Wind Advisory: Big 40+ mph wind gusts to blow through NJ Saturday
The Bottom Line
Although Saturday will turn into a fairly warm and mainly dry day, New Jersey will end up pretty windswept too. Gusts will almost certainly top 40 mph, and may reach 60+ mph within the next 24 hours.
Those big winds will blow alongside a big weather transition, thanks to the passage of a warm front and then a strong cold front. We'll progress from record warmth, to rainy and stormy weather, to a big cooldown.
So batten down the hatches, the garbage cans, and the Christmas decorations for sure. Let's break down the 3-part timeline of this active weather day, and talk about how the wind (and some rain) could get nasty.
Stage 1: Warm South Wind
High temperatures on Saturday will soar into the 60s (at least), threatening records across the state. (Record highs for December 11: 65° at Newark, 65° at Trenton, 66° at Atlantic City.)
Saturday morning will probably be the "tamest" time of the day, in terms of the wind potential. A strong low-level jet will develop way above our heads. But there will not be a great "trigger" to mix those strong winds down to the surface. So for Saturday's daytime hours, let's call it "increasingly breezy". Wind gusts may touch 30+ mph in the afternoon.
Agreeing with that timeline, National Weather Service has issued a Wind Advisory for all 21 counties in New Jersey:
—from 1 p.m. Saturday to 1 a.m. Sunday... Atlantic, Burlington, Camden, Cape May, Cumberland, Gloucester, Mercer, Middlesex, Monmouth, Ocean, and Salem.
—from 3 p.m. Saturday to 4 a.m. Sunday... Bergen, Essex, Hudson, Passaic, and Union.
—from 4 p.m. Saturday to 1 a.m. Sunday... Hunterdon, Morris, Somerset, Sussex, and Warren.
Meanwhile, skies will be mostly cloudy to overcast throughout Saturday. We'll continue to see some spotty rain showers and patchy dense fog around through the morning hours, especially in North Jersey.
Stage 2: Thunderstorms
A "cold front" is the leading boundary of a colder air mass. The density difference of cold air overtaking warm air generates "lift" in the atmosphere. And lift causes precipitation.
So, as a strong cold front approaches Saturday evening, a line of rain will sweep across New Jersey from west to east. Everyone in the state will experience a brief, although potentially potent round of wet weather.
Most likely timing for a narrow band of heavy rain looks to come between 6 p.m. and Midnight Saturday evening. Lighter rain may linger through early Sunday morning.
Because of the relative warmth and moisture in the atmosphere, there is a good chance of some embedded thunderstorms. (Yes, thunderstorms are rare in December, but they do happen.) Given the copious wind shear, there is a concern that some of those storms could reach strong (40+ mph) to severe (58+ mph) limits.
The Storm Prediction Center has painted most of New Jersey in a marginal risk for severe weather. That is the lowest of five levels on their scale. The biggest concern, by far, is for straight-line winds (i.e. "gusty thunderstorms"). An isolated tornado can't be ruled out.
Note: According to the NJ State Climate Office, New Jersey has never experienced a tornado in the month of December since detailed record-keeping began in 1950. (Nor in January, for that matter.)
Additional note: This storm system is the same one that caused an incredibly destructive severe weather outbreak through the Midwest Friday night. SPC shows 36 tornado reports through Missouri, Tennessee, Kentucky, Arkansas, and Illinois. It absolutely will not have the same "oomph" as it flies by New Jersey on Saturday, but that history is ominous.
So please keep your eye on the sky Saturday evening for stormy weather. When thunder roars, it's time to head inside a sturdy building. (Also, to be clear, there is zero chance of wintry weather from this storm system.)
Stage 3: The Big Cooldown
Probably the broadest winds of the day will come from the grand finale cooldown, arriving late Saturday evening (I'd estimate between about 9 p.m. and Midnight) The wind will flip to blow out of the west-northwest, driving a new, colder, drier air mass into New Jersey.
This is the point of the day where top wind gusts are most likely to push into the 40 to 60 mph range. Potentially causing downed trees and branches, power outages, driving difficulties, relocated garbage cans, etc.
The big takeaway: Saturday evening is not going to be a good time to be out and about. The potential for strong thunderstorms then big wind gusts could make things nasty for a while.
The Extended Forecast
A huge area of high pressure will settle over the mid-Atlantic for Sunday and beyond. That protective dome of sinking air will keep storm systems away and make our skies beautifully blue.
Sunday will be breezy and cooler. But not too cold — highs in the mid-upper 40s are pretty typical here in mid-December.
Monday and Tuesday should be very nice days, with highs pushing into the 50s.
Clouds and a shower are possible on Wednesday. But our next large-scale storm system is almost a week away. And the next threat of substantial snowfall is more like a week and a half into the future.
Be smart and stay safe out there Saturday. The nice weather payoff next week is going to be great. But we have to get there first.