Tuesday 10 a.m.
The rain storm that drenched the I95 corridor yesterday is exiting through northern New England today. A few patches and bands of showers follow the main rain area. As of late morning, one such band (the most prominent) extended from Syracuse, N.Y., to just east of Cumberland, Md.
Meanwhile, showers and thunderstorms are firing up in the central Plains. They are forming near the boundary between a very hot air mass to the south and more moderate air to the north. In response to strengthening trough aloft, a low pressure area will form at ground level along the front and an area of heavy rain with embedded thunderstorms will break out. This activity will affect the southern Great Lakes tomorrow and tomorrow night, then move through the East.
Northeast video from 6:30 a.m. Tuesday:
Chicago area video from 8:30 a.m. CDT Tuesday
This map shows the area that could have damaging thunderstorms tomorrow and tomorrow night.
The NWS Storm Prediction Center issued this outlook for today and tomorrow: A preliminary area of showers may advance from the Carolinas as far as southeastern Pennsylvania and southern New Jersey by tonight.
For the almost 24 hours between 10 a.m. ET Tuesday and 9:20 a.m. ET today, here is a the lightning recap. The dry pattern from the Midwest will now advance across New York and New England.
Cooling aloft and heating moist air closer to the ground should trigger strong thunderstorms from eastern New York and much of New England southwest through parts of the Middle Atlantic states.
The front will move into a region with high humidity as it approaches the I95 corridor tomorrow. This is the basis for SPC's forecast of thunderstorms approaching severe limits tomorrow.
Tropical Storm Colin is caught in the southern stream while the northern stream is helping to send unseasonably cool air out of central Canada.
Then, as the cold front arrives, there may be violent thunderstorms. This map shows the early morning SPC assessment of the severe weather risk on Sunday: