The heat wave that has set in across the Triangle tied an all-time record for the area again Saturday at 105 degrees. It's expected to go down as one of the hottest streaks ever recorded in the region, weather data show.

It’s also potentially deadly because temperatures are not expected to significantly cool off in the evenings. Weather officials say heat is the No. 1 weather-related killer in the United States each year, causing hundreds of deaths.

The National Weather Service has issued a rare “heat warning,” urging people to take steps to stay out of the sun, remain cool and watch for heat exhaustion.

The temperature today hit 105 degrees at 4 p.m. at Raleigh-Durham International Airport, tying the all-time record for the highest temperature recorded at the airport. It also hit 105 degrees on Friday. Today's record temperature eclipsed the previous June 30 record of 102 degrees set in 1945 and tied in 1959.

The weather service also said that conditions similar to those that brought strong winds Friday night was forming around Illinois and could bring a repeat performance, though it was too soon to determine that.

Computer models did not predict the conditions that developed Friday night, so they “are all suspect concerning storm activity this afternoon. Current thinking is that a few storms may form over the central part of the state and move into coastal plains later this afternoon. ... Any storm that does form has the potential to become severe,” forecasters said.

Gail Hartsfield, a forecaster with the weather service in Raleigh, said this isn’t just usual North Carolina summer heat. A heat warning means something much more serious.

“We don’t do it lightly,” she said of the warning. “We are looking at days and days of heat compounded by not cooling off in the evenings.”

Hartfield said studies of deaths and illnesses in heat waves show that when low temperatures only drop to around 80 degrees at night, it often leads to increased heat stroke, heart attacks and other ailments. She called heat a “silent killer” because it triggers a range of ailments that people may not realize were caused by the heat.

“You really see injuries and mortalities when you do not cool off at night,” she said. “The body needs to cool. This kind of heat exacerbates illness.”

Daily low temperatures are expected to be 79 degrees or 80 degrees through at least Tuesday.

Highs should exceed 100 degrees through Monday.

Raleigh-Durham International Airport’s high temperature of 105 degrees Friday and Saturday tied the highest temperature ever recorded for the airport on any day. The Triangle last saw 105 on Aug. 21, 2007.

Effects of the hot weather are being felt across the Triangle.

Westbound lanes of Interstate 440 at Jones Franklin Road were closed Friday afternoon after the pavement buckled from the heat. No accidents were reported.

The Capital Area Soccer League’s Friendship Cup youth soccer tournament scheduled for today was postponed until next weekend. Edenton Street United Methodist Church moved the closing ceremony of its “Camp Shalom” youth camp on Friday afternoon from Umstead Park to the church fellowship hall. The North Carolina Symphony’s “Romeo & Juliet” concert at Koka Booth Amphitheatre in Cary was delayed from 7:30 p.m. to 8:30 p.m. Saturday in hopes that it will be a bit cooler.

Falling records

More heat records are expected to fall in coming days.

Records show that there have been only three previous stretches when temperatures were at or above 102 degrees for three days in a row – in July 1952, August 2007 and last July.

The 1952 heat wave was especially brutal, with an 11-day stretch in July of withering heat that included two 104-degree days and the record of 105 on July 23, after a June that also saw two 104-degree days.

On the record-breaking day, The News & Observer reported on faintings among state workers and measured the temperature at 102 degrees in one state office. “Every fan was blowing,” the article said, “but the heat would not be beat.”

Last year’s streak of five 100-degree days, ending on July 24, is the longest streak of 100-degree days on record.

Staff writer Ron Gallagher and the Associated Press contributed to this report.

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