Forecast Details for Herndon, VA

Recent Locations: Herndon, VA

Today: Showers and possibly a thunderstorm after 5pm. High near 67. Calm wind becoming south 5 to 7 mph in the afternoon. Chance of precipitation is 80%. New rainfall amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Tonight: Showers and possibly a thunderstorm before 2am, then a chance of showers between 2am and 5am. Low around 49. Southeast wind around 7 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.

Sunday: A slight chance of showers between 8am and 2pm, then a chance of showers and thunderstorms after 2pm. Mostly sunny, with a high near 66. Northwest wind 7 to 13 mph. Chance of precipitation is 30%.

Sunday Night: A chance of showers before 8pm. Mostly clear, with a low around 49. North wind around 6 mph becoming calm after midnight. Chance of precipitation is 30%.

Monday: Mostly sunny, with a high near 76. South wind 6 to 14 mph, with gusts as high as 20 mph.

Monday Night: A chance of showers after 2am. Mostly cloudy, with a low around 59. Chance of precipitation is 40%.

Tuesday: A chance of showers, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 73. Chance of precipitation is 70%.

Tuesday Night: Showers and possibly a thunderstorm before 2am, then a chance of showers. Low around 62. Chance of precipitation is 80%.

Wednesday: A chance of showers, then showers likely and possibly a thunderstorm after 2pm. Mostly cloudy, with a high near 75. Chance of precipitation is 60%.

Wednesday Night: Showers likely and possibly a thunderstorm before 8pm, then a chance of showers and thunderstorms between 8pm and 2am. Partly cloudy, with a low around 57. Chance of precipitation is 60%.

Thursday: Mostly sunny, with a high near 76.

Thursday Night: A chance of showers. Partly cloudy, with a low around 58. Chance of precipitation is 30%.

Friday: A chance of showers. Mostly cloudy, with a high near 74. Chance of precipitation is 50%.

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Current U.S. National Radar--Current

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National Weather Forecast--Current

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National Weather Forecast for Tomorrow

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North America Water Vapor (Moisture)

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Weather Topic: What are Cirrus Clouds?

Home - Education - Cloud Types - Cirrus Clouds

Next Topic: Condensation

Cirrus clouds are high-level clouds that occur above 20,000 feet and are composed mainly of ice crystals. They are thin and wispy in appearance.

What do they indicate?
They are often the first sign of an approaching storm.

Next Topic: Condensation

Weather Topic: What are Contrails?

Home - Education - Cloud Types - Contrails

Next Topic: Cumulonimbus Clouds

A contrail is an artificial cloud, created by the passing of an aircraft.

Contrails form because water vapor in the exhaust of aircraft engines is suspended in the air under certain temperatures and humidity conditions. These contrails are called exhaust contrails.

Another type of contrail can form due to a temporary reduction in air pressure moving over the plane's surface, causing condensation. These are called aerodynamic contrails.

When you can see your breath on a cold day, it is also because of condensation. The reason contrails last longer than the condensation from your breath is because the water in contrails freezes into ice particles.

Next Topic: Cumulonimbus Clouds