Rain to Icy Mix (Eventually) for NJ Friday, Flash Freeze Possible
The Bottom Line
Far northern New Jersey will get iced over Friday, as freezing rain, sleet, and a bit of snow make for a wintry day overall. For most of the state, we're starting off with warm and wet conditions — temperatures are in the 50s, with noticeable humidity in the air! That is not going to last all day though. As temperatures tumble into the 30s Friday afternoon, the entire state is prone to see a brief period of icy mix and slippery travel conditions. (The timing of icy mix has slid a bit later for most.) A flash freeze is also a concern for Friday night.
Winter Weather Advisory
The National Weather Service extended their Winter Weather Advisory farther south. Once again, we're not talking about snow here — the concern is for light to moderate icing. It doesn't take much freezing rain and/or sleet to make travel treacherous. Power outages are a possibility too, as the heavy ice weighs down trees, branches, power poles, and power lines.
The advisory covers the following counties for the following times, indicating when you should be "weather aware" and extra careful:
Sussex until 4 p.m.
Morris and Warren from 6 a.m. to 5 p.m.
Bergen, Essex, Passaic, and Union until 7 p.m.
Hudson from 9 a.m. to 7 p.m.
Hunterdon, Mercer, Middlesex, Somerset from 11 a.m. to 7 p.m.
Personally, I think the southward shift in advisories is a bit aggressive. They're playing it safe — again, even a trace of ice can be a huge problem. The threat for substantial icing and really messy roads will be limited to northern New Jersey.
As of this writing (6 a.m.), we're already seeing an icy mix in Sussex and Warren counties with temperatures in the 30s. For the other 19 counties in the state, temperatures are in the 50s, with scattered rain continuing.
The freezing line will slowly drift south throughout the day, forcing more and more towns to flip from rain to icy mix. Prior to the changeover, you'll find periods of rain, heavy at times, with an occasional gusty wind.
Here's an approximate timeline of when areas of New Jersey will dip cold enough for icing conditions. (Keep in mind, the exact precipitation type is difficult to pinpoint, as it depends on temperatures both at the surface and about a mile overhead.)
—Along and North of Interstate 80... Already flipping Friday morning, through about 8 a.m.
—Along and North of Interstate 78... Midday, between about 10 a.m. and 1 p.m.
—Along and North of Interstate 195... Mid to late afternoon, from about 3 p.m. to 6 p.m.
—South Jersey... Evening, between about 6 p.m. to 9 p.m. (just as precipitation is ending for good)
Ice accumulations may near a quarter-inch in and around Sussex County only. Farther south, there could be slippery spots.
By sunset, I expect temperatures to be close to the freezing mark across most of the state. And thermometers will continue plummeting, to around 20 degrees overnight.
Even as rain and icy mix wrap up Friday evening, there will be another concern. (Which may present an even more significant icing concern statewide, by the way.) A flash freeze happens when temperatures dive well below freezing before puddles and wet surfaces have an opportunity to evaporate and drain. That can lead to widespread ice and rapidly deteriorating driving and walking conditions. So watch your step overnight.
We're right back to the cold side of the world, heading into the first weekend of February. Temperatures on Saturday will be stuck below freezing all day. Highs will only reach the upper 20s to around 30 degrees. Skies will become sunny by midday, with a stiff northwest breeze up to 20 mph.
Sunday looks a bit better. Mostly to partly sunny and above-freezing mid 30s. As we've discussed, a clipper system looks to dive well south of New Jersey Sunday night, keeping our weather high and dry.
Seasonable lower 40s are expected Monday. A storm system may clip our southern coastline Monday night — right now, that looks to be a quick round of rain, not snow.
Most of next week looks quiet, with a few near misses. Temperatures will generally hold at or above normal. Our next opportunity for the atmosphere to deliver a "big storm" would be next weekend.