including the Mid-Atlantic and New England Coast except a lot of mixing on Cape Cod.
The snowfall forecast is based on the 06Z GFS and indicates one foot of snow for central and northern New England with the 6-inch line across most of southern New England. Amounts could be higher than forecast. Expect another total shutdown of public operations such as schools and some businesses with delays or closings of airports.
The storm is far enough offshore and still strengthening to spare the Mid-Atlantic States of a heavy snow with New Jersey in the 3-6 in. range but amounts drop to the west. Washington and Baltimore are spared.
The upper cold trough causes moderate to heavy snow from the southeast Ohio Valley/Northeast Tennessee Valley across the central Appalachians and into western Virginia plus northwest to central North Carolina. These areas suffer widespread power outages as heavy wet snow will occur at times. The snow line likely reaches the North Carolina/Virginia Coast for this storm.
Wind speeds increase to 15-30 mph Virginia to Delaware coast mid-afternoon Monday to 20-40 mph from Elizabeth City/Norfolk to Atlantic City to Boston very early Tuesday morning and 20-40 mph with gusts to 55-65 mph southeast New England Tuesday morning after daybreak. Max wind for this storm is across east/southeast New England late morning/midday Tuesday with gusts to 50-60 mph expected except 60-70 mph Cape Cod and Islands.
Coastal flooding is a serious problem once again with storm surge not quite reaching 4 feet as observed with the early March storm for north/northeast facing beaches in east/southeast Mass.
Gusty northwest wind follows for WED and THU in the Northeast Corridor and the temperature forecast is revised somewhat colder.