If Berkshire County residents think they've entered a tropical rain forest, they're close to the mark.
An extremely sultry air mass has engulfed the region, with frequent downpours and thunderstorms expected for the next four or five days, according to the National Weather Service.
Temperatures are expected to approach 90 on Thursday, while intense storms could drop three to four inches of total rainfall by next Monday, when a drier, cooler air mass is slated to arrive to eject the tropical plume of hot air from the region.
Channel 13 and WAMC meteorologist Paul Caiano likens the deep dive into a soggy, steamy cauldron of heat, humidity and rain to a steam bath.
The only silver lining is that the area could emerge from the near-drought conditions that have persisted for the past seven months.
Over the next four days, AccuWeather.com is predicting at least 3 inches of rain in Pittsfield and the rest of central and south Berkshire County, about 2 inches in North Adams and neighboring towns,.
"We've been lucky so far this summer compared to the rest of the country," said Joe Kravitz, atmospheric scientist based at Berkshire Community College. He noted that until now, the jet stream has been strong enough and far enough south to block tropical air from reaching western New England except for a day or two at a time.
But now, the jet stream "wall" has weakened has shifted into northern New England, he pointed out, opening the floodgates for an invasion of tropical air courtesy of the "Bermuda High" heat dome that pumps the hottest summer weather into the Northeast.
While Thursday looks "incredibly muggy," Kravitz said, the onslaught of intense thunderstorms with heavy rain is most likely on Friday and the rest of the weekend.
The region will be engulfed by "incredibly unstable air," he said.
Breaks of sunshine will cause thunderstorms "to explode, but the question is where, when and how much." The main threat is from storms that stall over a specific area, causing torrential downpours.
The dividing line between the sultry air and a drier air mass moved north of the Berkshires on Wednesday morning, then stalled and shows no sign of moving back south as a cold front until late Sunday or Monday morning, when gradual relief should arrive.
"For people who don't like hot humid air, Thursday and Friday will be pretty unbearable," Kravitz warned.
On Saturday and Sunday, clouds and the expected thundershowers should hold down temperatures a bit. By Tuesday and Wednesday, look for clear skies with comfortable temperatures and humidity.
Contact Clarence Fanto at 413-637-2551.
Here's the National Weather Service outlook for the next seven days:
Thursday: Mostly sunny, high near 90, possible thunderstorms at night could produce heavy rain.
Friday: Mostly cloudy, showers and possible thunderstorms after 2 p.m., some with heavy rain. High around 87. More thundershowers at night.
Saturday: Showers likely, mainly after 2 p.m., high near 86, more showers in the evening.
Sunday: Showers and thunderstorms likely, mainly after 2 p.m., with potentially heavy rain. High near 80.
Monday: 50-50 chance of showers, thunderstorms, high near 75.
Tuesday: Partly sunny, high in mid-70s, scattered showers, thunderstorms, 30 percent chance.
Wednesday: Mostly sunny, low humidity high in the upper 70s.