There is now consensus among computer models that a strong fall Nor’easter will begin forming election night and then move up the Mid-Atlantic and Northeast coast Wednesday and Thursday.
How close to the coast the storm tracks remains the looming question. That will dictate how far west (inland) precipitation and strong winds reach.
But from the North Carolina Outer Banks to the shores of New England, it’s becoming more certain that the storm will whip up high seas and gusty winds, leading to a new round of coastal flooding and beach erosion on the heels of Superstorm Sandy - though not as severe.
All four of the “big 4” global computer models - the European (EURO), the UKMet, the Canadian and U.S. GFS - indicate a fairly powerful area of low pressure will rapidly develop along the Southeast or Mid-Atlantic coast late Tuesday into Wednesday. This will occur as two disturbances - one from Canada, the other from the southern U.S. - join together or phase.
As this storm is getting its act together, high pressure will be parked to its north. The unfortunate juxtaposition of strong high pressure to the north and deepening low pressure to the south will funnel winds off the ocean onto the land for the same region that took a beating from Sandy. Sustained winds over 35 mph (gusting to over 45 mph), large waves, and high seas are likely.
The National Weather Service in Mt. Holly cautions for coastal areas from the northern Delmarva into southern New Jersey: THERE IS A DECENT CHANCE OF GALES AND THE POSSIBILITY OF STORM CONDITIONS BY LATE WEDNESDAY.
The NWS in NYC adds: COASTAL FLOODING AND BEACH EROSION IS A CONCERN. . . .
STRONG...GUSTY WINDS ARE BECOMING MORE LIKELY. SUSTAINED SPEEDS RANGING BETWEEN 20-35 MPH WITH GUSTS BETWEEN 45 TO 60 MPH IS A DEFINITE POSSIBILITY.
. . .
SEVERE BEACH EROSION RESULTED FROM SANDY AND THIS STORM COULD VERY WELL EXACERBATE THE SITUATION AT THE IMMEDIATE COAST.
The models differ in how close to the coast the storm forms. The EURO and UKMet models develop the storm close enough for moderate to heavy precipitation to reach Washington, D.C. and Baltimore and much of the Northeast I-95 corridor. The GFS model develops the low a bit further offshore, with more of a glancing blow for the Mid-Atlantic (with most rain in coastal areas) but stronger effects up the coast. The Canadian model is something in between the EURO/UKMet model solution and the GFS.
D.C. area impacts
“The question is whether it’s going to barely miss the D.C. area or give us a good slug of precipitation”, said Wes Junker, Capital Weather Gang’s winter weathere xpert.
For the interior Mid-Atlantic and Northeast, the European model continues to hint at the possibility of some snow especially west of the big cities and up in elevation.
“There are still indications - even though a long shot - that some of precipitation may fall as snow,” Junker said.
“[For the D.C., Baltimore area] we won’t know for sure for another 24-48 hour if snow will fall,” Junker continued. “Much of it will depend on how hard it precipitates and the storm track - both of which will affect how much cold air will work its way down to the ground.”
If snow were to fall in the D.C. area, it would likely occur Wednesday night and would probably have trouble sticking except perhaps in elevated areas well west of the city (if the precipitation extends that far inland).