A cold front and high rainfall were moving across the region, meeting warm, humid and unstable air that is uncommon this time of year.

The National Weather Service in Mount Holly, New Jersey, said most of the Lehigh Valley is under a moderate risk for flash flooding, meaning numerous flash floods are likely. Storms are expected to hit the area in the afternoon, and rain could fall at rates exceeding 2 inches per hour.

Storms and flood threats are headed for the New York City area, prompting a string of First Alert Weather Days through the end of the work week. Heavy rain that may cause flooding is expected both Thursday and Friday.