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Tropical System in the Gulf; Dangerous Heat and Air Quality Concerns; Severe Thunderstorms for Midwest to mid-Atlantic

Tropical system in the Gulf expected to gradually strengthen the next couple of days off the Florida Panhandle and Alabama coasts. Instances of flash flooding will be possible through Thursday along the eastern and central Gulf Coast. Severe thunderstorms will develop and move along a cold front crossing the Upper Midwest, and through the Ohio Valley/Mid-Atlantic on Tuesday. Read More >

Hazardous Weather Conditions

Current conditions at

Sherman/Denison, Grayson County Airport (KGYI)

Lat: 33.72°NLon: 96.67°WElev: 748ft.

Fair

84°F

29°C

Humidity 70%
Wind Speed SW 9 mph
Barometer 29.99 in
Dewpoint 73°F (23°C)
Visibility 9.00 mi
Heat Index90°F (32°C)
Last update 20 Jul 8:50 am CDT
Extended Forecast for

Grayson County Airport TX

Heat Advisory July 20, 12:00pm until July 20, 08:00pm
Click here for hazard details and duration
Heat Advisory

  • Today

    Today: Sunny and hot, with a high near 99. Heat index values as high as 105. West southwest wind 5 to 10 mph.

    High: 99 °F

    Hot

  • Tonight

    Tonight: Mostly clear, with a low around 77. South southwest wind around 5 mph.

    Low: 77 °F

    Mostly Clear

  • Tuesday

    Tuesday: Sunny and hot, with a high near 101. Heat index values as high as 106. West southwest wind around 5 mph.

    High: 101 °F

    Hot

  • Tuesday Night

    Tuesday Night: Clear, with a low around 80. South wind around 5 mph becoming west after midnight.

    Low: 80 °F

    Clear

  • Wednesday

    Wednesday: Sunny and hot, with a high near 100. North wind 5 to 10 mph becoming east northeast in the afternoon.

    High: 100 °F

    Hot

  • Wednesday Night

    Wednesday Night: Clear, with a low around 78. East northeast wind around 10 mph.

    Low: 78 °F

    Clear

  • Thursday

    Thursday: Sunny, with a high near 97. East southeast wind around 10 mph.

    High: 97 °F

    Sunny

  • Thursday Night

    Thursday Night: Clear, with a low around 78. East southeast wind around 10 mph.

    Low: 78 °F

    Clear

  • Friday

    Friday: Sunny, with a high near 98. South southeast wind around 10 mph.

    High: 98 °F

    Sunny

Detailed Forecast

Today
Sunny and hot, with a high near 99. Heat index values as high as 105. West southwest wind 5 to 10 mph.
Tonight
Mostly clear, with a low around 77. South southwest wind around 5 mph.
Tuesday
Sunny and hot, with a high near 101. Heat index values as high as 106. West southwest wind around 5 mph.
Tuesday Night
Clear, with a low around 80. South wind around 5 mph becoming west after midnight.
Wednesday
Sunny and hot, with a high near 100. North wind 5 to 10 mph becoming east northeast in the afternoon.
Wednesday Night
Clear, with a low around 78. East northeast wind around 10 mph.
Thursday
Sunny, with a high near 97. East southeast wind around 10 mph.
Thursday Night
Clear, with a low around 78. East southeast wind around 10 mph.
Friday
Sunny, with a high near 98. South southeast wind around 10 mph.
Friday Night
Mostly clear, with a low around 79.
Saturday
Mostly sunny, with a high near 98.
Saturday Night
Mostly clear, with a low around 79.
Sunday
Sunny and hot, with a high near 99.
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Forecast Area
Tiles ©ESRI

ABOUT THIS FORECAST

 
Point Forecast:
Grayson County Airport TX
 33.71°N 96.66°W (Elev. 797 ft)
Last Update:
6:06 am CDT Jul 20, 2026
Forecast Valid:
9am CDT Jul 20, 2026-6pm CDT Jul 26, 2026
 
Forecast Discussion
 
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Additional Resources

Radar & Satellite Image

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Hourly Weather Forecast

National Digital Forecast Database

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High Temperature

National Digital Forecast Database Weather Element Forecast

Chance of Precipitation