Several severe weather alerts are in effect in Lancaster County, according to the National Weather Service.
"Any storm that survives over Long Island should produce very heavy rain, risky lightning and strong winds", Hammer said. The flash flood watch will be in effect through 4 a.m. Tuesday.
Excessive runoff from heavy rainfall could cause flooding on highways, streets, underpasses, and other drainage areas and low lying spots.
The entirety of Central and Western Massachusetts is under a severe weather watch that included potential tornadoes, the National Weather Service said Monday. The National Weather Service in Binghamton has issued a * Flash Flood Watch for a portion of central NY, including the following areas, Onondaga, Schuyler, Seneca, Southern Cayuga, Steuben, Tompkins, and Yates.
The storm risk starts around 12 p.m. Monday. Localized amounts of up to 5 inches are possible, too.
The seacoast will be the last to see the storms. In addition to always risky lightning these storms will bring very strong straight-line winds (and perhaps a tornado somewhere) along with very heavy rains. The threat will continue into the early evening. Morning lows will be down into the 50s with daytime highs in the low to mid 80s.
The most active hour with pockets of heavy rain for the Baltimore area is around 3:30 p.m.