Severe thunderstorm watch, flash flood watch in effect until Tuesday night

A severe thunderstorm watch has been issued in Upstate New York for the second day in a row. Hail, frequent lightning, and heavy rain are also possible.

This model is depicting the heaviest rain and greatest potential for severe weather to the west of Boston.

Strong thunderstorms have been moving across eastern Pennsylvania and into northern New Jersey during the past hour, prompting the National Weather Service to issue a severe thunderstorm warning in several counties in the region.

There is a risk of flash flooding, severe thunderstorms, and even tornadoes from 2 p.m. Monday afternoon to 6 a.m. Tuesday, forecasters wrote in a statement.

A watch means conditions are favorable for damaging thunderstorms in and around the watch area. The so-called “precipitable water” – an integrated value of how much water can theoretically rain out in any one location – is very high.

Multiple rounds of thunderstorms could spark flash flooding. The stronger storms will be capable of producing damaging wind gusts and hail. Rainfall amounts of 1 to 2 inches are possible with localized totals of 3 to 5 inches possible.

A heavy thunderstorm pelted central NY with golf ball-sized hail last month, with thousands losing power from the sudden high winds.

Additionally, the Weather Service has placed a large segment of our region under a flash flood watch until 9 p.m.

Ocean waders and swimmers should pay attention to flags and posted signs, and only swim near a lifeguard, the weather agency said.

The rain showers will clear out late in the evening and the weather should be quiet overnight. Warm and very humid air is in place over the area.