Major Heat Wave Expected for Two-Thirds of the U.S.

A dangerous and widespread summer heat wave is expected through this upcoming weekend across much of the Central and Eastern U.S. A large dome of high pressure will allow high temperatures to surge into the 90s and 100s in many locations, while heat indices will top 100 and approach 110 degrees or higher. There also will be no relief at night, as low temperatures remain in the upper 70s and 80s. Read More >

Current conditions at

Washington/Dulles International Airport, DC (KIAD)

Lat: 38.93°NLon: 77.45°WElev: 312ft.

Mostly Cloudy

31°C

88°F

Humidity 61%
Wind Speed S 11 km/h
Barometer 1015.4 mb (30.00 in)
Dewpoint 23°C (73°F)
Visibility 16 km
Heat Index36°C (96°F)
Last update 17 Jul 9:52 am EDT
Extended Forecast for

Herndon VA

Heat Advisory July 17, 11:00am until July 17, 08:00pm
Click here for hazard details and duration
Heat Advisory
  • Today

    Today: Isolated showers and thunderstorms between 2pm and 5pm, then showers likely and possibly a thunderstorm after 5pm.  Partly sunny and hot, with a high near 36. Heat index values as high as 40. Southwest wind 8 to 16 km/h.  Chance of precipitation is 60%. New rainfall amounts of less than 1 mm, except higher amounts possible in thunderstorms.

    Mostly Sunny
    then Showers
    Likely

    High: 36 °C

  • Tonight

    Tonight: Showers likely and possibly a thunderstorm before 11pm, then isolated showers. Some of the storms could produce gusty winds and heavy rain.  Mostly cloudy, with a low around 24. Southwest wind 8 to 11 km/h.  Chance of precipitation is 60%. New precipitation amounts between 1 and 2.5 mm, except higher amounts possible in thunderstorms.

    Heavy Rain
    then Isolated
    Showers

    Low: 24 °C

  • Thursday

    Thursday: Scattered showers and thunderstorms.  Mostly cloudy, with a high near 33. Heat index values as high as 38. West wind 8 to 10 km/h.  Chance of precipitation is 40%.

    Scattered
    Showers then
    Scattered
    T-storms

    High: 33 °C

  • Thursday
    Night

    Thursday Night: Scattered thunderstorms before 8pm.  Partly cloudy, with a low around 23. Calm wind.  Chance of precipitation is 30%.

    Scattered
    T-storms then
    Partly Cloudy

    Low: 23 °C

  • Friday

    Friday: Sunny and hot, with a high near 37. West wind 3 to 8 km/h.

    Hot

    High: 37 °C

  • Friday
    Night

    Friday Night: Partly cloudy, with a low around 26.

    Partly Cloudy

    Low: 26 °C

  • Saturday

    Saturday: Mostly sunny and hot, with a high near 38.

    Hot

    High: 38 °C

  • Saturday
    Night

    Saturday Night: Partly cloudy, with a low around 26.

    Partly Cloudy

    Low: 26 °C

  • Sunday

    Sunday: A chance of showers and thunderstorms.  Mostly sunny and hot, with a high near 37. Chance of precipitation is 30%.

    Chance
    T-storms

    High: 37 °C

Detailed Forecast

Today
Isolated showers and thunderstorms between 2pm and 5pm, then showers likely and possibly a thunderstorm after 5pm. Partly sunny and hot, with a high near 36. Heat index values as high as 40. Southwest wind 8 to 16 km/h. Chance of precipitation is 60%. New rainfall amounts of less than 1 mm, except higher amounts possible in thunderstorms.
Tonight
Showers likely and possibly a thunderstorm before 11pm, then isolated showers. Some of the storms could produce gusty winds and heavy rain. Mostly cloudy, with a low around 24. Southwest wind 8 to 11 km/h. Chance of precipitation is 60%. New precipitation amounts between 1 and 2.5 mm, except higher amounts possible in thunderstorms.
Thursday
Scattered showers and thunderstorms. Mostly cloudy, with a high near 33. Heat index values as high as 38. West wind 8 to 10 km/h. Chance of precipitation is 40%.
Thursday Night
Scattered thunderstorms before 8pm. Partly cloudy, with a low around 23. Calm wind. Chance of precipitation is 30%.
Friday
Sunny and hot, with a high near 37. West wind 3 to 8 km/h.
Friday Night
Partly cloudy, with a low around 26.
Saturday
Mostly sunny and hot, with a high near 38.
Saturday Night
Partly cloudy, with a low around 26.
Sunday
A chance of showers and thunderstorms. Mostly sunny and hot, with a high near 37. Chance of precipitation is 30%.
Sunday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 25. Chance of precipitation is 30%.
Monday
Showers and thunderstorms likely. Mostly cloudy, with a high near 33. Chance of precipitation is 60%.
Monday Night
A chance of showers and thunderstorms. Mostly cloudy, with a low around 21. Chance of precipitation is 50%.
Tuesday
A chance of showers and thunderstorms. Partly sunny, with a high near 29. Chance of precipitation is 40%.
Click Map For Forecast
Point Forecast:
Herndon VA
 38.97°N 77.38°W (Elev. 108 m)
7:30 am EDT Jul 17, 2019
10am EDT Jul 17, 2019-6pm EDT Jul 23, 2019
 
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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