Two weekend weather problems for NJ: Humidity and drenching storms

The Bottom Line

Oh, the humidity! It has been a steamy summer so far. So much so that your electric bill may be off the charts.

But we have largely lucked out on weekends, with very little rain and/or other hazardous weather situations.

That trend is about to change, as the forecast for this first weekend of August is less than perfect. It will be steamy, as disgustingly high humidity combines with unseasonably hot temperatures. And it will be stormy, as several impulses ride through New Jersey's atmosphere.

Given how "juicy" the atmosphere is, any thunderstorm that forms could dump a quick 1 to 2+ inches of rain. That is plenty to raise flooding concerns. Gusty winds are possible from strong storm cells too.

Looking long-range, temperatures will cool down next week. But we will have to watch the cluster of rain that will likely become a tropical storm (Debby) in the next day or two. As that storm system rides up the U.S. East Coast, we could see some rain and surf impacts in the mid to late part of next week.

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Friday

Partly cloudy and 80 degrees. That would make for a delightful mid-June afternoon.

But first thing in the morning? Not a happy start. You know it's going to be another very warm day.

High temperatures on Friday will reach about 90 to 95 degrees. As usual, it will be a few degrees cooler in far northern New Jersey and along the Jersey Shore, in the 80s.

Technically that is a few degrees cooler than Thursday, when we hit 100 degrees in a couple spots (Hamilton and Newark). But humidity will be higher. So the heat index calculation works out the same, feeling like over 100 degrees in many spots Friday afternoon.

An Excessive Heat Warning and Heat Advisory cover all but the immediate coast through Friday evening. Please take care of yourself in this unseasonable, uncomfortable weather.

Weatherwise, we will see times of clouds and sun for the first half of Friday.

Now let's talk about thunderstorms. A hot and humid atmosphere is conducive to explosive storm development. So any storm that comes through New Jersey Friday and this weekend will be capable of producing very heavy rain, in addition to gusty winds.

Initial thunderstorms on Friday could enter the Garden State as early as mid-afternoon, let's say 3 p.m. They will begin to the northwest, spreading south and east through Friday evening. (I would wager on most of NJ seeing storms in the evening hours.). We should see a gradual reduction in storm intensity after sunset. Final thunderstorms probably will not exit the state until after Midnight, early Saturday morning.

Some forecast models are pumping out an inch or two of rain in a brief period of time, which raises serious flooding alarm bells.

Beyond the thunderstorm potential, lingering clouds and some fog will carry through the overnight hours. Low temperatures will only drop into the mid 70s.

Saturday

High humidity takes center stage on Saturday, as dew points surge into the mid 70s. Downright tropical air, making things very uncomfortable statewide. And potentially fueling more thunderstorms.

The first half of Saturdayday will be OK, just sweaty. Expect partly sunny skies and high temperatures around 90 degrees.

Then, again, scattered thunderstorms become likely through the afternoon and evening hours. And again, they will likely be on the strong side, with pockets of heavy stuff around the state. I would pinpoint 3 p.m. to 11 p.m. as the best chance for storms.

Sunday

I am more pessimistic about Sunday's forecast than Saturday's, as the day will be cloudier and rainier overall. You will still catch some breaks, depending where you are and how luck you get.

A few waves of spotty showers and thunderstorms will sweep through New Jersey throughout the day on Sunday. One piece of good news: They are less likely to be severe (i.e. gusty). But storms still could produce localized downpours.

Another highlight of Sunday: It will not be as hot, thanks to the clouds and raindrops. High temperatures will reach about 85 to 90 degrees. Our Jersey heat wave may break. But do not be fooled — it will still be very warm and humid Sunday.

Monday

We look to get a break from the unsettled weather on Monday, although little relief from the summertime heat.

Under mostly sunny skies, high temperatures will again rise into the lower 90s Monday afternoon. Best case scenario, dew points and humidity levels slide backward a little bit.

All forecast models keep Monday dry and storm-free.

Tuesday & Beyond

Our weather forecast gets exponentially trickier by the middle of the week, as a slow-moving front approaches.

There could also be a tropical storm in the neighborhood. A cluster of rain centered over Haiti as of Friday morning will likely develop into a tropical storm as it enters the Gulf of Mexico this weekend. The next name on the list for the Atlantic this year is Debby.

After sliding across Florida, future-Debby will likely parallel the U.S. East Coast for a bit. What it does as it passes North Carolina will have a huge impact on our weather for the middle to late part of next week.

I see three basic scenarios playing out in the Wednesday to Saturday time frame:
1.) Debby flies out to sea. We would see some trough-driven rain, possibly enhanced by some tropical moisture. And surf will be rough for a couple days. But overall impacts would be minor.

2.) Debby stalls off the Carolinas. This could consistently feed tropical moisture our way, leading to persistently rain. Not necessarily heavy stuff, but overall a dreary and drizzly weather pattern. Surf would still be rough in this scenario, likely through next weekend.

3.) Debby beelines for New Jersey-Pennsylvania. Worst-case scenario dumps multiple inches of rain over New Jersey late next week. (Maybe on the order of 4 to 8 inches in spots?) I would not be worried about wind. Storm surge and very rough surf could be significant too.

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