Seasonal Transition

Discussion: We have a few players shaping our conditions this week. At the upper-levels we have a ridge (still over E US) moving away to the E. This ridge should influence NJ with some warmer temps and humidity through about Wednesday. We’ll then have a trough move in for Thursday which should begin a prolonged series of lower geopotential heights as far as I can see out. The trough arrival Thursday should place NJ under a strong southerly upper-level jet which could enhance Thursday rain and thunderstorm chances. At the surface, we have high pressure sliding away to the E (in correlation with the departing ridge). Today is another amazing day (like yesterday) but humidity should trickle back in for Tuesday-Wednesday. Wednesday into Thursday looks the most unsettled surrounding a cold front passage (again, enhanced by the upper-level S jet). I would expect periods of heavy rainfall and embedded thunderstorms capable of reaching severe criteria). The rain/storms should then end with the frontal passage by Thursday night/early Friday AM and leave an amazing weekend in its wake…southern California weather Friday through at least Sunday. With all of this said, I think we can kiss summery weather goodbye for a while, starting this Friday, just two days after the actual start of fall. So basically, this week we transition from summer to fall. The tropics remain active S of the 30N latitude but nothing is threatening NJ either currently or on the near-horizon.  

Monday (Sept 20) high temperatures should reach the mid-to-upper 70s. Skies should be mostly sunny with a pleasant feel. Winds should be light out of the W/SE. Overnight lows should range from mid-50s to near-70 from NNJ elevations to SNJ coasts.

Tuesday (Sept 21) high temperatures should reach the mid-to-upper 70s again. Skies should be mixed with sun and clouds with returning humidity. Winds should remain light out of the E/SE. Overnight lows should range from mid-60s to lower-70s from NNJ elevations to SNJ coasts.

Wednesday (Sept 22) high temperatures should reach near-80 for most areas. Skies should be mostly cloudy with a few sunny breaks. Passing showers are possible, especially after noon. A humid feel should continue otherwise. Winds should be light-to-breezy out of the S/SE. Overnight lows should fall into the upper-60s for most areas with rain chances persisting into Thursday morning.

Thursday (Sept 23) high temperatures should reach near-80 for most areas. Skies should be mostly cloudy and humid with rain and thunderstorms likely. Winds should be light out of the S/SE. Overnight lows should fall into the 60s statewide with maybe a few 50s for NNJ elevations and interior SNJ Pine Barrens.

Friday (Sept 24) high temperatures should max out in the lower-70s for most areas. There might be some rain leftover during extreme early AM hours but conditions should rapidly improve behind the cold front. Winds should be light out of the W/NW. Overnight lows should range from near-50 to near-60 from NNJ elevations to SNJ coasts.

An early look at the weekend indicates stellar conditions. Highs in the low-to-mid 70s, lows in the mid-to-upper 50s, and clear skies. Let’s make sure it still looks this way in a few days. Everyone have a great week and please be safe! JC

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Jonathan Carr

Jonathan Carr (JC) is the founder and sole operator of Weather NJ, New Jersey’s largest independent weather reporting agency. Since 2010, Jonathan has provided weather safety and forecasting services for New Jersey and immediate surrounding areas through the web, social media, and app spaces. Originally branded as Severe NJ Weather (before 2014), Weather NJ is proud to bring you accurate and responsible discussions ahead of high-stakes weather scenarios that impact the garden state. All Weather. All New Jersey.™