Storms knock out power to thousands amid heat wave

Scattered storms blew through the area Monday evening, downing trees and causing power outages after a day when temperatures surged past 90 degrees.

At 6 p.m. Monday, nearly 25,000 FirstEnergy customers were without electricity, mostly in northern Allegheny County, southwest Butler County and Beaver County. West Penn Power specifically was hardest hit in Westmoreland County, which accounted for 6,200 of 10,000 customers without power.

FirstEnergy spokesperson Todd Meyers said, however, that the longer the heat wave extends, the more demand and stress is placed on power infrastructure.

“People turn up their air conditioners, which is the largest part of electricity consumption,” Meyers said. “So you can have pieces of equipment which can fail, especially during a heat wave when you have day after day of temperatures in the 90s and high humidity.”

Duquesne Light reported more than 80,000 customers without power as of 9:45 p.m., in a swath stretching southeast from Ellwood City to Plum.

Meyers said unusually warm nights are also an issue for power suppliers.

“When it doesn’t cool off, that means the equipment is running nonstop,” he said. “Things like our substations are largely cooled by air, and if it stays warm at night but the demand continues, the equipment can get stressed.”

In the spring and fall of each year, Meyers said FirstEnergy work crews use digital inspections and thermal imaging to try and identify weak links in advance of the summer heat and the winter cold, when electricity usage peaks.

“Often times it’s deeper into a heat wave when you start to see impacts,” Meyers said. “We have people ready to respond to whatever comes our way later in the week.”

It’s been almost exactly three decades since the Pittsburgh area saw the kind of sustained high temperatures that are in store this week, according to National Weather Service meteorologists.

The last time it happened, in mid-June 1994, it was causing U.S. Open spectators to faint in Oakmont, NWS Meteorologist Shannon Hefferan said.

“A prolonged heat wave is what’s really the issue,” Hefferan said. “We always get some hot summer days, but not like this.”

The current NWS heat wave advisory is in effect until Friday, with highs in the 90s and — just as important — lows that remain in the 70s.

“That’s what happened in 1994,” Hefferan said. “We saw multiple days of temperatures in the 90s and night temperatures in the 70s. It should be closer to 60 degrees here at night for this time of year.”

Hefferan said the extended forecast has the potential to break records for both daytime highs and lows.

The National Weather Service is calling for an average high of 95 degrees across southwestern Pennsylvania through Wednesday.