Discussion: The strong area of high pressure responsible for the cold this week will ultimately be responsible for the moderation in temperature between Thursday and Saturday night. The front side of the high’s anti-cyclonic flow brought cold from the N and the back side (once it tracks E of NJ longitude) will bring warmer temperatures up from the S behind it. Thursday-Saturday is a transient moderation as temperatures are expected to return to the overall prolonged cold pattern Sunday into next week. This Thursday-Saturday period however also coincides with weather system expected to impact NJ with precipitation Saturday into Sunday.
We’re dealing with an upper-level low that will be trapped between a split-flow pattern. The jets will ultimately guide this ULL eastward over the Mid-Atlantic US but it should track very abnormally while doing so. A surface low will form in relation to the ULL which will ultimately bring us our disturbance.
The NJ surface temperature profile looks very marginal throughout this system meaning slightly-above freezing for most areas. Currently I only see wintry concern for extreme NNJ (N of I-80/NW of I-287). Sussex County is favored as ground zero wintry-wise. The rest of NJ (S of I-80/SE of I-287) is likely looking at a cold rain with temperatures in the mid-to-upper 30s even lower-40s. With that said some of the model guidance is suggesting double-digit accumulations for Sussex County especially the higher elevation microclimate which behaves more like the Poconos and Catskills.
Given the uncertainty of the exact ULL track it is very hard to pin down expected wintry accumulations for NNJ. I imagine the model guidance will change many times between now and Saturday. It might bring more of NJ into the snow (maybe down to I-78). It might bring less. We likely won’t have wintry-impact maps out until Thursday. But for the rest of NJ (NENJ, all of CNJ and SNJ) this system seems too warm for a snowstorm. I’ll check back each day and report on the extreme NNJ wintry expectations.
In English: Temperatures should moderate milder Thursday-Saturday. A system should then float through from W to E between Saturday and Sunday bringing rain to most of NJ but possibly snow accumulations to NNJ (especially NWNJ). I’ll also be monitoring any coastal flooding aspects that may impact ECNJ/SENJ via prolonged onshore flow. We’ll have a much better handle on this by Thursday but for now just know that the weekend does not look dry and clear. Have a great Tuesday night and please be safe! JC
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