A band of heavy rain and locally violent thunderstorms moved from the New York City area at 4 a.m. to just past Boston (distance: 188 miles) by 9:30 this morning. Note the stunning contrast between where it is pouring (dark red) and where it has dried out.
On the map, showers and thunderstorms were located along and ahead of the gray line that cuts through Pennsylvania and along/ahead of the blue line. Both should be off the East coast by Thursday. Drier air from the Upper Midwest should filter into the Northeast later in the week.
The large storm that drenched the Northeast during the weekend has drifted out to sea and somewhat drier air is coming in to replace it. However, another upper air trough extending from Wisconsin to Louisiana is supporting several pockets of showers and thunderstorms.
From northern West Virginia across most of Pennsylvania and western and central New York, there could be several inches of rain with flooded streets and streams.
...will move east to bring rain overnight from parts of Virginia to Southern New England. In the southern part of this area there can be some violent thunderstorms late today and tonight. The rain will depart tomorrow, but a large storm is likely to affect the Middle and North Atlantic states this weekend.
This activity map produced by the National Weather Service Storm Prediction Center overlays existing areas of thunderstorms on the map showing various risk levels.
The radar image below showed a line of showers and thunderstorms extending from the Hudson Valley of New York to the middle of Pennsylvania. The heaviest rain shows up in red. These storms were near Lake Erie four to five hours earlier and will head toward and then past the I-95 corridor this afternoon and tonight.
A low pressure area and cold front will set off thunderstorms that can produce damaging winds, heavy rain, hail and even some tornadoes. This map shows where the greatest risk of violent thunderstorms will exist later today into tonight.
Bill will drift eastward toward the Middle Atlantic coast by late Sunday. At the same time, a cold front from the northern Plains. It can cause strong thunderstorms from Wisconsin across Lake Michigan tomorrow night, then farther east on Sunday.
You've probably seen videos that show people and their vehicles surrounded by water, sometimes needing daring rescues. It is tempting to ask yourself how people got themselves into those situations. They thought they could make it!