Massachusetts To See Day Of Harsh Weather: Severe Storms, Extreme Heat

UPDATE: A Severe Thunderstorm Watch has been issued across much of southern New England through 8 p.m., the National Weather Service announced. "If you have outdoor plans, have a safe place to go (preferably indoors) if threatening weather approaches," the weather service said in a Wednesday afternoon tweet.

Severe Thunderstorm Watch in effect until 8 PM for much of southern New England.

Stay weather aware & have a way to receive warnings.

If you have outdoor plans, have a safe place to go (preferably indoors) if threatening weather approaches. #ctwx #mawx #riwx pic.twitter.com/eVXtZg25pd
— NWS Boston (@NWSBoston) July 27, 2023

Additionally, parts of New Hampshire, including Cheshire County and Hillsborough County, are under a tornado warning through 3:15 p.m.

This is a developing story and will be updated.

Original story:

MASSACHUSETTS — Prepare for a day of weather extremes across Massachusetts.

Almost the entire state is under multiple weather advisories Thursday, including a flood watch, heat advisory, a high surf advisory and the chance for tornadoes, according to the National Weather Service.

Here's a breakdown of the various hazards to be aware of today:

Heat

The entire state except the Berkshires will be under a heat advisory starting at 11 a.m. due to possible heat index values between 95 and 100. The heat index is a measure of how hot it feels through a combination of air temperature and humidity.

In general, parts of the state from Boston through the Merrimack Valley will see the highest heat index values through Saturday.

The heat advisory will be in effect until Saturday night, and the advisory is meant to alert people to stay cool and hydrated, and to keep an eye on vulnerable relatives like children, the elderly and people with chronic illnesses. Many cities and towns are opening cooling centers at libraries and other community buildings to help residents escape dangerous heat.

Tornadoes

This afternoon, the hot air will collide with a weather system moving in from the Great Lakes, creating the potential for severe thunderstorms and tornadoes. There's about a 5 percent chance of tornado activity in parts of the state this afternoon, according to NWS.

"To emphasize: this is a severe weather setting which is uncommonly experienced in Southern New England, and the potential for brief tornadoes and straight-line wind damage is a credible risk in environments like this one. If you do have plans outdoors, it's vital to keep an eye to the sky and to have multiple ways to receive [weather] statements, and that's especially true in western interior sections of MA and CT where the greatest potential for severe weather exists," the weather service said in a forecast Thursday morning.

Expect severe storms between noon and 9 p.m. on Thursday.

Flooding

Along with the severe storms comes the risk of flooding. The ground has been saturated by heavy rain in recent weeks, making it easy for flash floods to begin. Flash floods have inundated parts of the state along the Connecticut River, and even landmarks like Storrow Drive and Fenway Park in Boston in recent weeks.

A flood watch is in effect Thursday starting at 11 a.m. for most major population centers in the state, including Boston, Worcester, Lowell and Springfield.

Ocean dangers

If you're planning to head to the beach Thursday to escape the heat, keep an eye on ocean currents. There's a high surf advisory in effect for ocean beaches from Plymouth to Provincetown with riptides and waves up to 6 feet expected. A high surf advisory is in effect from 8 a.m. to 8 p.m. for southern Plymouth County, Barnstable County and Dukes County.