National Oceanic and Atmospheric Administration National Weather Service United States Department of Commerce

Erin Strengthens to a Hurricane; Heavy Rainfall Possible in Puerto Rico and the Virgin Islands, the Upper Midwest, South Texas

Hurricane Erin may bring isolated flash and urban flooding, landslides or mudslides, and possible tropical storm conditions to Puerto Rico and the U.S. Virgin Islands this weekend. Scattered thunderstorms and heavy rainfall may bring areas of flooding this weekend over the Upper Midwest. A tropical disturbance will bring locally heavy rain and mainly urban flash flooding to far southern Texas. Read More >

Hazardous Weather Conditions

Current conditions at

Sterling Rockfalls (KSQI)

Lat: 41.74°NLon: 89.67°WElev: 643ft.

Fair

88°F

31°C

Humidity 57%
Wind Speed Vrbl 3 mph
Barometer 30.08 in (1018.0 mb)
Dewpoint 71°F (22°C)
Visibility 10.00 mi
Heat Index94°F (34°C)
Last update 15 Aug 1:56 pm CDT
Extended Forecast for

Lanark IL

Severe T-storm Watch until August 15, 07:00pm
Click here for hazard details and duration
Severe T-storm Watch
  •  
    Severe T-storm Watch until August 15, 07:00pm

    NOW until 7:00pm Fri

    Severe T-storm Watch

  • This Afternoon

    High: 88 °F

    Sunny

  • Tonight

    Tonight: Showers and thunderstorms likely, mainly before 11pm. Partly cloudy, with a low around 73. Calm wind becoming southeast around 5 mph after midnight. Chance of precipitation is 70%.

    Low: 73 °F

    T-storms
    Likely then
    Chance
    T-storms

  • Saturday

    Saturday: A 20 percent chance of showers and thunderstorms before 11am. Mostly sunny, with a high near 92. South wind 5 to 10 mph.

    High: 92 °F

    Slight Chance
    T-storms then
    Mostly Sunny

  • Saturday Night

    Saturday Night: A slight chance of showers and thunderstorms between 1am and 4am, then a slight chance of showers after 4am. Partly cloudy, with a low around 72. South wind around 5 mph becoming southeast after midnight. Chance of precipitation is 20%.

    Low: 72 °F

    Partly Cloudy
    then Slight
    Chance
    T-storms

  • Sunday

    Sunday: Mostly sunny, with a high near 90.

    High: 90 °F

    Mostly Sunny

  • Sunday Night

    Sunday Night: Partly cloudy, with a low around 70.

    Low: 70 °F

    Partly Cloudy

  • Monday

    Monday: A 30 percent chance of showers before 1pm. Mostly sunny, with a high near 90.

    High: 90 °F

    Chance
    Showers

  • Monday Night

    Monday Night: A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 70.

    Low: 70 °F

    Chance
    T-storms

Detailed Forecast

This Afternoon
Sunny, with a high near 88. South wind around 5 mph.
Tonight
Showers and thunderstorms likely, mainly before 11pm. Partly cloudy, with a low around 73. Calm wind becoming southeast around 5 mph after midnight. Chance of precipitation is 70%.
Saturday
A 20 percent chance of showers and thunderstorms before 11am. Mostly sunny, with a high near 92. South wind 5 to 10 mph.
Saturday Night
A slight chance of showers and thunderstorms between 1am and 4am, then a slight chance of showers after 4am. Partly cloudy, with a low around 72. South wind around 5 mph becoming southeast after midnight. Chance of precipitation is 20%.
Sunday
Mostly sunny, with a high near 90.
Sunday Night
Partly cloudy, with a low around 70.
Monday
A 30 percent chance of showers before 1pm. Mostly sunny, with a high near 90.
Monday Night
A 40 percent chance of showers and thunderstorms. Partly cloudy, with a low around 70.
Tuesday
A chance of showers, with thunderstorms also possible after 1pm. Partly sunny, with a high near 86. Chance of precipitation is 30%.
Tuesday Night
Partly cloudy, with a low around 66.
Wednesday
Partly sunny, with a high near 81.
Wednesday Night
Mostly clear, with a low around 61.
Thursday
Mostly sunny, with a high near 80.
Basemap Options
Click map to change the forecast location
Loading map...
Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Lanark IL
 42.11°N 89.83°W (Elev. 883 ft)
Last Update:
12:32 pm CDT Aug 15, 2025
Forecast Valid:
2pm CDT Aug 15, 2025-6pm CDT Aug 21, 2025
 
Forecast Discussion
 
Get as KML Get as XML

Additional Resources

Radar & Satellite Image

Link to Local Radar Data Link to Satellite Data

Hourly Weather Forecast

National Digital Forecast Database

National Digital Forecast Database Maximum Temperature Forecast

High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation