As a cold front approaches New Jersey, a line of potentially strong thunderstorms will become likely starting Sunday late afternoon.

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NAM model forecast shows strong thunderstorms over New Jersey starting around Sunday 4 p.m. (College of DuPage Meteorology)


Sunday morning is starting off with mostly to partly sunny skies, high humidity, and temperatures reaching for the upper 80s by the afternoon. Clouds will increase steadily starting late morning, eventually leading to a quick burst of thunderstorms later on. Given the heat and humidity in the atmosphere on Sunday, and the sharpness of the approaching cold front, those storms are likely to be strong to severe for at least part of the Garden State.


HRRR model forecast showing strong thunderstorms over New Jersey around 6 p.m. Sunday. (College of DuPage Meteorology)

Isolated showers have already popped up Sunday morning around Bergen County. The main event will begin with spotty showers and light thunderstorms in western New Jersey, as early as about Noon. The real concern will come between 4 p.m. and 10 p.m. as the strongest thunderstorms sweep through the state. That's admittedly a pretty big range of time - forecast models differ slightly regarding the exact timing of the strongest storms, ranging from late afternoon to late evening Sunday. I think it's safe to say you'll want to watch the skies closely if you're out and about Sunday afternoon or evening, and be prepared to head indoors if they darken up and/or you hear thunder roar.


The Storm Prediction Center outlook for Sunday puts the western half of New Jersey in a marginal risk for severe weather. (NOAA / NWS / SPC)

The strongest storms are most likely in the western half of New Jersey. It's mostly a matter of timing - once the sun sets, the storms will lose a lot of their energy, and will be prone to pulse down in intensity. Strong to severe thunderstorms are certainly still possible in NE NJ and along the Jersey Shore, but the odds are a bit lower. The Storm Prediction Center concurs, placing western New Jersey in a "Marginal Risk" for Sunday. That's the lowest of their 5 severe weather risk categories.


So if the severe risk is only marginal, why am I taking time of the weekend to warn you of the impending danger? Because I don't want it to be a surprise. The weekend has been mostly gorgeous so far, with 95% of the state enjoying sunshine and warm temperatures. It's a very popular vacation weekend, so beaches, parks, and backyards are packed with New Jerseyans and out-of-towners alike. The line of storms may arrive very quickly, and so it's important not to be caught off-guard.

Typical of a line of summer thunderstorms, the biggest concerns will be rain and wind. A brief period of heavy rain (about an inch within an hour) may rapidly lead to flooding of low-lying areas and temporary inundation of streets and streams. Remember to never attempt to drive, walk, or swim through flooded areas: it is incredibly dangerous, and pretty disgusting.

The threat for damaging winds will be limited to the strongest storms Sunday afternoon and evening. Gusts over 60 mph may cause downed trees and power lines, and may cause other damage as well. In case warnings are issued, you should be prepared to take shelter in a sturdy building until the storms pass.

Beyond the Storms

Any lingering storms or showers will end overnight Sunday, especially after midnight. The resulting air mass will be ridiculously dry, as dew points plummet from around 70 (steamy) to around 50 (comfy) on Monday. With a strong area of high pressure in control and humidity remaining very low, New Jersey will be treated to a gorgeous week of weather. For the most part, skies will be crystal clear and daily high temperatures will be pleasantly warm in the 80s. Our next chance of rain will hold off until Thursday or Friday, at the earliest.

Dan Zarrow is Chief Meteorologist for Townsquare Media New Jersey. Follow him on Facebook or Twitter for the latest forecast and realtime weather updates.