'Dangerous Heat' Coming To MA: See Expected High Temperatures

MASSACHUSETTS — A heat advisory covering most of Massachusetts will go into effect Thursday with heat indices predicted to reach near 100, the first sustained stretch of potentially dangerous heat so far this summer.

A heat advisory begins at 11 a.m. Thursday and will last until Friday night for all parts of Massachusetts east of the Berkshires. The heat advisory is meant to put residents on alert about heat-related illnesses, like heat stroke and dehydration.

In general, coastal areas from Boston to New Bedford will see heat indices approaching 100 degrees. Slightly cooler temperatures will be felt in the central part of the state, with the Worcester area expected to see values in the low 90s.

"Highs mid 80s to low 90s. Dangerous heat late this week into Saturday. Make sure to stay cool & hydrated!" the National Weather Service office in Norton tweeted Wednesday morning.

Next to the wave of heat, the state will also be at an elevated risk of more severe thunderstorms on Thursday afternoon. An unsettled system approaching from the Great Lakes will collide with the hot air sitting over the region, creating the potential for storms that are "more organized than most instances of severe weather," the weather service said in a forecast Wednesday.

Some forecasts, including from NBC Boston, have mentioned the slight risk of spin-up tornadoes, which form when two weather systems collide. The tornado this month in North Brookfield likely occurred in that fashion.

Forecasters are waiting to see how the storms behave over the Great Lakes before making predictions about Thursday's storms in Massachusetts, which will arrive potentially in the late afternoon and evening hours.

Here's a look at some expected local heat index values coming up, according to the weather service: