With oppressive heat and humidity making it feel close to 100 degrees, Bay State officials are warning residents about the risk for heat stroke and heat exhaustion, while they extend hours at swimming pools, beaches, waterfronts and spray decks.

The National Weather Service has issued a heat advisory for Massachusetts with heat-index values of 95 to 104 degrees on Thursday and Friday afternoon. A heat emergency has been declared for Boston.

To help residents beat the heat, the state Department of Recreation and Conservation has extended lifeguard and operating hours at agency-managed pools, beaches, waterfronts, wading pools and spray decks by one hour.

DCR pools will be closing at 7:45 p.m.; beaches and waterfronts will be guarded until 6:45 p.m.; wading pools will operate until 7 p.m.; and spray decks will run until 9 p.m.

“As Massachusetts will experience some of its most intense heat in the coming days, it’s important for people to make a plan to stay safe — including staying hydrated, limiting strenuous activity, and checking in on one another,” said Gov. Maura Healey.

“We’ve expanded hours at DCR swimming pools, beaches, waterfronts and spray decks to allow for more opportunities for residents to cool off,” the governor added. “We’re grateful to the workers who are putting in the time and effort to support these extended hours. All of us can do our part to help our friends and neighbors beat the heat.”

Oppressive hot temps and high humidity may spark heat illnesses in the next couple of days, meteorologists and officials warn.

“The members of Local 718 remain prepared to continue their diligent service to the citizens of Boston as we expect an increase in heat-related emergencies,” Boston Firefighters Local 718 tweeted.

So how can you stay cool when the temps spike to triple digits? Here are some extreme heat safety tips:

Meanwhile, if the heat wasn’t enough, the region will be facing a risk for severe thunderstorms and torrential rain on Thursday afternoon and evening. The ground is incredibly saturated from all the recent rain, so there will be a flooding risk on Thursday.

“Some of these storms may become severe,” the National Weather Service’s Boston office tweeted. “The primary threat is damaging straight line wind gusts and localized flash flooding. But a Tornado is also possible.”