Dec 4: Wintry Precipitation Approaching

Jonathan Carr
By December 4, 2016 18:53

Dec 4: Wintry Precipitation Approaching

This will be the last forecast article for this system. Live observations from hereon out…

Two weak systems are passing to our N and S but close enough to enhance precipitation through all of New Jersey overnight and into tomorrow morning. I don’t expect much of anything before midnight tonight. The exact timing window of this event should be between midnight and 8AM tomorrow morning. With that said, areas of wintry precipitation concern should allow a little extra time for the Monday AM commute.

The temperature profile is very marginal, meaning a line of snow/rain should set up somewhere between CNJ and NNJ with NWNJ elevations having the best chance for light accumulations and SNJ/SENJ having the best chance for all cold rain—with everyone between subject to mixed precipitation.

Heavier bursts of precipitation could change rain over to snow for lower elevations, but likely not S of I-195. We saw this a few weeks ago as far south as Ocean/Burlington Counties. Let’s call this the wildcard scenario. Regardless, any surprise accumulations for lower elevations would likely happen on natural surfaces (grass/trees) before paved-surfaces (roads/sidewalks).

Overall, our best guess at a line that divides a light wintry event from a cold rain event is along I-78 from W to E. The area between I-78 and I-195 should most likely see more cold rain than snow but again, precipitation intensity is the wildcard here. With all that said, our collaborative impact map made by both Eastern PA Weather Authority and Weather NJ stands as called from yesterday:

snow map

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In English: Precipitation is currently approaching from the W and should fall between midnight tonight and 8AM tomorrow morning. The higher elevations of NNJ (above 1000ft) have the best chance to see  up to a few inches of snow accumulations. SNJ and especially coastal areas have the best chance to see all rain. CNJ and the lower elevations of NENJ could bounce back and forth between cold rain and a wintry mix depending on precipitation intensity. If more intense then it could change rain over to snow (precipitation brings colder air down). If less intense then cold rain is more likely. To be clear, we are not expecting wintry accumulation S of a line drawn from Trenton to Sandy Hook. Some non-accumulating snow mixed in? Maybe. This is a NNJ/NWNJ light snow event and cold rain for mostly everyone else. It is far from a big deal but could time poorly for the Monday AM commute for said areas. The sun should return for tomorrow. I’ll have the Monday-Friday outlook posted later tonight which will address the Arctic outbreak expected towards the end of the week. Have a great Sunday night and please be safe! JC

Jonathan Carr
By December 4, 2016 18:53