The Berkshires and southern Vermont will be under a heat dome for the next few days as a midsummer high pressure system that has set records in the Midwest moves toward New England.
It won't be the region's first hot spell of the season by any means. But it will be the longest and most intense, with temperatures pushing toward 90, with Sunday likely to be the worst day of the weekend for heat and tropical humidity.
"It's just a large area of high pressure which has been centered over the Plains states," according to AccuWeather forecaster Brian Edwards. "It's basically a big dome of hot air."
The near-drought that has gripped western New England in recent weeks is likely to continue despite potentially severe thunderstorms that may pop up late Friday, with potential damaging winds and large hail, and again on Monday.
Berkshire County and Bennington County in Vermont are classified as "abnormally dry," the lowest level on the drought scale, according to the U.S. Department of Agriculture's latest weekly Drought Monitor released Thursday morning.
So far this year, total precipitation (rainfall and melted snow) has run 24 percent below normal, as recorded by the National Weather Service at Pittsfield Municipal Airport. The normal total through July 20 is 24.68 inches; the actual amount was 18.73, reflecting not only sparse rainfall since March and one of the lightest snowfall seasons on record.
Stream and river flows in the region are as much as 80 percent below normal. Lake levels also have dropped.
Most of central and northeastern Massachusetts are worse off, ranking in the moderate to severe drought categories, the USDA reported.
"Impacts are far reaching across the region as many farmers are using irrigation methods as the dry conditions hindered growth and stressed crops," the agency stated.
More than 120 towns across Massachusetts have adopted various mandatory water restrictions, including Hinsdale and Williamstown.
There's no immediate sign of a beneficial, soaking rainfall, forecasters said. But AccuWeather predicts a wetter than normal pattern, with frequent showers and thunderstorms, could appear between July 30 and Aug. 3.
As for the steamy heat and humidity, limited relief is in sight on Tuesday, but it's unlikely to approach the comfort levels of the past couple of days in western New England.
"While the heat will throttle back a bit next week, temperatures and humidity levels will probably not come down like earlier this summer," said Paul Pastelok, a long-range meteorologist for AccuWeather. "We are entering a long stretch of typical hot and humid weather that will live up to the phrase 'dog days of summer.' "
Contact Clarence Fanto at 413-637-2551.
Steamy days ahead ...
Friday: Partly sunny, possible severe thunderstorms. High: 88. Low: 68.
Saturday: Mostly sunny, hot, humid. High: 87. Low: 63.
Sunday: Partly cloudy, hot. High: 89. Overnight low: 64.
Monday: Cloudy, hot, possible thundershowers. High: 86. Low: 66.