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.
Between yesterday morning and early this morning, quite a bit of lightning occurred. There can be some lightning all the way to the East Coast with this cold front, but the activity is likely to diminish. This map shows the distribution of lightning strikes in the (almost) 24-hour period ending at 7:30 ET this morning
The peak of the upcoming warmup should come on Monday for much of the Northeast. This map shows computer projections of temperatures at 4 p.m. ET Monday afternoon. Note the 80+ area in Pennsylvania. Cooler air will arrive by midweek.
As a storm slowly develops along the North Carolina coast, rain that was affecting areas of Michigan, Ohio and western Pennsylvania will tend to redevelop farther east and south. A flow from the east (see map) will keep it cool through tomorrow from New York City to Boston.
A sunny triangle is framed by a band of clouds moving southeast from Wisconsin, rain clouds over the Southeast and the western fringe of a North Atlantic storm.
Jumping ahead almost two weeks, map is the 500mb flow forecast for Mothers Day. If correct, the Middle and North Atlantic states would have a sunny day with afternoon temperatures as high as the 80s! Please remember the models do best in the short range.
This map shows the pressure pattern at 9 a.m. ET. As the high moves closer and the storm moves farther away tomorrow and Wednesday, there should be an increase in sunshine with milder afternoons.