The National Weather Service has issued a flash flood watch for 19 of New Jersey’s 21 counties, saying rain showers and thunderstorms on Friday and Saturday could drop as much as 3 to 5 inches of rain on areas that are already saturated because of heavy rain from Tropical Storm Henri and other recent storms.
The weather service says slow-moving storms from the west could tap into heavy moisture in the atmosphere and produce quick but heavy downpours that could cause streets to quickly flood.
“With recent heavy rainfall, it won’t take much additional rain to result in flash flooding,” the National Weather Service’s New York regional office said in its flash flood watch, which covers Bergen, Essex, Hudson, Passaic and Union counties in northeastern New Jersey.
Flash flood watches were also issued Thursday afternoon in every other county across the state, except for Sussex and Cape May.
The weather service’s Mount Holly office said a slow-moving frontal boundary will “likely trigger multiple rounds of thunderstorms from Friday afternoon through much of Saturday.”
“Storms are likely to be slow moving and produce torrential rain,” the office added. “A general 1 to 3 inches of rain is forecast, but locally higher totals over 5 inches are possible. Combined with wet antecedent conditions, this could lead to flash flooding.”
The flash flood watch, which is not as urgent as a warning, goes into effect at 2 p.m. Friday and continues until 2 a.m. Sunday.
New Jersey was hit hard by multiple waves of heavy rain caused by Tropical Storm Henri and a low-pressure system that pulled moisture from the storm from Saturday through Monday, with some areas of the state getting pounded by as much as 6 to 9 inches of rain.
Dry weather finally took hold on Tuesday and Wednesday, but some isolated rain showers and thunderstorms have been moving across parts of the Garden State Thursday afternoon.
Current weather radar
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Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com.