Rain fell across southern and central Chester County this morning as well as in Delaware County where more than 2 inches quickly accumulated causing flash flooding problems; however, Philadelphia, Bucks and Montgomery Counties have been spared from anything significant and it appears that this trend will continue for the next couple of hours. On the New Jersey side of the Delaware River, the rain has had trouble advancing north of a line that extends roughly from Philly to Atlantic City. As the afternoon progresses; however, there will be a tendency for the rain to expand to the north and west into Philly, Montgomery and Bucks Counties and central New Jersey. The heaviest precipitation over the past several hours has occurred over the Chesapeake Bay and Delmarva Peninsula where more than 5 inches has been reported in many places (e.g., Kent Island) and it continues to pour in that area. In the DC region, rainfall amounts have been highly localized with near 4.5 inches of rain reported at Dulles Airport since midnight, but only 1.33 inches at nearby Reagan National Airport.
While the precipitation pattern with this system has been rather localized so far, the cool temperatures are being experienced in all areas. E-NE winds have helped to reduce temperatures throughout the Mid-Atlantic region to below normal levels and that trend will continue into tomorrow. Mid-day temperatures in Philly are in the upper 70’s and the normal for this time of year is about 87 degrees for highs. In DC, the noon reading of 72 degrees at Reagan National Airport is far below today’s normal high temperature of 89 degrees. Much warmer conditions will return to the entire Mid-Atlantic region early next week as the Bermuda high re-establishes itself in the area.