Heat Expands for Center of the Nation; Severe Thunderstorms for Plains and Upper Midwest

Dangerous heat expands across the Desert Southwest, Plains, Mississippi Valley and Midwest. Critical fire weather for portions of the Intermountain West. Risk for severe thunderstorms and flash flooding across the Upper Midwest/Great Lakes, Ohio Valley, and portions of the mid-Atlantic. Active monsoonal moisture fuels thunderstorms over the Southwest. Hurricane Fausto in the Pacific, should weaken Read More >

Current conditions at

Tri-Township Airport (KSFY)

Lat: 42.05°NLon: 90.11°WElev: 614ft.

Mostly Cloudy

85°F

29°C

Humidity 77%
Wind Speed Calm
Barometer 29.90 in
Dewpoint 77°F (25°C)
Visibility 10.00 mi
Heat Index96°F (36°C)
Last update 26 Jul 12:35 pm CDT
Extended Forecast for

Lanark IL

Heat Advisory July 26, 12:41pm until July 27, 10:00pm
Click here for hazard details and duration
Heat Advisory
  •  
    Heat Advisory July 26, 12:41pm until July 27, 10:00pm

    NOW until 10:00pm Mon

    Heat Advisory

  • This Afternoon

    High: 89 °F

    Mostly Cloudy

  • Tonight

    Tonight: A 30 percent chance of showers and thunderstorms, mainly after 4am.  Mostly cloudy, with a low around 74. Southwest wind around 5 mph becoming southeast after midnight.

    Low: 74 °F

    Mostly Cloudy
    then Chance
    T-storms

  • Monday

    Monday: A 40 percent chance of showers and thunderstorms, mainly before 11am.  Mostly sunny, with a high near 91. Heat index values as high as 106. Southeast wind 5 to 15 mph becoming west in the afternoon. Winds could gust as high as 20 mph.

    High: 91 °F

    Chance
    T-storms then
    Mostly Sunny

  • Monday Night

    Monday Night: Partly cloudy, with a low around 69. West wind around 10 mph becoming northeast after midnight.

    Low: 69 °F

    Partly Cloudy

  • Tuesday

    Tuesday: Mostly sunny, with a high near 86.

    High: 86 °F

    Mostly Sunny

  • Tuesday Night

    Tuesday Night: Mostly clear, with a low around 62.

    Low: 62 °F

    Mostly Clear

  • Wednesday

    Wednesday: Sunny, with a high near 86.

    High: 86 °F

    Sunny

  • Wednesday Night

    Wednesday Night: Mostly clear, with a low around 62.

    Low: 62 °F

    Mostly Clear

Detailed Forecast

This Afternoon
Mostly cloudy, with a high near 89. Heat index values as high as 102. Southwest wind around 5 mph.
Tonight
A 30 percent chance of showers and thunderstorms, mainly after 4am. Mostly cloudy, with a low around 74. Southwest wind around 5 mph becoming southeast after midnight.
Monday
A 40 percent chance of showers and thunderstorms, mainly before 11am. Mostly sunny, with a high near 91. Heat index values as high as 106. Southeast wind 5 to 15 mph becoming west in the afternoon. Winds could gust as high as 20 mph.
Monday Night
Partly cloudy, with a low around 69. West wind around 10 mph becoming northeast after midnight.
Tuesday
Mostly sunny, with a high near 86.
Tuesday Night
Mostly clear, with a low around 62.
Wednesday
Sunny, with a high near 86.
Wednesday Night
Mostly clear, with a low around 62.
Thursday
Mostly sunny, with a high near 86.
Thursday Night
Partly cloudy, with a low around 65.
Friday
A 30 percent chance of showers. Partly sunny, with a high near 85.
Friday Night
Partly cloudy, with a low around 65.
Saturday
Mostly sunny, with a high near 86.
Basemap Options
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ABOUT THIS FORECAST

 
Point Forecast:
Lanark IL
 42.11°N 89.83°W (Elev. 883 ft)
12:31 pm CDT Jul 26, 2026
12pm CDT Jul 26, 2026-6pm CDT Aug 1, 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