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.
However, rainfall is increasing south of New England, and southerly flow aloft should bring rain to Providence, Boston and other parts of New England.
Early this morning, the most concentrated rain was falling in a band from Maryland to southern Michigan.
With a high pressure area over Maine, a low pressure area over western Indiana and an upper-air storm spinning over the western Great Lakes, the stage is set for wet weather in the Middle and North Atlantic states.
This map is a rainfall forecast from the NWS Middle Atlantic River Forecast Center located in State College, PA.
The upper-air flow forecast for this evening shows the trough that helps to support rainfall ahead of the cold front.
After reaching the 80s today from NYC to Boston, it might not be that warm again through much of next week.