Wow, what a wild week of wintry (and wet and windy) weather
The Bottom Line
We're tracking a dynamic duo of winter storms this week. A minor one Monday. A more significant, more impactful nor'easter Wednesday into Thursday.
Monday's system is going to bring mainly rain to New Jersey, with limited snow accumulations to the northwest.
It's really the Wednesday-Thursday storm we're focusing on here. The big picture is becoming clear: It is going to hit New Jersey. And we can now piece together a rough timeline, which is the focus of this post. However, the precise details of snow vs. ice vs. rain and accumulations remain highly uncertain.
I have produced an initial snowfall map for the midweek nor'easter. Confidence is low. I fully realize how utterly ridiculous it is to forecast "2 to 10 inches" for that swath of central and southern New Jersey. Please understand that I produced this map to communicate a fuzzy idea of the overall geography here: the area most likely to receive heavy snow, the area that is most uncertain, and the area that will experience primarily rain. This map will change in the coming days and hours, as the temperature forecast and storm track continue to evolve. A shift in 50 to 100 miles will make an enormous difference here.
As of this writing, initial rain showers from storm system #1 have arrived in New Jersey. Yes, just rain.
And we'll see raindrops overspread the entire state by around 10 a.m. Monday. Yes, just raindrops.
As temperatures slowly fall below the freezing mark in North Jersey (both at the surface and aloft), we should see a transition from rain to snow. The area of northwestern NJ north of I-78 and west of I-287 will probably pick up light snow accumulations, on the order of 1 to 3 inches. That is, if the ground isn't too warm (from Sunday's 60s) and/or too wet (from the initial rainfall).
The freezing line will continue to drift south through Monday afternoon, possibly reaching as far south as Interstate 195. So additional spots through central NJ could see snow mix in with rain. It's going to be hard for flakes to stick — but I've included a "Trace to 1 inch" contour in the forecast, just in case.
No advisories have been issued for Monday's rain/snow.
Temperatures will slowly fall as the day goes on, ending up in the mid 30s (north) to mid 40s (south) by sundown.
Precipitation will exit the state for good in the early evening hours, around dinnertime. Clearing skies and cold temperatures are expected Monday night, with lows in the 20s.
Quiet. Mostly sunny, with late-day clouds. High temperatures will only reach about 35 to 40 degrees — 5 below normal for mid-December.
According to the latest forecast model guidance, Wednesday morning looks fine. Things will start to go downhill as first snowflakes and raindrops arrive in the midday to afternoon hours. The storm will peak from Wednesday evening through early Thursday morning — basically, the heaviest snow/mix/rain and strongest winds will come at night. And then the storm exits sometime Thursday morning. (There are some model differences as to whether the end time is closer to 5 a.m. or 11 a.m.)
In terms of impacts, I'm thinking big double-digit snowfall is likely for part of New Jersey, especially along and west of the NJ Turnpike corridor. A classic nor'easter setup. Initial rain to the south and along the coast should eventually change over to accumulating snow (at least briefly) by Thursday morning. I still think there will be a sharp gradient between "boom and bust" snowfall — drive just ten miles westbound on I-195, and there could be a huge difference in snow totals.
But this storm is not just about the snow. Those along the coast should expect 1 to 2 inches of total rainfall. There could be some visibility, traction, and ponding issues there.
At least one model (the NAM) paints a significant period of sleet and freezing rain during the peak of the storm. That would ultimately reduce snow totals (perhaps dramatically), but produce even-more-dangerous icing conditions.
As the center of this strong (and strengthening low pressure) passes just off the coast, a period of 40-50 mph wind gusts seems likely. Power outages would be highly convenient.
And coastal flooding is a concern too, starting with Thursday morning's high tide cycle. About 2 feet of storm surge could cause widespread moderate category flooding of tidal waterways. Maybe even reaching "major" flood stage in spots?
A Winter Storm Watch has already been issued for much of inland New Jersey, technically in effect from 7 a.m. Wednesday to 7 a.m. Thursday. That watch includes Sussex, Warren, Morris, Hunterdon, Somerset, Mercer, Middlesex, inland Monmouth, northwestern Burlington, Camden, Gloucester, and Salem counties. Warnings and advisories will likely be issued ahead of the storm on Tuesday.
After the storm, the sun will emerge quickly. And temperatures will go absolutely nowhere. Highs will only reach the lower 30s on Thursday.
Friday & Beyond
Friday will be a cold, winterish day. Morning lows in the teens. Afternoon highs in the mid 30s. Bright sunshine and very dry air.
Our next storm system will be a front arriving on Sunday. Right now, models just show some rain and snow showers. There could be some light accumulations, perhaps. For now, no big deal.
A cool, quiet weather pattern will resume early next week.