Nov 12: Winter Weather Update

Jonathan Carr
By November 12, 2014 10:21

Nov 12: Winter Weather Update

We’re approaching the Arctic outbreak and light snow possibilities that I’ve been discussing in the past few weeks. Remnants of Typhoon Nuri went on to become the strongest Bering Sea storm on record. That energy pushed up into the Alaskan polar regions of the northern hemisphere and in return, plunged arctic air mass southward into the central and eastern US. The frontal boundary of this colder air mass is approaching the east coast and will be through by early tomorrow morning.

Here on this SimuAwips image, you can see the temperature difference line set up over the Appalachian Mountains and moving east. You can also see the two big synoptic players of this US pattern. The low over eastern Canada spins counter-clockwise while the arctic high over Wyoming (black = below zero) spins clockwise. This has opened the gates to energy that has broken off of the Polar Vortex (not “THE” Polar Vortex). The blue wind indicators also show you wind direction/intensity:

arctic frontal boundary showing on simuawips

Now lets talk about the first light snow possibility. This is not a big deal…a “nuisance at most” with only trace-minor accumulations expected. Perhaps a few inches in the higher elevations of NWNJ and a coating to the coast on non-paved surfaces. It should start as light rain in the evening and change over to snow by midnight. Don’t be wearing pajamas inside out for a snow day on Friday though…not happening! Festive? sure! Disruptive? No.  Here it is on the new upgraded GFS. This map shows 850mb pressure, temperature, and precipitation that has fallen between 7PM Thursday evening and 1AM Friday morning. As you can see,  a weak coastal low will be moving by and throwing moisture onshore:

upgraded gfs showing possible snow on Thursday night - Friday morning

The next possibility is more interesting to me. This should occur this coming Monday-Tuesday. A stronger and better-defined low pressure system looks to form in the Gulf of Mexico and ride up the east coast and throw a decent amount of moisture inland. Guidance has been consistent on timing and precipitation amounts. The wildcard is where the snow/rain line will set up. I could see this being snow for NWNJ and cold rain for everyone else should lower level temperatures moderate too quickly. On the contrary, if the arctic boundary holds stubborn (like it did many times last year), then the snow/rain line could be further SE towards I-95. Regardless, I think coastal and SENJ see all rain with this one. The battleground between snow and rain will likely be inland. Here’s same upgraded GFS model/parameters as above but for 2PM through 7PM on Monday.

upgraded gfs showing rain and snow for Sunday-Tuesday over New Jersey

In English: The cold is coming and will be here for tomorrow. It could snow lightly Thursday night into early Friday morning with little to no accumulations expected. It could snow again NW of I-95 and rain SE of I-95 on Monday with accumulations only likely for interior/higher elevations of NWNJ. The rest of the weather (statewide), that surrounds these winter weather headlines into next week, will be cold and dry. Bundle up and be safe! JC

Jonathan Carr
By November 12, 2014 10:21