Dec 11: Sneaky Thursday PM Snow

Discussion: Every once in a while a sneaky light snow event comes out of nowhere. It might be from ocean-effect snow, a larger system trailing mid-level (700-850mb) disturbance, a strong lake-effect squall, etc. In the case of this Thursday PM it might be in the form of an upper-level disturbance. Currently an upper-level shortwave is developing in the NW US. Per recent data trends this should develop into a weak but closed-off upper level low over the Great Lakes by this Wednesday afternoon. This should eject into the Atlantic Ocean by early Friday morning somewhere between NJ and Long Island. That about covers the 500mb look.

At the surface we should see a blob of precipitation move in like a clipper between Thursday afternoon and evening. The lower-level temperature profile would indicate a snow/rain line somewhere in the I-95 to I-78 area. With that said, NNJ would be most favored for snow, northern CNJ would be most favored for the snow/rain line and southern CNJ/SNJ would be most favored for light rainfall. We’re no talking about a super-wet system here. Only between a tenth of an inch and a fifth of an inch of liquid is modeled to fall. At 10:1 snow ratios you’re talking 1-2 inches of light snow, maybe 2-4 inches with a worst-case over-performance. Given how the first few snowfalls have gone this year, it might be a good idea to prepare for the maximum light snow event scenario. Upper-level instability seems to perform better with these kinds of events. And again this will likely be only for NNJ and parts of CNJ, NOT the southern part of CNJ or SNJ.  We still have a little over 48 hours until this now-expected system moves in from the W. Let’s see how it evolves in the meantime.

In English: A light snow event is increasing in likelihood for this Thursday during PM hours. This currently looks like snow for NNJ, a snow/rain line in the northern part of CNJ (somewhere near I-78 to I-95/NJTP) and mostly cold rain for SNJ. For areas that do see snow, I would expect a widespread coating to 2 inches with the possibility for localized higher amounts (nothing crazy). Afterwards we should commence with the milder temps and statewide weekend rainfall. Let’s revisit this tomorrow with fresh data. I’ll keep you posted. Have a great rest of your Tuesday and please be safe! JC

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 and social media. 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.™