‘Very humid’ Monday across Mass. as temperatures near 90 with chance for thunderstorms

Temperatures across Massachusetts will remain high on Monday, with highs at or near 90 joining with intense humidity to make it feel very warm throughout the state.

National Weather Service forecasters issued a Heat Advisory for almost the entire state, excluding the Berkshires and the South Coast, warning of heat index values as high as 96.

“Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors,” forecasters wrote in the advisory, which is in place until 8 p.m.

As the day turns to afternoon, forecasters expect scattered showers and thunderstorms, particularly in Western Massachusetts and Connecticut. But the exact location of any thunderstorms is unclear, forecasters wrote, and any that do appear are not likely to be severe.

Still, forecasters cautioned the storms have the chance for “heavy downpours and localized flash flooding.”

The greater concern comes on Tuesday, when the unsettled conditions will be more widespread, according to the weather service.

Temperatures will remain in the high 80s to low 90s, with dewpoints in the 70s.

“Can’t rule out an isolated strong to severe storm producing damaging wind gusts,” forecasters wrote. “The greater risk given the weak steering flow and abundant aforementioned moisture … will be heavy downpours leading to flash flooding.”

That said, the region is under only a marginal risk of excess rain leading to flash floods.

Temperatures should fall back to normal by Thursday, with the relief from the heat lasting through the weekend. Even with temperatures dropping, there is still a risk for unsettled weather each day until Friday, with chances for showers and thunderstorms.

There are “hints” of an area of high pressure moving in this weekend, but forecasters say it is still “too soon to nail down timing on this feature.”