A heat advisory is in effect in Boston and several other Massachusetts communities through 7 p.m. on July 17. The National Weather Service warned of "dangerous heat and humidity" with heat indices soaring to 95 to 100 degrees. Boston Mayor Michelle Wu also declared a heat emergency for the City of Boston from July 16 to 18.

Mayor Michelle Wu declared a heat emergency for Boston from Wednesday through Friday, with the heat index predicted to fluctuate from 91 to 97 degrees with little overnight relief, the city announced.

As another bout of sweltering heat is set to hit Massachusetts, the MBTA is alerting riders that the extreme heat could cause delays on the commuter rail on Friday.

A heat advisory has been issued in parts of Massachusetts through the end of the week as temperatures start to rise.

National Weather Service forecasters also warned of a "handful" of strong to severe thunderstorms on Friday afternoon.

Boston faces a hot Thursday with a Heat Advisory; relief and cooler temperatures are expected after a cold front with potential rain and thunderstorms later in the day.

The Boston region is in for sweltering temperatures as this week kicks off before chances of rain and storms appear on and off as the days go on, according to National Weather Service forecasts.

A heat advisory goes into effect Thursday for parts of Connecticut where heat index values will soar past 100 degrees on Friday.

Boston is facing a heatwave with feels-like temperatures reaching up to 100 degrees, and a heat advisory is in effect.