Warm/Wet Start into a Cold Weekend

Discussion: A low is currently tracking to the N of the Great Lakes. We’re between the warm front and the decaying cold front attached to that low, otherwise known as a warm sector in the Norwegian Cyclone Model Theory. This synoptic force feeding into the low is what’s pulling the very mild air into NJ today from the S/SW. Expect this to continue into Wednesday as a few rounds of rain move through (this morning’s rain has ended, rain tonight into tomorrow morning, then again Wednesday night into early Thursday. Thursday will be a day of transition as a colder air mass reloads over NJ. We should then step down into an even colder airmass Friday into the weekend…the coldest air of the fall to end calendar fall. I’m seeing daytime highs in the 20s/30s and overnight lows in the single-digits/teens Sunday into Christmas Eve. I am still watching the weekend for some potential snow but models have backed off the idea of a larger storm system. We’re going to have two pieces of energy (one near the lakes and another off the SE US). How much they interact will determine if any snow showers will occur. It will definitely be cold enough for snow to fall and stick, especially overnight. So even just a coating to an inch or two from widespread snow showers could give some a white Christmas. Right now the models are showing just enough for flurries basically but I’ll be watching for any level of increased interaction between the two. For a larger snow system, we’re likely going to have to punt into the new year. A warmup is now detected between Christmas Day and New Year’s Day. But there are signs of cold fiercely reloading to start 2025…as it typically does in January. I wish I had better news for the snow lovers, but here’s to hoping for trace-coating this weekend.

In English: Warm and rainy through Thursday morning (small breaks between). Thursday a day of transition. Cold Friday through Christmas Eve. No larger snowstorms expected (dropped off of model guidance) but widespread snow showers this weekend are not off the table yet. Warmup Christmas Day-New Years then cold reloads to start 2025.  

Forecast

Monday (Dec 16) high temperatures should hang in the upper-30s/lower-40s for NNJ elevations, especially with any fresh snowpack. The rest of NJ is sitting in the 45-55 range with the warmest temperatures occurring in SENJ. A short mid-day lull in rainfall is expected before more rain moves in by evening/for overnight into Tuesday. Winds should stay lighter out of the E/SE away from the ocean but breezier, possibly gusty overnight out of the S for ECNJ/SENJ/SNJ coasties. Overnight lows should range from 35-50 from NNJ elevations to SNJ coasts. Temps could actually rise through the night for the warmer NJ locations.

Tuesday (Dec 17) high temperatures should start and stay mild with a general range of 55-60. Rain should end by mid-to-late morning with conditions improving throughout the rest of the day. It will remain mild though. Winds should be light-to-breezy out of the SW. Overnight lows should fall to the 30-40 range from NNJ elevations to SNJ coasts.  

Wednesday (Dec 18) high temperatures should range from 45-55 from NNJ elevations to SNJ coasts. Skies should start calm and clear but increase in cloudiness through PM hours. Rain is possible for PM hours especially overnight into Thursday morning. Winds should be light out of the S/SE away from the ocean and breezy, possibly gusty at times, out of the S/SE along the SENJ coast. Overnight lows should hover statewide around 40 as rain persists into Thursday morning.

Thursday (Dec 19) high temperatures should only reach the low-to-mid 40s for most NJ locations…a transition day back to a colder air mass. Any rainfall should end by daybreak with conditions improving throughout the day. Winds should be light-to-breezy out of the N/NW. Overnight lows should range from 20-35 from NNJ elevations to SNJ coasts (most of NJ down into the 20s).

Friday (Dec 20) high temperatures should range from 35-45 from NNJ elevations to SNJ coasts. Skies should be mixed with sun and clouds. Can’t rule out a passing shower…better chance of snow mixing in the further NW you are during the day. Winds should be light out of the N/NE. Overnight lows should range from 20-30 from NNJ elevations to SNJ coasts. Any leftover showers would likely fall as snow overnight. Little-to-no accumulation is expected.

An early look at the weekend (Dec 21-22) indicates a further step-down in cold. We’re talking highs in the 20s/30s and lows in the single digits/teens…and this should last right into Christmas Eve. I have lost significant confidence in a larger storm right before Christmas. But I’m still tracking possible snow showers in that Dec 21-23 period. A warmup is then starting to show between Christmas Day and New Year’s Day before a very cold opening to 2025. 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 discussion and forecasting services for New Jersey and surrounding areas through the web and social media. Originally branded as Severe NJ Weather (before 2014), Weather NJ is proud to bring you accurate and responsible forecast discussion ahead of high-stakes weather scenarios that impact this great garden state of ours. All Weather. All New Jersey.™ Be safe! JC