Thursday 10 a.m.
While many places from Pennsylvania to Massachusetts had dry weather this morning, showers and thunderstorms have been drenching, and in some cases flooding, the area from central and eastern Virginia into southern Maryland and southern Delaware. This is a picture from the Dover, Del., radar at 10 a.m. EDT:
This video show how things should progress during the next several days.
Tomorrow will be a warm, humid midsummer-style day for the Middle Atlantic and southern New England states. However, a strong cold front will advance through the Great Lakes late tomorrow through Saturday then move off the East Coast Sunday. Cooler, drier air will follow the front. However, downwind from the Great Lakes, the action of cool air passing over warm water will cause lake-effect clouds and perhaps showers.
A cool high pressure area should be in charge of Northeast weather Monday and Tuesday, then southwest winds will roll back the coolness, and it should be warmer Wednesday and Thursday.
Tropical storm season is quite busy right now. Hurricane Michael blew up into a Category 3 storm over the central Atlantic, Leslie churns slowly toward the general area of Bermuda and the piece of Isaac that meandered south to the Gulf is in a place where storms can strengthen.
Along I95, rain ruled through midmorning while marshmallows of wet snow changed the gray November landscape to winter white very fast inland. I told Sam The Dog about the snow before it started in the middle of Pennsylvania. He was taking a wait-and-see attitude.
The profile here is for New York City at 1 p.m. tomorrow. We see it is forecast to be just above freezing near the ground. Will big wet flakes make to the ground or will they melt into rain drops? Or will there be a mix? It's a very close call call.
This pressure map shows the strong circulation around the storm that brought all the warm air northward... and which will force colder air eastward next.
Looking at next week, the GFS ensemble spaghetti plot of upper air winds shows how much agreement there is among members of the ensemble (same model running multiple times using slightly different starting assumptions). The maps are from next Tuesday, Nov. 25, and Thanksgiving Day, Nov. 27. There is good agreement on the first map, but a lot of spread two days later.
The location of lake-effect snow bands is tightly controlled by geography, topography and wind. From this pressure analysis, we see why the wind favored heavy snow staying south of the hardest hit Buffalo snow belts earlier today.
If this timing works out, there would be good travel weather for the Northeast Corridor on Wednesday while snow showers cross the Great Lakes and reach the northern and central Appalachians.