Dangerous heat, humidity to blanket Massachusetts beginning Tuesday

The first heat wave of the season will descend on Massachusetts Tuesday, bringing with it dangerously high temperatures that forecasters said could set records for the Bay State.

Already, the warm-up has begun. Apparent temperatures, essentially a “feels like” value, for Boston, Worcester and Springfield were all set to be above 80 degrees by around 6 a.m. Tuesday, according to the National Weather Service. From there, temperatures are set to spike in the afternoon, with forecasters projecting apparent temperatures well above 90 degrees in all three cities.

But Tuesday is far from the worst of it.

“Dangerous heat and humidity … peaks in the Wednesday through Friday time frame,” National Weather Service forecasters wrote. “Near to record breaking high temperatures are possible.”

A heat wave for the northeast is defined as three or more consecutive days of at least 90-degree temperatures, according to AccuWeather. The way the forecast is shaping up, Massachusetts could see four days of temperatures that high.

In Boston, the projected high temperatures for the remainder of the work week are 94, 95, 97 and 89. In Worcester, the highs are forecasted at 94, 94, 96 and 93. And in Springfield, it will be even warmer, with temperatures of 94, 95, 98 and 95 projected.

The heat prompted Boston Mayor Michelle Wu to declare a heat emergency from Tuesday to Thursday, and led to Worcester Public Schools opting to shut its doors early, canceling school on Thursday.

While summertime does bring with it warmer temperatures, a heat wave of this kind is unusual so early in the season, according to AccuWeather.

“Although high heat is not uncommon … during the summer months, the fact that this heat wave is projected to be particularly long and intense and occurring so early in the season is particularly notable,” AccuWeather Meteorologist Renee Duff wrote.

Some areas of the state will be spared the worst of the warm weather.

The South Coast and the Cape and Islands are the only areas of Massachusetts not under a Heat Advisory on Tuesday. On the South Coast, highs are projected in the 80s, while the Cape and Islands will see highs around 70 degrees.

Relief could finally come over the weekend, but forecasters said it will remain muggy on both Saturday and Sunday, with a chance for afternoon showers and thunderstorms.