A late winter coastal storm is likely to affect the DC-BOS Corridor from very early Tuesday into Wednesday. Biggest threat is heavy snow as it should move fast enough to limit storm surge and erosion effects on east-facing beaches.
At this time (9 am Sat), the low is forecast to strengthen rapidly near HAT early Tuesday morning with the center passing over Cape Cod near midnight on Tuesday night. The medium range forecast models are in good agreement on the track of the storm. The short range models are just now seeing the storm in their forecast window (0-84 hours) and, as usual in this situation, are a bit more scattered.
The storm will be driven by two disturbances in the upper atmosphere dropping southeast from western Canada. The “phasing” of these two disturbances (think of it as resonance between two waves) will drive the development of a strong surface low near HAT late Tuesday morning.
The rain/snow line forecast for this storm is east of the I-95 Corridor at this time. Locations on the Eastern Shore of MD, and the Outer end of Cape Cod are currently on the rain side, with all the major cities on the snow side. I would put any confidence in this line at this time but it’s worth noting that all the models have a very sharp changeover from rain to snow.
Snow likely to start in VA Monday night, heavy in the DC-PHL Corridor overnight and into rush hour on Tuesday. New England will get the snow beginning Tuesday afternoon. Lots of snow but too soon to get into specific amounts.
If the center of the low does track over Cape Cod as forecast, then the extent of strong easterly winds, fetch and erosion will be limited. The strongest easterly winds along the MD/NJ coast will be midday to early afternoon Tuesday and in Cape Cod Tuesday afternoon. Strong NW winds in the wake of the storm Wednesday.
“Whatever truth drops on, it eventually grinds it to a
powder.” Art Blakey