Excessive Rainfall Potential for the Southeast; Heat Expands for Center of the Nation; Critical Fire Weather for Pacific Northwest

Flash flooding threatens areas from the Tennessee Valley to the Carolinas as storms repeat along a stalled front. Monsoonal storms may trigger flooding in the Southwest. Dangerous heat expands across the Desert Southwest, Plains, mid-Mississippi Valley and Southern Tier. Critical fire weather for interior Pacific Northwest. Cooler, drier air brings brief relief to the Great Lakes and Northeast. Read More >

Current conditions at

Tri-Township Airport (KSFY)

Lat: 42.05°NLon: 90.11°WElev: 614ft.

Fog/Mist

73°F

23°C

Humidity 95%
Wind Speed SE 3 mph
Barometer 29.94 in
Dewpoint 72°F (22°C)
Visibility 5.00 mi
Last update 26 Jul 12:55 am CDT
Extended Forecast for

Lanark IL

Extreme Heat Watch July 26, 09:00pm until July 27, 10:00pm
Heat Advisory July 26, 11:00am until July 26, 09:00pm
Click here for hazard details and duration
Extreme Heat Watch
Heat Advisory
  • Overnight

    Overnight: A 30 percent chance of showers and thunderstorms, mainly after 5am.  Mostly cloudy, with a low around 69. South wind around 5 mph becoming calm.

    Low: 69 °F

    Chance
    Showers

  • Sunday

    Sunday: A 30 percent chance of showers and thunderstorms, mainly before 7am.  Mostly cloudy, then gradually becoming sunny, with a high near 90. Heat index values as high as 102. South wind 5 to 10 mph.

    High: 90 °F

    Chance
    Showers then
    Mostly Sunny

  • Sunday Night

    Sunday Night: A 30 percent chance of showers and thunderstorms, mainly between 4am and 5am.  Partly cloudy, with a low around 75. Southwest wind around 5 mph becoming northeast after midnight.

    Low: 75 °F

    Partly Cloudy
    then Chance
    Showers

  • Monday

    Monday: A 50 percent chance of showers and thunderstorms, mainly before 9am.  Mostly sunny, with a high near 94. Heat index values as high as 109. South wind 5 to 15 mph, with gusts as high as 20 mph.

    High: 94 °F

    Chance
    Showers then
    Sunny

  • Monday Night

    Monday Night: Mostly clear, with a low around 70.

    Low: 70 °F

    Mostly Clear

  • 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

Overnight
A 30 percent chance of showers and thunderstorms, mainly after 5am. Mostly cloudy, with a low around 69. South wind around 5 mph becoming calm.
Sunday
A 30 percent chance of showers and thunderstorms, mainly before 7am. Mostly cloudy, then gradually becoming sunny, with a high near 90. Heat index values as high as 102. South wind 5 to 10 mph.
Sunday Night
A 30 percent chance of showers and thunderstorms, mainly between 4am and 5am. Partly cloudy, with a low around 75. Southwest wind around 5 mph becoming northeast after midnight.
Monday
A 50 percent chance of showers and thunderstorms, mainly before 9am. Mostly sunny, with a high near 94. Heat index values as high as 109. South wind 5 to 15 mph, with gusts as high as 20 mph.
Monday Night
Mostly clear, with a low around 70.
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)
1:26 am CDT Jul 26, 2026
1am 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