A massive heat dome is hanging over the eastern part of the nation — kicking off a prolonged, dangerous heat wave for all of New England this Fourth of July week, including Boston, that will drive temperatures 20 to 30 degrees above average to triple digits and send humidity soaring.

Another heat wave is in sight in Middle Tennessee. We recently closed out our second heat wave of the year and it was a major one, lasting a full week. A new record-high temperature was set on Friday,

Summer camp and other outdoor activities were canceled or delayed Monday as a heat wave held its grip on the Midwest and spread eastward. Communities opened cooling centers and urged people to take it easy and stay hydrated.

Extreme heat warnings and heat advisories were issued Monday for the entire Chicago area, with hot, sweltering temperatures in the 90s and even higher humidity expected to last through at least Wednesday.

A StormTeam 5 weather alert remains through Saturday because of the heat, humidity and a risk of evening storms.

The most intense conditions are happening in Britain, France and Spain, which are all under high-level heat warnings.