Tuesday 9:45 a.m.
A southwesterly flow of warm, moist air ahead of a cold front is contributing to a band of rain and thunderstorms that stretches from the Ohio Valley into parts of the Middle and North Atlantic states. We expect some showers and thunderstorms to cross the I95 corridor from D.C. to Boston later today and this evening.
The cold front should slip south then stall from Virginia or Maryland to Kentucky tomorrow. With the front likely to make only limited progress, some additional showers may occur tomorrow from D.C. to New York City and on west. Most of New England should turn sunny.
In general, computer models suggest a low pressure area forms along the front in the Middle Atlantic states on Friday then slowly moves up along the coast this weekend. If that happens, it will be a damp weekend in the I95 corridor of the Northeast.
In contrast, most of the Great Lakes region looks like it will bask in sunshine with afternoon temperatures in Detroit and Chicago close to 70 and nights cooling to the 40s and 50s. The video has more.
In the longer range, the re-curving of the latest western Pacific typhoon may signal an upper air trough (and cool weather) in the Northeast in a week to 10 days.
Late September is not generally known for widespread thunderstorms, but this map shows near 50,000 lightning strokes in the period from 8 EDT last night until just after 8:30 EDT this morning.
... much greater interest is being generated on threats and rumors about tropical storms. It is worthwhile to read Dan Kottlowski's authoritative reports on this. Here is a copy of his map from this morning:
The tropical Atlantic shows signs of life in the storm development department. Dan Kottlowski's expert discussion suggests the third storm (which could be Hermine) of current concern is one that could head to the Bahamas, Florida, the Gulf or ???
A large high pressure area centered just south of Chicago will furnish a northwesterly of pleasantly cool and dry air to the eastern Great Lakes and all of the Northeast today into Tuesday.
As the trough moves through each locality, warm humid weather will be followed by showers and thunderstorms, then cooler an drier air will arrive
D actually makes up the largest part of this map and represents the large area that is sunny for the most part
The map shows three areas of more concentrated shower activity...