Forecast Details for Castro Valley, CA

Recent Locations: Haines, AK   Castro Valley, CA  
This Afternoon: Sunny, with a high near 68. West southwest wind 11 to 13 mph, with gusts as high as 21 mph.
Tonight: Increasing clouds, with a low around 55. West southwest wind 7 to 11 mph, with gusts as high as 21 mph.
Sunday: Mostly cloudy, then gradually becoming sunny, with a high near 72. West southwest wind 6 to 11 mph, with gusts as high as 18 mph.
Sunday Night: Mostly cloudy, with a low around 59. West southwest wind 6 to 10 mph.
Monday: Partly sunny, with a high near 71. West wind 7 to 13 mph, with gusts as high as 21 mph.
Monday Night: Mostly cloudy, with a low around 55.
Tuesday: Sunny, with a high near 86.
Tuesday Night: Mostly clear, with a low around 61.
Wednesday: Sunny, with a high near 89.
Wednesday Night: Mostly clear, with a low around 58.
Thursday: Sunny, with a high near 82.
Thursday Night: Partly cloudy, with a low around 56.
Friday: Sunny, with a high near 77.

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Current U.S. National Radar--Current

The Current National Weather Radar is shown below with a UTC Time (subtract 5 hours from UTC to get Eastern Time).

Current U.S. National Radar

National Weather Forecast--Current

The Current National Weather Forecast and National Weather Map are shown below.

Today's National Weather Map

National Weather Forecast for Tomorrow

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

Tomorrows National Weather Map

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.

North American Water Vapor Map

Weather Topic: What are Cumulonimbus Clouds?

Home - Education - Cloud Types - Cumulonimbus Clouds

Cumulonimbus Clouds Next Topic: Cumulus Clouds

The final form taken by a growing cumulus cloud is the cumulonimbus cloud, which is very tall and dense. The tower of a cumulonimbus cloud can soar 23 km into the atmosphere, although most commonly they stop growing at an altitude of 6 km.

Even small cumulonimbus clouds appear very large in comparison to other cloud types. They can signal the approach of stormy weather, such as thunderstorms or blizzards.

Next Topic: Cumulus Clouds

Weather Topic: What is Drizzle?

Home - Education - Precipitation - Drizzle

Drizzle Next Topic: Evaporation

Drizzle is precipitation in the form of water droplets which are smaller than raindrops.

Drizzle is characterized by fine, gently falling droplets and typically does not impact human habitation in a negative way. The exception to this is freezing drizzle, a condition where drizzle freezes immediately upon reaching earth's surface. Freezing drizzle is still less dangerous than freezing rain, but can potentially result in hazardous road conditions.

Next Topic: Evaporation