Forecast Details for Johnstown, PA

Recent Locations: Point Arena, CA Menomonee Falls, WI Johnstown, PA

Tonight: Mostly cloudy, with a low around 46. Light south wind.

Thursday: Showers, mainly after 3pm. High near 55. Calm wind becoming southeast 5 to 8 mph in the afternoon. Winds could gust as high as 20 mph. Chance of precipitation is 80%. New precipitation amounts between a tenth and quarter of an inch possible.

Thursday Night: Showers. Low around 41. Southeast wind 7 to 9 mph, with gusts as high as 23 mph. Chance of precipitation is 90%. New precipitation amounts between a quarter and half of an inch possible.

Friday: Showers likely, mainly between 7am and 1pm. Partly sunny, with a high near 60. South wind 7 to 11 mph becoming west in the afternoon. Winds could gust as high as 25 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.

Friday Night: A slight chance of rain showers, mixing with snow after 10pm, then gradually ending. Mostly cloudy, with a low around 34. West wind around 9 mph, with gusts as high as 24 mph. Chance of precipitation is 20%.

Saturday: Partly sunny, with a high near 46.

Saturday Night: A chance of snow showers after 1am. Mostly cloudy, with a low around 30. Chance of precipitation is 30%.

Sunday: Snow showers. High near 39. Chance of precipitation is 80%.

Sunday Night: Snow showers likely, mainly before 1am. Mostly cloudy, with a low around 26. Chance of precipitation is 60%.

Monday: A chance of snow showers. Mostly cloudy, with a high near 35. Chance of precipitation is 40%.

Monday Night: Mostly cloudy, with a low around 19.

Tuesday: Partly sunny, with a high near 32.

Tuesday Night: Partly cloudy, with a low around 21.

Wednesday: A chance of showers. Mostly cloudy, with a high near 43. Chance of precipitation is 30%.

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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 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

Weather Topic: What are Cumulus Clouds?

Home - Education - Cloud Types - Cumulus Clouds

Next Topic: Drizzle

Cumulus clouds are fluffy and textured with rounded tops, and may have flat bottoms. The border of a cumulus cloud is clearly defined, and can have the appearance of cotton or cauliflower.

Cumulus clouds form at low altitudes (rarely above 2 km) but can grow very tall, becoming cumulus congestus and possibly the even taller cumulonimbus clouds. When cumulus clouds become taller, they have a greater chance of producing precipitation.

Next Topic: Drizzle