N.J. weather: Severe thunderstorm watch issued for all 21 counties as strong storms, flood threats loom

Update: The severe thunderstorm watch for all 21 counties expired at 9 p.m. Tuesday.

With heavy rain in the forecast and wind gusts of up to 70 mph possible, the National Weather Service has issued a severe thunderstorm watch for all 21 counties in New Jersey.

The watch took effect at 1:45 p.m. and runs through 9 p.m. Tuesday. It also covers the New York City and Philadelphia metro regions.

Heavy rain and strong thunderstorms are expected to fire up in the Garden State late this afternoon and might last though the evening as a slow-moving cold front pushes its way toward our region.

In addition to gusty winds that could be strong enough to knock down trees and power lines, forecasters also say flash flooding and hail are possible.

The weather service said Tuesday’s showers and thunderstorms could generate rainfall rates as high as 2 inches per hour.

“If storms train over any one area for a period of time, this could result in localized rainfall totals of 3 to 4 inches,” the agency’s forecast office in Mount Holly said.

A small thunderstorm cell was moving across northern Sussex County at about 1:25 p.m., prompting the weather service to issue a severe thunderstorm warning for that area of the state. The warning is in effect until 2:15 p.m.

Another thunderstorm warning is active for western sections of Passaic County through 2:45 p.m. Tuesday.

This is the second straight day with forecasters warning of potential flash flooding, but widespread flooding did not materialize on Monday because those storms turned out to be weaker than anticipated.

When a severe thunderstorm watch is issued, people should be aware of the possibility of strong storms on the way. A warning is more urgent than a watch.National Weather Service

A severe thunderstorm watch is not as urgent as a warning. It simply means conditions in the atmosphere are favorable for strong thunderstorms with intense winds, frequent lightning and heavy downpours.

All of New Jersey remains under a flood watch, starting at 2 p.m. and continuing through midnight. In addition, most of the state is under a heat advisory because of air temperatures rising into the upper 80s to low 90s and high humidity making it feel as hot as 100 to 105 degrees.