Last Searing Scorcher: St. Louis Swelters in 109-Degree Heat Before

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St. Louis is headed into one more dangerous summer heat day Sunday, with partly sunny skies, a high near 94 degrees and heat index values as high as 109. A chance of showers and thunderstorms could bring brief heavy rain and gusty weather before cooler air arrives Monday.

Extreme Heat Warning Runs Through Sunday Evening

Early Sunday conditions were partly cloudy with temperatures near 79 degrees, while northwest winds were moving at roughly 3 to 8 mph. The National Weather Service has an Extreme Heat Warning in effect through 9 p.m., citing heat index values from 105 to 110 degrees across the region.

Residents should limit time outdoors during the hottest part of the day, drink plenty of fluids and use air conditioning when possible. The weather service also recommends checking on relatives and neighbors who may be especially vulnerable to extreme heat.

Storms Could Bring Heavy Rain And Gusty Winds

Showers and thunderstorms are possible Sunday morning, with pockets of heavy rain more likely north of Interstate 70 and localized flooding possible where storms repeat over the same areas. Another round of scattered storms could develop late Sunday afternoon and evening along and south of the advancing front.

The strongest storms could produce damaging wind gusts, locally heavy rain and a brief weak tornado, although the exact location remains uncertain. Anyone with outdoor plans should keep an eye on changing conditions and move indoors promptly if storms approach.

Monday Brings A Noticeable Break

Storm activity should move out overnight, setting up a much more comfortable Monday. The forecast calls for mostly sunny skies, a high near 86 degrees, a low around 69 and light north winds.

Tuesday will turn warmer again, reaching about 91 degrees under sunny skies, but the bigger weather change arrives Tuesday night into Wednesday. Thunderstorm chances rise to around 50% during that period, with additional showers and storms possible through Thursday before mostly sunny, seasonable conditions return Friday and Saturday.