The Washington area is expecting a 10th straight day of temperatures above 90 degrees today after record-breaking heat that exceeded 100 degrees yesterday and prompted the electric-power grid operator for the Mid-Atlantic region to urge customers to conserve electricity.
Record high temperatures were set at all three major local airports in the afternoon yesterday, according to the National Weather Service.
At the top of the chart, Ronald Reagan Washington National Airport recorded a high of 102 degrees, which topped the 101-degree record set in 1930.
Temperatures at Baltimore-Washington International Thurgood Marshall Airport reached 102 degrees, beating the record of 99 degrees set in 1980.
And, Washington Dulles International Airport recorded 101 degrees, which beat the 1980 record of 98 degrees.
Forecasters say lower temperatures are on the way.
“We’re probably not going to break another record,” said Jim Decarufel, a meteorologist at the National Weather Service in Sterling, Va. “We’re looking for a frontal system to move into the area.”
The high temperatures today and tomorrow are expected to be in the mid-90s, and forecasters said a cold front moving into the area from Canada should bring temperatures down to the high 80s by the weekend.
Mr. Decarufel said storms also could bring some relief to parts of Western Maryland last night but probably will not reach the D.C. area.
“It’s not looking good right now, but there’s always hope,” he said about the 20 percent chance of showers tonight.
Meanwhile, PJM Interconnection, the electric-grid operator for 51 million people between the District and New York, said the surge in electricity demand for air conditioning yesterday forced it to cut voltage by 5 percent across the board.
The move is aimed at conserving dwindling power supplies and ensuring the area has enough electricity to meet “extremely high” demand during the heat wave. The company said most home and business appliances can operate with a 5 percent reduction in voltage, and most consumers won’t notice it.
The voltage reduction affects several services territories, including those of Potomac Electric Power Co., Baltimore Gas & Electric Co. (BGE) and Delmarva Power.
PJM said electrical equipment generally is designed to operate at plus or minus 10 percent of normal 120-volt current.
To ensure that the D.C. area gets through the heat wave without an interruption of electricity, PJM also is asking consumers to conserve where they can. It has already asked businesses, which are the utilities’ largest customers, to cut back and use backup facilities when possible.
BGE officials said the central Maryland region set a record Tuesday for electricity use this year with an hourly usage peak of 6,739 megawatts. That beat this summer’s previous record of 6,629 megawatts set June 27.
Officials said typical summer usage peaks at about 5,500 megawatts. The current record of nearly 7,200 megawatts was set last August.
The sweltering heat and humidity prompted the weather service to post a heat advisory until 8 p.m. yesterday. People were advised to stay out of the sun, drink plenty of fluids and check on elderly neighbors.
Emergency crews got more calls than usual yesterday, but it was not clear how many were heat-related. Paramedics took to the hospital a 26-year-old woman who fainted while touring the White House yesterday. Her injuries were not considered serious, authorities said.
Local construction companies said the heat has led them to make adjustments to keep workers productive.
“Today, we wanted to get everyone off the roof by noon,” said Tim Alvarez, a project manager at Function Enterprises Inc., a commercial roofing company in Springfield. “Most of our guys get used to the heat, but it is way too hot now, and it’s beginning to slow down production.”
Some companies are starting work earlier in the morning or sending workers home early.
“Most of our subcontractors are sending their employees home early today so they can get out of the heat,” said Rich Pfau, safety director at Donohoe Construction Co., a general contractor in the District. “Our workers normally start at seven in the morning, but today they started at six, when it’s cooler out.”
Even some four-legged workers got a break yesterday.
The horses usually roaming the streets of Colonial Williamsburg were taken off the streets, and no carriage rides were given.
Officials in the District closed the vehicle-inspection station in Southwest at 1 p.m. and reminded residents to take advantage of the city’s four cooling centers. They are at One Judiciary Square Northwest, the Reeves Center at 14th and U streets Northwest, 25 M St. SW and 3720 Martin Luther King Ave. SE.
Some local transit systems such as Metro and the Fairfax Connector also offered free rides to certain passengers, such as senior citizens.
In the afternoon, Metro told riders to prepare for delays as trains were operated manually at 45 mph on tracks aboveground as a safety precaution because excessive heat could cause tracks to bend, officials said. The trains typically run at a top speed of 59 mph.
The delays worsened during the evening rush when officials shut down three stations — Dupont Circle, Woodley Park and Cleveland Park — because of a suspicious package. Hundreds of passengers had to wait outside in the heat for shuttle buses.
The stations reopened at about 5 p.m. after the package was determined to be no threat.
c Bryce Baschuk and Patrice Hill contributed to this article, which is based in part on wire service reports.
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