Sunny and dry conditions with near record temperatures across metro Denver on Thursday will reduce air quality and raise fire risks, according to the National Weather Service.

The heat will persist through the weekend and, in the high mountains and valleys, winds will intensify in the afternoons, gusting at speeds up to 25 miles per hour, weather service forecasters said.

State health officials issued an air quality alert for Colorado Front Range cities along Interstate 25, effective through 4 p.m., warning that pollution combined with heat may raise the concentrations of ground-level ozone to unhealthy levels.

Temperatures around Denver on Thursday afternoon will hit 97 degrees, decreasing to 63 degrees at night, forecasters said. On Friday, the high temperature is expected to be 95 degrees.

Colorado Department of Public Health and the Environment officials requested that residents reduce driving in gas and diesel vehicles as pollution reaches levels considered harmful for children, the elderly, and people with respiratory ailments such as asthma. Additional air pollution in Denver and western portions of the northern Front Range “may directly worsen air quality,” officials said, warning that ozone levels are expected to be highest in areas near Golden, Boulder, and Fort Collins.

While isolated thunderstorms in Colorado’s mountains may bring rain, wind blowing through dry valleys is expected to create conditions favoring fires, particularly in Jackson and Grand counties, meteorologists said. Fire risks also are increasing across the high plains of eastern Colorado with temperatures widely exceeding 95 degrees.