Flash Flood Warning Issued In 9 NJ Counties Thursday

5:37 p.m. update: A flash flood warning is in effect in Middlesex, Monmouth, Morris, Somerset, Hunterdon and Burlington counties until 7:30 p.m. A flash flood warning is in effect for Essex, Passaic and Union counties until 10 p.m. Winds up to 60 mph were observed near Somerville around 3:34 p.m. on Thursday capable of damage to roofs, siding, trees, and power lines, according to the National Weather Service.

NEW JERSEY - The Garden State is expected to see severe thunderstorms hit the region later today, bringing with it flash flooding, strong wind gusts and up to three inches of rain in parts of the state, forecasters said Thursday. Isolated tornadoes are also possible.

The National Weather Service said heavy rainfall is expected to start in the afternoon and may lead to flash flooding, with an “elevated” risk of flash flooding on and northwest of the I-95 corridor. The agency has already issued a flash flood watch for Sussex, Morris, Somerset, Warren, Hunterdon, Mercer, Essex, Bergen, Hudson, Passaic, Middlesex and Union counties through Friday morning.

Here is the large and occluded upper-level low over the Ohio Valley responsible for today's severe and flash flooding threat. Notice the strong southerly winds ahead of the system bringing ample moisture into our region. #PAwx #NJwx #MDwx #DEwx pic.twitter.com/MuRprPKvMQ
— NWS Mount Holly (@NWS_MountHolly) September 23, 2021

A coastal flood advisory is in effect for Salem County until 3 p.m. on Thursday. A similar advisory has been issued for Gloucester, Camden and Burlington counties between 2 and 7 p.m. Thursday.

“Up to one half foot of inundation above ground level expected in low-lying areas near shorelines and tidal waterways,” the National Weather Service said. “At this level, flooding begins on the most vulnerable roads in bayside communities and along tidal waterways. Some partial or full road closures are possible.”

A coastal flood advisory means that minor tidal flooding is expected. Minor tidal flooding often results in some road closures with the most vulnerable roadways likely to flood.

“Do not leave your vehicle at a location that is prone to tidal flooding,” the agency said. “Do not drive your vehicle through flood waters. The water may be deeper than you think it is. You will be putting yourself in danger and your vehicle may be damaged, leading to costly repairs.”

Some impacted areas at the northern border of New Jersey and Pennsylvania - as well as parts of the Jersey Shore - could see up to three inches of rain. Other areas south of the I-95 corridor are set to see around an inch to an inch and a half of total rainfall. Locally higher amounts up to five inches are possible.

Flash flooding is also possible in streams, creeks and urban areas, as well as areas with poor drainage.

Strong wind gusts are an additional area of concern in the state today, as damaging straight-line winds and isolated tornadoes are possible, according to the National Weather Service. The main threat will occur between midday Thursday into overnight Friday.

“Strong to severe storms may develop,” the agency said. “Storms will be capable of producing damaging wind gusts and isolated tornadoes, potentially bringing down trees and power lines.”

Rainfall is expected to end before 8 a.m. on Friday with temperatures around the 70-degree mark.

A high rip current risk remains in effect for the Jersey Shore through Friday evening.

“Entering the surf is discouraged. If caught in a rip current, relax and float,” the National Weather Service said. “Do not swim against the current. If possible, swim in a direction following the shoreline. If unable to escape, face the shore and call or wave for help.”

Here is the latest forecast:

Thursday: A chance of showers and thunderstorms, then showers and possibly a thunderstorm after 1 p.m. Some of the storms could produce gusty winds and heavy rain. High near 81. Southeast wind around 15 mph, with gusts as high as 30 mph.

Thursday Night: Showers and possibly a thunderstorm before 11 p.m., then showers likely. Some of the storms could produce gusty winds and heavy rain. Low around 58. West wind 5 to 10 mph. Chance of precipitation is 90 percent.

Friday: A chance of showers, mainly before 8 a.m. Partly sunny, then gradually becoming sunny, with a high near 72. Northwest wind around 5 mph.

Friday Night: Clear, with a low around 52. West wind around 5 mph becoming calm in the evening.

Saturday: Sunny, with a high near 74. Calm wind becoming northwest around 5 mph.

Saturday Night: Mostly clear, with a low around 54.