A heat advisory that earlier this week had been restricted to eastern Arkansas will now cover more of the state, including Little Rock.
The National Weather Service said much of central and eastern Arkansas should see temperatures in the mid-90s that coupled with humidity will feel like heat in the 105 to 107 range.
The advisory runs from 1 p.m. to 6 p.m.
Highs across the state, even in places where there is no heat advisory, are expected to reach at least the low 90s.
The weather service said the conditions increase the risk for illnesses such as heat exhaustion and heat stroke. People are advised to drink plenty of fluids, stay out of the sun and in air conditioning, and check up on relatives and neighbors, the agency said in a statement.
The hot weather is expected to return Thursday, but some relief will likely develop Friday into Saturday, forecasters said.
"A break in the heat is expected this weekend as the weather pattern shifts, allowing a cold front to eventually move through the state," the weather service said in a statement. "Good chances of showers and thunderstorms will accompany the front with some strong or severe storms possible Friday afternoon and evening."