Our most recent storm is in “a state of flux” early today, but it is still causing pockets of heavy rainfall across parts of the Northeast and in the mid-Atlantic states.
As of 4:40 a.m. the regional radar mosaic was showing that the heaviest and most widespread rain was occurring in areas north and west of I-95, while much of South Jersey (located in a “warm sector”) wasn’t seeing much rain at all. This will most certainly change as the morning unfolds, because the low pressure system that will move across the region early today is going to be dragging a cold front across the coastal plain during the next several hours. With this in mind, the corridor of heavy rain which was occurring prior to 5 a.m. across most of eastern Maryland, southeastern Pennsylvania and as far south as central Virginia will be marching eastward, and it will inundate the big cities and the entire coastal plain between NOW and 8 a.m. – - causing rainfall at rates of up to 1 or even 1.5 inches per hour before tapering to a few showers and then ending by midday (or before noon). This will most definitely lead to flooding in areas of poor drainage, as well as flooding of some streets and highways, some rivers and small streams.
And, on this extremely busy travel day prior to Thanksgiving, there will also be significant weather-related delays at the airports.
We must also remember that after flights get “back-logged” this morning, this will tend to have a ripple effect throughout the day– so, even if someone has a flight for this afternoon or early tonight, when the bulk of this rain will be over, there still may be some residual delays. Temperatures will probably manage to climb into the mid-60s across the greater Baltimore area before the cold front comes sweeping through during midday. Therefore, we should talk about temperatures probably peaking in the lower 60s this morning before they begin to fall steadily later behind our cold front. By the evening rush, for example, most temperatures will probably be in the lower or mid 50s. With gradual clearing expected tonight, temperatures will be rolling back into the 30s in most places, with north winds averaging 10-18 mph overnight. Those winds tomorrow should be mostly out of the west, averaging 7-14 mph. And with sun returning, we expect most temperatures to be in the 50s on Thanksgiving Day.