Weather Alerts for California

Recent Locations: Richmond, VA Saint Marys, IA Vallejo, CA

1. Beach Hazards Statement for: Coastal Del Norte; Northern Humboldt Coast; Southwestern Humboldt; Mendocino Coast

2. Beach Hazards Statement for: San Francisco; Coastal North Bay Including Point Reyes National Seashore; San Francisco Peninsula Coast; Southern Monterey Bay and Big Sur Coast

3. Dense Fog Advisory for: Los Banos - Dos Palos; Merced - Madera - Mendota; Planada - Le Grand - Snelling; West Side of Fresno and Kings Counties; Caruthers - San Joaquin - Selma; Fresno-Clovis; Buttonwillow - Lost Hills - I5; Delano-Wasco-Shafter; Hanford - Corcoran - Lemoore; Visalia - Porterville - Reedley; Bakersfield; Southeast San Joaquin Valley

4. Wind Advisory for: Northern Sacramento Valley; Central Sacramento Valley; Southern Sacramento Valley

5. Winter Storm Watch for: Del Norte Interior; Northern Humboldt Interior; Southern Humboldt Interior

6. Winter Storm Watch for: Eastern Sierra Slopes of Inyo County

7. Winter Storm Watch for: Greater Lake Tahoe Area; Greater Lake Tahoe Area

8. Winter Storm Watch for: Lassen-Eastern Plumas-Eastern Sierra Counties

9. Winter Storm Watch for: Mariposa-Madera Lower Sierra; Fresno-Tulare Lower Sierra; South End of the Lower Sierra; Yosemite NP outside of the valley; Yosemite Valley; San Joaquin River Canyon; Upper San Joaquin River; Kaiser to Rodgers Ridge; Kings Canyon NP; Grant Grove Area; Sequoia NP; South End of the Upper Sierra; Piute Walker Basin

10. Winter Storm Watch for: Mono

11. Winter Storm Watch for: Northern Trinity; Southern Trinity

12. Winter Storm Watch for: Northwestern Mendocino Interior; Northeastern Mendocino Interior; Northern Lake County; Southern Lake County

13. Winter Storm Watch for: Shasta Lake Area / Northern Shasta County; Burney Basin / Eastern Shasta County; Mountains Southwestern Shasta County to Western Colusa County; Northeast Foothills/Sacramento Valley; Motherlode; Western Plumas County/Lassen Park; West Slope Northern Sierra Nevada

14. Winter Storm Watch for: South Central Siskiyou County; North Central and Southeast Siskiyou County

15. Winter Storm Watch for: South Central Siskiyou County; North Central and Southeast Siskiyou County

16. Winter Storm Watch for: Western Siskiyou County

17. Winter Storm Watch for: Western Siskiyou County

18. Winter Storm Watch for: White Mountains of Inyo County

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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 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