Thunderstorms and Heavy Rainfall in the Plains; Hazardous Heat in the South and Southeast

Severe thunderstorms will be possible across the northern/central Plains through Tuesday afternoon and from the central Plains to the Mid-Mississippi Valley Tuesday evening through Wednesday morning. Storms may produce large hail and damaging wind gusts, and heavy rainfall may lead to scattered instances of flash flooding. Meanwhile, hazardous heat persists across the South and Southeast. Read More >

Current conditions at

St. Louis Lambert International Airport (KSTL)

Lat: 38.75°NLon: 90.37°WElev: 604ft.

A Few Clouds

70°F

21°C

Humidity 87%
Wind Speed Calm
Barometer 30.06 in (1017.0 mb)
Dewpoint 66°F (19°C)
Visibility 10.00 mi
Last update 18 Aug 2:51 am CDT
Extended Forecast for

Frontenac MO

  • Overnight

    Overnight: Clear, with a low around 67. Calm wind.

    Low: 67 °F

    Clear

  • Tuesday

    Tuesday: Sunny, with a high near 89. Calm wind becoming south around 5 mph.

    High: 89 °F

    Sunny

  • Tuesday Night

    Tuesday Night: Isolated showers, then showers and thunderstorms likely after 3am.  Increasing clouds, with a low around 72. Southeast wind around 6 mph becoming light and variable  after midnight.  Chance of precipitation is 60%.

    Low: 72 °F

    Mostly Clear
    then T-storms
    Likely

  • Wednesday

    Wednesday: Showers and thunderstorms, mainly before 9am.  High near 84. South wind 5 to 7 mph becoming north in the afternoon.  Chance of precipitation is 80%.

    High: 84 °F

    T-storms then
    Scattered
    T-storms

  • Wednesday Night

    Wednesday Night: A 50 percent chance of showers and thunderstorms.  Mostly cloudy, with a low around 69. Northeast wind around 5 mph becoming calm  in the evening.

    Low: 69 °F

    Chance
    Showers

  • Thursday

    Thursday: Mostly sunny, with a high near 84.

    High: 84 °F

    Mostly Sunny

  • Thursday Night

    Thursday Night: Mostly clear, with a low around 67.

    Low: 67 °F

    Mostly Clear

  • Friday

    Friday: Sunny, with a high near 87.

    High: 87 °F

    Sunny

  • Friday Night

    Friday Night: Mostly clear, with a low around 69.

    Low: 69 °F

    Mostly Clear

Detailed Forecast

Overnight
Clear, with a low around 67. Calm wind.
Tuesday
Sunny, with a high near 89. Calm wind becoming south around 5 mph.
Tuesday Night
Isolated showers, then showers and thunderstorms likely after 3am. Increasing clouds, with a low around 72. Southeast wind around 6 mph becoming light and variable after midnight. Chance of precipitation is 60%.
Wednesday
Showers and thunderstorms, mainly before 9am. High near 84. South wind 5 to 7 mph becoming north in the afternoon. Chance of precipitation is 80%.
Wednesday Night
A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 69. Northeast wind around 5 mph becoming calm in the evening.
Thursday
Mostly sunny, with a high near 84.
Thursday Night
Mostly clear, with a low around 67.
Friday
Sunny, with a high near 87.
Friday Night
Mostly clear, with a low around 69.
Saturday
Sunny, with a high near 88.
Saturday Night
Mostly clear, with a low around 67.
Sunday
Mostly sunny, with a high near 85.
Sunday Night
A 20 percent chance of showers. Partly cloudy, with a low around 68.
Monday
A 20 percent chance of showers. Mostly sunny, with a high near 87.
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ABOUT THIS FORECAST

 
Point Forecast:
Frontenac MO
 38.65°N 90.4°W (Elev. 558 ft)
3:25 am CDT Aug 18, 2026
3am CDT Aug 18, 2026-6pm CDT Aug 24, 2026
 
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Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database