Goodbye, cool world. After a mild start, Massachusetts will get a blast of summer heat this week that will drive temperatures in some areas to nearly 100 degrees on Thursday, forecasters say.

Temperatures today only reached the low 60s in Boston, and they’re expected to drop to the mid-50s tonight. But the weather will warm up beginning Tuesday and the heat will crescendo on Thursday, according to the National Weather Service.

Temperatures Tuesday will rise to 84 in Western Massachusetts and the mid-60s to low 70s near the coast. Clouds in the morning will make way for sun as the day continues.

Wednesday is going to be hot and humid. Temperatures will climb into the mid-90s, though they’ll be somewhat cooler along the coast, and skies will be partly cloudy.

Thursday will be even warmer, with highs reaching 88 in Boston and high humidity.

More than a few places in the interior — across the Connecticut and Merrimack River valleys — could approach 100 degrees, the forecasters said.

Massachusetts Emergency Management Agency officials today released tips for dealing with the extreme heat.

MEMA Director Kurt Schwartz urged caution. “A few common sense measures can reduce heat-related problems, especially for the elderly, the very young, and people with respiratory ailments, who are more susceptible to the effects of high temperatures,” he said in a statement.

People should stay indoors, drink plenty of water, and avoid strenuous activity, MEMA officials said. They also reminded Massachusetts residents not to leave children or pets alone in vehicles and stressed the importance of checking on neighbors, family members, and friends.

Friday will be milder. Scattered thunderstorms could erupt as highs recede to the upper 70s near the coast and the upper 80s inland.

The weekend will be a bit cooler and partly sunny with a high of about 70 in Boston and the low 80s in Western Massachusetts. Rain could arrive on Sunday.