Forecast Details for Philadelphia, PA

Recent Locations: New York City, NY Philadelphia, PA

Current Alerts for Philadelphia, PA: Air Quality Alert

Tonight: Mostly clear, with a low around 77. Calm wind.

Wednesday: Sunny and hot, with a high near 98. Heat index values as high as 104. Calm wind becoming southwest around 5 mph in the afternoon.

Wednesday Night: A slight chance of showers. Partly cloudy, with a low around 76. Southwest wind around 5 mph. Chance of precipitation is 20%.

Thursday: A chance of showers before 11am, then a chance of showers and thunderstorms between 11am and 2pm, then showers likely and possibly a thunderstorm after 2pm. Some of the storms could produce heavy rainfall. Partly sunny, with a high near 90. South wind around 5 mph becoming east in the afternoon. Chance of precipitation is 70%. New rainfall amounts between a quarter and half of an inch possible.

Thursday Night: Showers and possibly a thunderstorm. Some of the storms could produce heavy rainfall. Low around 67. Northeast wind around 5 mph. Chance of precipitation is 80%. New rainfall amounts between 1 and 2 inches possible.

Friday: Showers likely and possibly a thunderstorm before 8am, then a chance of showers and thunderstorms after 8am. Cloudy, with a high near 71. Chance of precipitation is 60%. New rainfall amounts between a half and three quarters of an inch possible.

Friday Night: Mostly cloudy, with a low around 62.

Saturday: Sunny, with a high near 80.

Saturday Night: Mostly clear, with a low around 61.

Sunday: Sunny, with a high near 84.

Sunday Night: Partly cloudy, with a low around 64.

Monday: Mostly sunny, with a high near 85.

Monday Night: Mostly cloudy, with a low around 65.

Tuesday: Partly sunny, with a high near 86.

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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

Tomorrow National Weather Forecast and Tomorrow National Weather Map are show below.

North America Water Vapor (Moisture)

This map shows recent moisture content over North America. Bright and colored areas show high moisture (ie, clouds); brown indicates very little moisture present; black indicates no moisture.

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