Forecast Overview
New Jersey is bracing for several days of unsettled and potentially dangerous weather, with the National Weather Service forecasting multiple rounds of severe thunderstorms and flash flooding from Tuesday through Thursday.
According to the National Weather Service, isolated showers and thunderstorms are possible on Monday evening, though the risk of hazardous weather remains low. Monday's highs are expected to reach the upper 70s to mid-80s under mostly cloudy skies, with overnight lows in the mid-60s to low 70s. Patchy fog is possible late Monday night into early Tuesday morning, especially across northern and central New Jersey.
Tuesday: The Storm Threat Begins
Tuesday will mark the start of a more active weather pattern. The Storm Prediction Center has placed most of the state under a slight risk (level 2 of 5) for severe thunderstorms. The National Weather Service noted early Monday that while "exact details regarding timing and coverage of storms remain uncertain, there is potential for any thunderstorms to produce damaging winds and large hail," adding that "a tornado or two cannot be ruled out."
Afternoon highs are forecast to climb into the mid-80s to low 90s, about five degrees above average for early September. Heat indexes could reach into the 90s to around 100 degrees in some areas, prompting forecasters to monitor conditions for potential heat advisories. The highest chance of severe storms Tuesday is expected across western New Jersey during the afternoon and evening hours, where damaging winds, large hail, and a brief tornado are all possible.
Wednesday and Thursday: Continued Risks
Wednesday's forecast is similar, with nearly all of New Jersey under a slight risk for severe thunderstorms. The National Weather Service warned of "areas of heavy showers and thunderstorms" on both Tuesday and Wednesday, with "localized areas of excessive rainfall possible." Rainfall rates of one to two inches per hour are possible, and storms on Wednesday could cluster over the same areas, producing totals of more than three inches and triggering flash flooding.
However, forecasters noted that Wednesday's thunderstorm threat has trended lower, as a frontal boundary draped across the region may bring easterly winds and a marine influence that could limit storm development. The threat is expected to ramp back up on Thursday as that same frontal boundary moves back through the area, again bringing the potential for severe thunderstorms with damaging winds, large hail, and tornadoes during the afternoon and evening.
Flash flooding remains a concern throughout the Tuesday through Thursday period, given the potential for multiple rounds of heavy rain falling on already-saturated ground from recent rainfall. The National Weather Service said there is still considerable uncertainty regarding the exact placement and timing of the frontal boundary and associated storms, particularly for Wednesday and Thursday.
Regional Details
For Monmouth and Ocean counties, the National Weather Service forecasts three days of rain and storms, with severe thunderstorms and flooding possible. High winds, hail, heavy rain, and even tornadoes are all possible from Tuesday through Thursday, although no watches or alerts had been issued as of the latest reports. Rain is forecast to start after 2 m. Tuesday. Temperatures in the two counties are expected to reach the upper 80s on Tuesday, the upper 70s on Wednesday, and lower 90s on Thursday, with cooler conditions along the coast.
Ray Kruzdlo, a hydrologist at the National Weather Service in Mount Holly, explained that watches for severe thunderstorms and flash flooding are typically issued six to twelve hours ahead of an event, while warnings are issued about an hour before.
Labor Day Weekend Outlook
The unsettled pattern is expected to break down by Friday as high pressure builds in from the north, bringing an end to the severe weather and flash flooding threat. The National Weather Service said the Labor Day weekend is "shaping up to feature nice weather, with temperatures trending slightly below normal and lower humidity."