Oppressive. Dangerous. Those warnings, rarely voiced by government forecasters in our region, sum up the tropical steam bath Berkshire residents and visitors will endure this weekend.
The core of the sizzling dome of heat and humidity will be over the Northeast on Saturday and Sunday, according to the National Weather Service in Albany, N.Y.
Berkshire County and Southern Vermont are targets of a rarely issued two-day heat advisory, in effect from noon Saturday until 8 p.m. Sunday, while a higher-level excessive heat warning is in effect through Sunday evening in the rest of Massachusetts — except for the ocean-cooled Cape and Islands — as well as New York’s Capital District and Hudson Valley.
Factoring in the high humidity, with air temperatures approaching the mid-90s on Saturday, it will feel like at least 100 even in the normally cooler higher elevations of the Berkshire Hills and the Green Mountains of Vermont. The dew point, a measure of moisture in the air, should be in the low 70s, well over the 60-degree threshold when most people begin feeling uncomfortable.
Sunday’s high should reach 90, and cloud cover and a 50-50 chance of thunderstorms Monday might hold temperatures to the upper 70s.
At Tanglewood, no performance has been canceled due to extreme heat during the past 20 years, though information is lacking about earlier years, Boston Symphony Orchestra officials told The Eagle.
For this weekend, informal garb is the recommendation for orchestra musicians, and plenty of bottled water will be on hand. Onstage, fans are used only as a last resort because they can interfere with the live or broadcast audio experience.
“We will be keeping a careful eye on the situation and will implement the fan system at the first sign they are needed,” the BSO management stated by email.
“The BSO will also be on high alert with medical personnel on hand to help any musician or patron who may become affected by the heat,” the statement added. “We encourage everyone to dress accordingly for extreme high temperatures and to stay hydrated.”
Power companies have braced for a surge in energy consumption as nearly 100 million Americans live where a daily record-high temperature could be set Saturday, when the heat wave peaks, AccuWeather.com Senior Meteorologist Alex Sosnowski predicted in an online post.
How do you spell relief? Monday, as a cold front passes through, followed by refreshing air for most of next week.
The official definition of a heat wave is three consecutive days of 90 or above, according to Christina Speciale, meteorologist at the National Weather Service in Albany. It’s quite rare in higher-terrain areas like the Berkshires and Southern Vermont, she noted.
“We haven’t gotten rid of the tropical moisture brought in on Wednesday from the remnants of Tropical Storm Barry,” Speciale said. “Very high humidity, combined with heat moving east from the Midwest, is setting us up for a very uncomfortable weekend, with dangerous conditions if you’re outside” or don’t have air-conditioning.
This weekend, keep away from beer when you’re outdoors, she advised, since “alcohol and heat don’t mix.”
Cooling centers in the Berkshires open this weekend include senior centers in Pittsfield and Adams. Pittsfield residents also can cool off at the Berkshire Athenaeum on Saturday, and on Sunday at The Salvation Army.
In Great Barrington, the Berkshire South Regional Community Center off Stockbridge Road will be available as a cooling center through Sunday, during regular hours.
Friday’s high topped out at 89 at Pittsfield Municipal Airport as of 5 p.m., while North Adams had a high of 87 at Harriman-and-West Airport.
In its heat advisory, the weather service cautioned that “heat illnesses are likely for those spending prolonged periods of time outdoors or in non-air conditioned locations. Prolonged heat is most dangerous for young children and the elderly.”
Common-sense precautions include confining strenuous outdoor activities to early morning or late evening, being aware of heat exhaustion and stroke symptoms, staying hydrated and dressing not to impress but to be well-ventilated.
And don’t even think about leaving your animal companion in a car, even for a quick stop at a store: Vehicle temperatures can reach lethal levels in minutes.
If thunderstorms develop over the weekend, lead forecaster Neil Stuart at the National Weather Service suggests keeping an eye out for damaging winds and potential power disruptions.
The midsummer scorcher is on track to melt the high-temperature record for July 20: 91 degrees, set in 1991. The July 21 high of 93, recorded in 2011, also is a wipeout candidate, while a slight improvement Monday should preserve the 93-degree record for July 22, also set in 2011.
So far this month, there have been above-average temperatures on 18 out of 19 days, a contrast to the cooler and frequently rainy days of June. National Weather Service records at Pittsfield Municipal Airport have been kept for 80 years.
Last summer, the only heat wave was a four-day stretch in the low 90s at the beginning of July, preceded by a 90-degree high June 18 and two record highs of 90 — on Aug. 6 and Aug. 29. But in summer 2017, it never hit 90.
Before last summer, the only heat waves lasting three days or more at the Pittsfield airport were in July 2010 and from late August into early September 1953.
The highest temperature for any date since 1938 has been 95 on three occasions — July 6, 2010, July 3, 1966, and Sept. 2, 1953.