Thunderstorms, Unhealthy Air, Heat: MA In For Miserable Weather Day

MASSACHUSETTS — Thursday will be a challenging weather day in Massachusetts, with the expected peak of this week's heat wave, plus air quality alerts and the chance for thunderstorms.

A heat advisory will be in effect until 7 p.m. Thursday, with heat indices expected to reach around 102 in some parts of the state. Places like the Merrimack and Connecticut River valleys could see the worst of the heat.

There's also an air quality advisory in effect for almost the entire state, including the Worcester area, Boston area and as far south as Fall River.

"An Air Quality Alert means that ground level ozone concentrations within the region may approach or exceed levels that are unhealthy for sensitive groups," the National Weather Service said. "Air is unhealthy for sensitive children and adults, such as those with asthma, lung or heart disease, and older adults. Sensitive children and adults should limit prolonged outdoor activity."

Thunderstorms could begin around 5 p.m. in the Worcester area, moving east and southeast from there. But the worst of the storms may not come until a second wave arrives around 9 p.m. and continues through midnight, according to forecasts. The National Weather Service's Storm Predication Center put the chance of severe storms at about 10 percent for Massachusetts.

Although temperatures will start to fall by Friday, the weather outlook for the next few days isn't great. There's a chance of thunderstorms again on Friday evening, and then about a 50 percent chance of showers for both weekend days. Temperatures will also start to rise to near 90 in eastern parts of the state by Sunday, according to forecasts.