Severe Thunderstorm Watch for NJ: Heavy rain, gusty winds likely Saturday

The past three weeks have featured some quiet, beautiful weather across New Jersey. But Saturday will be anything but.

The air is warm and very humid, with temperatures in the 80s and dew points in the 70s. That juicy atmosphere will combine with the lift of an approaching cold front to support several rounds of thunderstorms. Those storms are likely to reach strong or severe limits.

The National Weather Service and Storm Prediction Center have issued a Severe Thunderstorm Watch for 20 of New Jersey's 21 counties — all but Cape May County — until 8 p.m. Saturday.

A watch serves as a formal heads-up that dangerous weather may occur. While it is not a guarantee that nasty storms will affect the entire area, everyone should be ready to seek shelter in case warnings are issued.

As of 1 p.m. Saturday afternoon, spotty showers and thunderstorms have started to invade northwestern New Jersey. As the afternoon presses on, they will spread through the rest of the day.

Prime time for severe weather will be from mid-afternoon through this evening. Let's say 3 p.m. to 9 p.m.

My biggest concern here is probably for downpours. Yes, we need the rain given spiralling drought and wildfire concerns. But too much heavy rain in too short a period of time can lead to serious flooding issues. Models suggest NJ rainfall will range from a quarter-inch (at the minimum) to 2 or 3+ inches (in pockets). I expect most of the state will see over an inch of rain by the end of the day.

The second biggest concern from Saturday's storms is for gusty winds, which could bring down trees and power lines. Followed immediately by cloud-to-ground lightning which, by definition, makes every thunderstorm dangerous.

Hail and/or an isolated tornado can not be ruled out in this kind of explosive atmosphere.

Needless to say, it is very important to stay "weather aware" and keep a close eye on the sky through Saturday afternoon. Especially if you have outdoor activities or travel plans. When the sky darkens up and/or when you can hear thunder, it is time to head inside.

While the threat for severe weather will wrap up by late evening, lingering rain may continue until Sunday morning. Then, as skies clear and humidity drops sharply, we will be treated to a refreshing end to the weekend. Sunday afternoon should feature sunshine and highs back down in the 70s.

Be smart and stay safe out there.

Dan Zarrow is Chief Meteorologist for Townsquare Media New Jersey. Follow him on Facebook for the latest forecast and realtime weather updates.