Philadelphia, Pa. – An increasingly active weather pattern will bring rounds of thunderstorms to eastern Pennsylvania, New Jersey, Delaware and adjacent Maryland beginning Monday afternoon, with the greatest concern shifting to flash flooding and stronger storms on Tuesday. Heavy downpours could quickly overwhelm urban streets, poor drainage areas, creeks and small streams, creating hazardous travel conditions.
According to the National Weather Service in Mount Holly, scattered thunderstorms will develop Monday afternoon and evening across New Jersey, eastern Pennsylvania and the Delmarva Peninsula. The region is under a Level 1 of 5 Marginal Risk for severe weather, where a few storms could produce locally damaging wind gusts and heavy rainfall.
The threat increases on Tuesday as thunderstorms become more widespread. The Storm Prediction Center places areas south of Philadelphia, including portions of southern New Jersey, Delaware and Maryland’s Eastern Shore, under a Level 2 of 5 Slight Risk for severe thunderstorms. Damaging winds and torrential rainfall are expected to be the primary hazards.
The Weather Prediction Center also highlights much of eastern Pennsylvania, New Jersey and Delaware for a Level 2 of 4 Slight Risk of excessive rainfall Tuesday. Rainfall rates of 2 inches per hour or greater are possible, raising the likelihood of flash flooding in cities, low-lying roads, poor drainage areas, creeks and small streams. While widespread river flooding is not currently forecast, repeated heavy rainfall could cause significant rises on nearby waterways.
Communities including Philadelphia, Wilmington, Trenton, Dover, Atlantic City, Reading and Allentown should closely monitor weather updates through Tuesday. If a Flash Flood Warning is issued, avoid driving across flooded roads and seek higher ground if flooding develops. Residents should also have multiple ways to receive watches and warnings as thunderstorms may strengthen quickly.
Additional watches or warnings may be issued Monday and Tuesday as confidence increases in the timing and location of the heaviest rainfall and strongest storms.
