This video shows how a cold front coming into the East will trigger thunderstorms and perhaps interact with a tropical system that is now east of Florida.
The thunderstorms that raked across the Chicago area last evening knocked out power for hundreds od thousands of people, damaged building and toppled trees. The storms weakened rapidly after crossing Michigan and Indiana. This map shows the lightning strokes from 11 a.m. ET yesterday through 10:25 a.m. ET today:
(2) is an area of showers and thunderstorms with no defined circulation. This disturbance may follow the same general path as (1).
If correct, cooler, drier and more comfortable weather will take over in the Northeast as we go into the holiday weekend, then warmth and humidity would increase as we go through next week. This map matches that scenario.
that short wave is what the models latch onto in bringing a cold front through the Northeast Wednesday night and Thursday. This would bring noticeable cooling to the Northeast late in the week.
Labor Day is a week from Monday. The computer model used here, the GFS ensemble mean, suggests the weather will favor outdoor late summer activities across the Great Lakes and Northeast:
In response to heating at ground level and a weak cold front approaching from the west, showers and locally strong thunderstorms should develop across northern Ohio this afternoon.
... 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: