The Massachusetts Emergency Management Agency warned of “torrential downpours that may result in localized flash flooding, especially in urban areas with the greatest risk” across the eastern part of the state into Sunday.
Southeastern Massachusetts might also experience intense thunderstorms with high winds, leading to isolated power outages, forecasters said.
“A brief isolated tornado cannot be ruled out either,” the agency said in the statement.
Thundershowers are expected to continue throughout Sunday, with an inch or two of rain possible, said NWS meteorologist Alan Dunham.
A “tropical, soupy air mass” is expected to park on the region for the next four days, bringing with it days of humidity and rain, she said.
The threat of scattered rain showers will probably continue through Friday as southerly wind flow keeps pumping in tropical conditions, Dunham said.
“It won’t be wet every single day, not a washout, just a chance [of rain] each day,” Buttrick said.
With dew points in the low- to mid-70s, the days are expected to be muggy this week, Dunham said. Temperatures will probably stay in the upper 70s to mid-80s during the same stretch.
“It’s not going to be as oppressive as it was that one week,” Buttrick said, pointing to the heat wave that started the month. “But it’s still going to be warm.”Globe correspondent Thomas Oide contributed to this report. Lucas Phillips can be reached at firstname.lastname@example.org.