NYC CP first measurable minor snowfall? 11A Fri 12/20-11A 12/21, embedded with surrounding area periodic minor accumulative snow

wdrag · 2024-12-18T13:06:13Z

No guarantees on what will happen. Modeling showa a pair of closely following short waves diving southeast toward the mid Atlantic coast, sharpening the mid level trough. While too far offshore for a 4+" event, the 850 MB weak warm advection, 850MB vorticity from s central NYS sewd to NNJ and under running boundary layer northerly flow is going to produce a little bit of snow.

For CP, think it needs to measure after sundown Fri. Outskirts of NYC from NNJ-se NYS-sw CT across LI should see 1/4" to maybe as much as 2", with potential for 3" near the NYS-PA nw NJ border.

4AM NWS has not posted any snowfall for NYC, so the probability (attached) for 0.1" in CP is very low (26%).

Added 08z WSSI-P graphic and the NWS 08z/18 Blend of Models.

If the system ends up weaker and not sharpening, then this modeled event fritters (850 vort trough just becomes general northerly CAA flow instead of what is modeled now). Should the miD level trough sharpen a bit more then that boosts confidence for NYC metro spirits brightened by snow on the ground Saturday morning.

If PHL measures, that would be their first of the year. BOS already has measured.

Reserving comment for Christmas possibilities to the general Dec thread for now, will we get through 12z Sat. Click graphics for clarity.805A