Weather Alerts for California

Recent Locations: San Francisco International Airport, CA

1. Air Quality Alert for: Calabasas and Agoura Hills; Eastern San Fernando Valley; Eastern San Gabriel Mountains; Eastern Santa Monica Mountains Recreational Area; Interstate 5 Corridor; Los Angeles County Beaches; Los Angeles County Inland Coast including Downtown Los Angeles; Los Angeles County San Gabriel Valley; Santa Clarita Valley; Santa Susana Mountains; Western San Fernando Valley; Western San Gabriel Mountains and Highway 14 Corridor; Western Santa Monica Mountains Recreational Area

2. Air Quality Alert for: Calabasas and Agoura Hills; Eastern San Fernando Valley; Eastern San Gabriel Mountains; Interstate 5 Corridor; Los Angeles County Inland Coast including Downtown Los Angeles; Los Angeles County San Gabriel Valley; Santa Clarita Valley; Santa Susana Mountains; Western San Fernando Valley; Western San Gabriel Mountains and Highway 14 Corridor

3. Air Quality Alert for: Calabasas and Agoura Hills; Eastern San Fernando Valley; Eastern San Gabriel Mountains; Interstate 5 Corridor; Los Angeles County Inland Coast including Downtown Los Angeles; Los Angeles County San Gabriel Valley; Santa Clarita Valley; Santa Susana Mountains; Western San Fernando Valley; Western San Gabriel Mountains and Highway 14 Corridor

4. Air Quality Alert for: Calabasas and Agoura Hills; Eastern San Fernando Valley; Eastern San Gabriel Mountains; Interstate 5 Corridor; Los Angeles County Inland Coast including Downtown Los Angeles; Los Angeles County San Gabriel Valley; Santa Clarita Valley; Santa Susana Mountains; Western San Fernando Valley; Western San Gabriel Mountains and Highway 14 Corridor

5. Air Quality Alert for: San Bernardino and Riverside County Valleys-The Inland Empire; San Bernardino County Mountains; Riverside County Mountains; Santa Ana Mountains and Foothills; Coachella Valley; San Gorgonio Pass Near Banning; Orange County Inland

6. Extreme Heat Warning for: Coachella Valley; San Diego County Deserts; San Gorgonio Pass Near Banning

7. Extreme Heat Warning for: Joshua Tree NP West; Joshua Tree NP East; Imperial County Southwest; Salton Sea; Chuckwalla Mountains; Imperial County Southeast; Imperial County West; Imperial Valley; Chiriaco Summit; Palo Verde Valley; Chuckwalla Valley

8. Extreme Heat Watch for: Del Norte Interior; Northern Humboldt Interior; Southern Humboldt Interior

9. Extreme Heat Watch for: Western Siskiyou County; Central Siskiyou County; Eastern Curry County and Josephine County; Jackson County

10. Heat Advisory for: Northern Trinity; Southern Trinity; Northeastern Mendocino Interior; Northern Lake County; Southern Lake County

11. Heat Advisory for: Northwestern Mendocino Interior; Southeastern Mendocino Interior

12. Heat Advisory for: Riverside County Mountains; San Diego County Mountains

13. Heat Advisory for: San Bernardino and Riverside County Valleys-The Inland Empire

14. Heat Advisory for: San Diego County Inland Valleys

15. Heat Advisory for: Shasta Lake Area / Northern Shasta County; Burney Basin / Eastern Shasta County; Northern Sacramento Valley; Central Sacramento Valley; Mountains Southwestern Shasta County to Western Colusa County; Northeast Foothills/Sacramento Valley; Western Plumas County/Lassen Park

16. Wind Advisory for: Santa Barbara County Southwestern Coast; Santa Ynez Mountains Western Range

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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).

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 Nimbostratus Clouds?

Home - Education - Cloud Types - Nimbostratus Clouds

Nimbostratus Clouds Next Topic: Precipitation

A nimbostratus cloud is similar to a stratus cloud in its formless, smooth appearance. However, a nimbostratus cloud is darker than a stratus cloud, because it is thicker.

Unlike a stratus cloud, a nimbostratus cloud typically brings with it the threat of moderate to heavy precipitation. In some cases, the precipitation may evaporate before reaching the ground, a phenomenon known as virga.

Next Topic: Precipitation

Weather Topic: What is Rain?

Home - Education - Precipitation - Rain

Rain Next Topic: Shelf Clouds

Precipitation in the form of water droplets is called rain. Rain generally has a tendency to fall with less intensity over a greater period of time, and when rainfall is more severe it is usually less sustained.

Rain is the most common form of precipitation and happens with greater frequency depending on the season and regional influences. Cities have been shown to have an observable effect on rainfall, due to an effect called the urban heat island. Compared to upwind, monthly rainfall between twenty and forty miles downwind of cities is 30% greater.

Next Topic: Shelf Clouds