Get those air conditioners tuned up. The first widespread heat wave of the year is on the way, and people all across New Jersey will be noticing the humidity levels creeping up as the long Fourth of July holiday "weekend" approaches.

"It's not going to be so much the high temperature but the humidity" that will make people feel uncomfortable outside, said Alex Staarmann, a meteorologist at the National Weather Service's regional forecast office in New Jersey.

In most inland areas, the thermometer is expected to reach the low 90s on Friday before rising into the mid-90s on Saturday and Sunday. Although that probably won't be hot enough to break any daily temperature records, the air will be saturated, making it feel like it's between 100 and 105 degrees away from the coast.

In the Newark region and in other northeastern sections of New Jersey, the mercury could make a run for triple digits on Sunday, said David Stark, a meteorologist at the weather service office in Upton, N.Y., which covers Bergen, Essex, Hudson, Passaic and Union counties.

"It's not a guarantee, but it's possible that the actual temperature touches 100 in Newark on Sunday," Stark said. For now, the weather service is projecting a high of 99 degrees in Newark.

Even if that forecast falls short by a few degrees, the humidity will make it feel as hot as 104 to 107 degrees in much of northeastern New Jersey on Sunday, Stark noted.

Relief at the beach

A good option for relief will be along the Jersey Shore, where temperatures will be hovering in the low to mid-80s this weekend.

"It will be a little cooler at the beaches, but it will still be humid," Staarmann noted.

Don't expect much cloud cover to block the blazing hot sun this weekend. Mostly clear skies are forecast for Friday, Saturday and Sunday both inland and along the Shore.

The early long-range forecast calls for a mix of sun and clouds on Monday, Tuesday and Wednesday -- when Independence Day is being celebrated -- with a 30 percent to 40 percent chance of showers or thunderstorms those three days.

Temperatures in interior sections of New Jersey could remain at or near 90 on Monday and Tuesday before retreating to the upper 80s on Wednesday.

Cooling down in the heatwave like... pic.twitter.com/YO7nZR7QAV — Animal Bible (@AN1MALBIBLE) June 27, 2018

Heat wave No. 2

For a few areas of New Jersey, including Newark, the approaching heat wave will be the second one of the year. But for most parts of the state, this will be the first one, with three straight days of 90-degree temperatures expected.

Newark's first heat wave of 2018 was recorded on June 17, June 18 and June 19, when temperatures reached 91 degrees, 96 degrees and 90 degrees.

Len Melisurgo may be reached at LMelisurgo@njadvancemedia.com. Follow him on Twitter @LensReality or like him on Facebook. Find NJ.com on Facebook.