OKLAHOMA CITY — As temperatures climbed into the 90s Sunday in Steele, N.D., a small window air conditioner in Paul and Betty Smokov's ranch home just couldn't keep up.
"It's 82 in the house," Betty Smokov said. "The heat is really oppressive and sticky."
That observation could be made anywhere in the central U.S. Heat advisories and warnings were in place in 17 states, from Texas to Michigan, as temperatures and humidity combined to make being outside uncomfortable for millions. One National Weather Service forecaster called the heat wave "unrelenting" and said sweaty residents shouldn't expect any relief soon: A so-called "heat dome" over the region isn't moving much.
"The trend is not our friend right now," said Daryl Williams, a forecaster in Norman.
In Oklahoma City, forecasters expected another day of 100-degree heat Sunday, which would be the 27th day this year the city has reached 100 or above. The city is on pace to break its record for such days — 50 set in 1980 — with triple-digit heat possible through September.
It's even worse in western Oklahoma, where temperatures at 110 or above have been common in recent weeks. In Enid, asphalt at a major intersection along U.S. Highway 412 buckled Saturday night from the intense heat.
Justin Tinder of Weatherford and his family visited the Oklahoma City Zoo on Sunday, arriving at 9 a.m.
"By noon, we were headed out," Tinder said. "It was too hot for us to stand much longer. We decided to check it in and go find some air conditioning."
In Chicago, city officials said a half-dozen cooling centers would remain open this week, as temperatures as high as 105 were forecast in Illinois.
Cooling centers also were open in Detroit to help residents who don't have air conditioning at home.