I can honestly say I have never seen this many counties under flash flood watches as one time...this graphic is from around 6:30 tonight. It seems the entire Mid-Atlantic and Northeast is under a flash flood warning at the same time.
Each one of the green diamonds represents a county under a flash flood warning.
A deep southerly flow of moisture continues across the Mid-Atlantic States and northeastern United States on the back side of high pressure over the Atlantic.
This flow is producing copious amounts of rain from northeastern North Carolina and Virginia through Maryland, Delaware, New Jersey and up into New York State, Vermont and New Hampshire. Even western Massachusettes and Connecticut are getting in on the act.
And don't look now, but our much-ballyhooed low pressure system is over northeastern North Carolina, moving northward. It is going to produce widespread 2 to 5 inch rainfall amounts ahead of the center as it moves north through tomorrow.
It did not become a tropical depression or a tropical storm, but winds of 35-40 mph are being reported in the vicinity of the low. At 7 p.m. EDT...Cape Hatteras reported:
RAIN/FOG
Temperature: 77
Dew Point: 74
Humidity: 90% /
Wind: S23G33
Pressure: 29.99S
Add coastal flood problems to the mix and it is a rough night around the Mid Atlantic. A Coastal Flood Warning is now in effect for the tidal Potomac and Chesapeake. Strong onshore winds around the low could push a tidal surge into the Chesapeake and Potoma tonight. Flooding could ensure in places like Alexandria VA and Baltimore's Inner Harbor.
In addition, tornadoes are possible tonight in the strongly sheared environment ahead of the low pressure center.
But the good news is that the end of the rain is in sight. As the low moves northward tomorrow, drier air will finally spread across the region and reach the coast.