The National Weather Service in State College issued an extreme heat warning from noon Wednesday until 8 p.m. Friday for Mifflin County, Juniata County, and parts of central Pennsylvania. A heat advisory will follow from 8 p.m. Friday until 8 p.m. Saturday.

The warning calls for dangerously hot conditions, with the heat index reaching up to 108 degrees. The heat index measures how hot it feels when humidity is factored into the air temperature.

In Lewistown, Tuesday’s high was expected to reach the low 90s. Wednesday and Thursday are expected to be hotter, with highs near 99 degrees. Friday could reach 98 before afternoon thunderstorms may develop. Saturday is expected to remain hot and humid, with a high near 96 and another chance for storms. Conditions should ease slightly Sunday and Monday, with highs around 90 and 89.

Michael Colbert, a meteorologist with the National Weather Service in State College, said the heat will build through midweek and may peak when the heat index climbs above 105.

Sentinel photo by SAM BAUMGARDNER
Paisley Seiler, 10, of Lewistown, jumps off the diving board at Burnham Pool on Tuesday afternoon.

“It’ll be hot the whole rest of the week, really,” Colbert said.

Colbert said Tuesday’s heat index was expected to reach the upper 90s to near 100. Wednesday could be several degrees hotter, with the heat index topping 100 and possibly approaching 105. Thursday looks similar.

Friday remains less certain because afternoon thunderstorms could lower temperatures, Colbert said. If storms do not form early enough, Lewistown could again see a heat index above 105.

“The temperatures themselves also are quite impressive,” Colbert said. “Looks like we’ll see highs between 95 and 100 degrees.”

The heat will not end at sunset. Overnight lows are expected to stay in the low to mid-70s Wednesday through Saturday, giving homes without air conditioning little chance to cool.

Sentinel photo by SAM BAUMGARDNER
Konner Fisher, 7, of Lewistown, enjoys a cherry popsicle.

Justin Trego of Mifflin County Public Safety said older residents and people without air conditioning are among the biggest concerns.

Trego said he is most concerned about “our elderly population.”

Residents should avoid outdoor work during the hottest part of the day when possible, Trego said. Those who must work outside should take frequent breaks, cool down, and drink plenty of water.

“We encourage people to avoid working outside in the heat, if at all possible,” Trego said. “And if they do have to work outside, they should take multiple breaks, try to cool down, stay hydrated.”

Trego said Mifflin County does not have cooling stations open, but would set one up if the need develops. No additional staffing is planned at this time, though the county could activate more staff if necessary.

“We’re hoping that the community is prepared for the heat,” Trego said. “They’ve been warned about it coming.”

In Juniata County, Public Safety Director William Hummel said the danger is not limited to one group. Heat can affect older residents, people with breathing problems, people without air conditioning, outdoor workers, and anyone who pushes too hard.

“For the most part, people don’t prepare enough for extreme temperature days,” Hummel said.

Hummel urged residents to plan ahead, drink water, stay in the shade, and avoid overexertion. He said people should keep fluids cold if possible, have ice available, and avoid heavy, salty foods that can make heat harder on the body.

“Don’t overwork,” Hummel said. “Don’t push yourself too hard.”

Hummel said Juniata County residents who need relief from the heat may also turn to their local fire companies. He said those facilities can provide protection from the heat if a need develops.

Hummel said neighbors can also help during a heat wave, especially when someone nearby lives alone or lacks air conditioning.

“Unfortunately, you can’t watch everybody,” Hummel said. “That’s the problem we struggle with. It’s being aware of people and your neighbors, too, that helps.”

Colbert said people without air conditioning should look for cooler places, including libraries, other public spaces, or the home of a friend or relative.

“The goal is to get into a cooler location,” Colbert said.

The National Weather Service advises people to know the signs of heat exhaustion and heatstroke. Symptoms can include heavy sweating, weakness, dizziness, nausea, headache, and confusion. Heatstroke can cause loss of consciousness and a very high body temperature and requires immediate medical attention.

Outdoor workers should take frequent rest breaks in shade or air-conditioned spaces, according to the warning. Residents should also prepare for possible power outages because extended heat can increase demand on the electric grid.

The worst stretch appears to be Wednesday through Friday, with Thursday and Friday likely to bring the strongest mix of high temperatures and humidity. Saturday should be slightly cooler, but still dangerous for people without a way to cool down.