The heat wave continues in Colorado Wednesday, and an afternoon storm system could bring heavy rain, golf ball-sized hail and strong winds to the Front Range and Eastern Plains, according to the National Weather Service.

Overnight Tuesday in the Denver area, temperatures only dropped to a low of 68 degrees — the warmest daily low temperature on record for June 25, according to NWS records. The previous record for warmest low temperature was 67 degrees, set in 1990.

Temperatures hit 100 degrees in the Denver area Tuesday, marking the hottest day for the city so far this year, NWS meteorologists said.

The city is on a cooling trend, with temperatures slowly decreasing throughout the rest of the week, forecasters said. The trend is set to end Saturday with a high of 85 degrees before the city starts heating back up, reaching high-90s Sunday and Monday.

With the hot weather, the Colorado Department of Public Health and Environment issued an Ozone Action Day Alert for the Front Range Urban Corridor, including Douglas, Jefferson, Denver, Arapahoe, Adams, Broomfield, Boulder, Larimer and Weld counties.

Increased ozone concentrations and hot, stagnant weather could create unhealthy air quality conditions Tuesday afternoon and early evening, the ozone advisory stated.

State officials said people in the affected counties should limit driving gas and diesel-powered vehicles until 4 p.m. Tuesday. The highest ozone concentrations are expected to be in and near the Denver metro area.

Denver will see a high around 92 degrees Wednesday with a 40% chance of rain showers and thunderstorms after 3 p.m., forecasters said.

Some of the afternoon storms could bring heavy rain and hail to the metro area, but the largest threat of severe weather is forecasted to hit the plains east of Greeley.

Severe storms could bring golf ball-sized hail, up to 70 mph winds, flooding and the threat of a tornado touchdown to the Eastern Plains between 3 p.m. and 9 p.m. Wednesday, NWS forecasters said.

Non-severe storms could still bring heavy rain and up to 50 mph wind gusts to the Urban Corridor and western Colorado, forecasters said.

Wednesday’s afternoon and evening thunderstorms will bring heavy rain and possible flash flooding, especially over alpine burn scars, NWS forecasters said in a hazardous weather outlook.

In areas where fire burns hot or long enough — including burn scars left by the Cameron Peak fire in Jackson and Larimer counties, the East Troublesome in Grand and Larimer counties and the Williams Fork fire in Grand County — the soil develops a water-repellant layer that reacts like rain on pavement, weather officials said.

Rainfall that would normally be absorbed by the forest canopy and loose tree litter on the ground instead runs off, starting flash floods during periods of heavy rain.

“If you can look uphill from where you are and see a burnt-out area, you are at risk,” NWS meteorologists said.

Thunderstorms will continue Thursday afternoon and evening but are expected to dry out before the weekend, forecasters said in the hazardous weather outlook.

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