Deloris Knight of Detroit, Mich., sits on her front porch, Wednesday, July 17, 2019, as she prepares for the heat wave that will descend upon Detroit and a wide section of the Midwest. Knight said she will keep the heat out of her Eastside Detroit home by keeping her doors and curtains closed while running the small window air conditioner in the living room. "We have a couple of big fans. We have ceiling fans," Knight, 63, said while enjoying Wednesday's more comfortable 80-plus degree weather from her front porch. (AP Photo Corey Williams)
Deloris Knight of Detroit, Mich., sits on her front porch, Wednesday, July 17, 2019, as she prepares for the heat wave that will descend upon Detroit and a wide section of the Midwest. Knight said she will keep the heat out of her Eastside Detroit home by keeping her doors and curtains closed while running the small window air conditioner in the living room. "We have a couple of big fans. We have ceiling fans," Knight, 63, said while enjoying Wednesday's more comfortable 80-plus degree weather from her front porch. (AP Photo Corey Williams) Credit: Corey Williams

The heat wave that has been roasting much of the U.S. in recent days is just getting warmed up, with temperatures expected to soar to dangerous levels through the weekend.

Communities are preparing by offering buildings as cooling centers and asking residents to check in on relatives and neighbors. Officials also are concerned about smog, which is exacerbated by the heat and makes it more difficult for certain people to breathe, including the very young, the elderly and people with asthma or lung diseases.

More than 100 local heat records are expected to fall Saturday, according to the National Weather Service. Most wonโ€™t be record-daily highs but record-high nighttime lows, and that lack of cooling can be dangerous, meteorologists say. Temperatures in parts of the East wonโ€™t drop below the mid- to upper-70s or even 80 degrees at night, he said.

The heat wave will likely be โ€œshort and searing,โ€ said Greg Carbin, forecast branch chief for the weather serviceโ€™s Weather Prediction Center.

A high pressure system stretching from coast-to-coast is keeping the heat turned on. The heat and humidity are made to feel worse by the large amount of moisture in the air coming from the Gulf of Mexico, much of it left over from Hurricane Barry.

The heat index, which is what the temperature feels like, should hit 110 in Washington, D.C., on Saturday and 109 in Chicago and Detroit on Friday, said Jeff Masters, meteorology director of Weather Underground. Wednesday marked Washingtonโ€™s seventh straight day with temperatures of at least 90 degrees, and that streak was expected to last for another five days.

An experimental weather service forecast projects that nearly 100 local records will be broken Thursday and Friday in Texas, Oklahoma, parts of the Midwest and a large swath of the East Coast. On Saturday, 101 records could fall in an area stretching from Texas to Iowa and east to Maine and Florida, according to projections.

Deloris Knight said she will keep the heat out of her eastside Detroit home by keeping her doors and curtains closed while running the small window air conditioner in her living room.

โ€œWe have a couple of big fans. We have ceiling fans,โ€ Knight, 63, said Wednesday while enjoying temperatures in the mid-80s from her front porch. โ€œI keep lemonade and gallons of frozen water in the refrigerator. At night, weโ€™re in the house.โ€