Weather Alerts for California

Recent Locations: San Francisco, CA  
Current Alerts for San Francisco, CA: High Surf Advisory Wind Advisory

1. Avalanche Warning for: South Central Siskiyou County

2. Beach Hazards Statement for: Northern Monterey Bay

3. Flood Advisory for: Alameda, CA; Contra Costa, CA; Marin, CA

4. Flood Advisory for: Humboldt, CA

5. Flood Advisory for: Humboldt, CA; Mendocino, CA; Trinity, CA

6. Flood Advisory for: Lassen, CA; Plumas, CA; Sierra, CA

7. Flood Advisory for: Marin, CA; Sonoma, CA

8. Flood Advisory for: Napa, CA; Sonoma, CA

9. Flood Advisory for: Sonoma, CA

10. Flood Warning for: Siskiyou, CA

11. Flood Warning for: Siskiyou, CA; Coos, OR; Curry, OR; Jackson, OR; Josephine, OR

12. Flood Watch for: Coastal Del Norte; Del Norte Interior

13. Flood Watch for: Marin Coastal Range; Sonoma Coastal Range; North Bay Interior Mountains; Coastal North Bay Including Point Reyes National Seashore; North Bay Interior Valleys

14. Flood Watch for: Mendocino Coast; Northwestern Mendocino Interior; Northeastern Mendocino Interior; Southwestern Mendocino Interior; Southeastern Mendocino Interior

15. Flood Watch for: Northern Humboldt Coast; Southwestern Humboldt; Northern Humboldt Interior; Southern Humboldt Interior

16. Flood Watch for: Northern Lake County; Southern Lake County

17. Flood Watch for: Shasta Lake Area / Northern Shasta County; Northern Sacramento Valley; Central Sacramento Valley; Mountains Southwestern Shasta County to Western Colusa County; Northeast Foothills/Sacramento Valley

18. Flood Watch for: Southern Trinity

19. Frost Advisory for: Ojai Valley; Calabasas and Agoura Hills

20. High Surf Advisory for: San Francisco; Coastal North Bay Including Point Reyes National Seashore; San Francisco Peninsula Coast; Southern Monterey Bay and Big Sur Coast

21. High Surf Advisory for: San Luis Obispo County Beaches; Santa Barbara County Central Coast Beaches

22. High Wind Warning for: Central Siskiyou County

23. High Wind Warning for: Modoc County; Klamath Basin; Northern and Eastern Klamath County and Western Lake County; Central and Eastern Lake County

24. High Wind Warning for: Northeast Siskiyou and Northwest Modoc Counties

25. High Wind Watch for: Coastal Del Norte; Del Norte Interior; Northern Humboldt Coast; Southwestern Humboldt; Northern Humboldt Interior; Southern Humboldt Interior

26. Lake Wind Advisory for: Greater Lake Tahoe Area; Greater Lake Tahoe Area

27. Wind Advisory for: Mendocino Coast

28. Wind Advisory for: Modoc County; Klamath Basin; Northern and Eastern Klamath County and Western Lake County; Central and Eastern Lake County

29. Wind Advisory for: Northern Sacramento Valley; Central Sacramento Valley; Northeast Foothills/Sacramento Valley

30. Wind Advisory for: San Francisco; Marin Coastal Range; Sonoma Coastal Range; North Bay Interior Mountains; Coastal North Bay Including Point Reyes National Seashore; North Bay Interior Valleys; San Francisco Bay Shoreline; San Francisco Peninsula Coast

31. Winter Storm Warning for: Burney Basin / Eastern Shasta County; Western Plumas County/Lassen Park; West Slope Northern Sierra Nevada

32. Winter Storm Warning for: Northern Trinity

33. Winter Weather Advisory for: South Central Siskiyou County; North Central and Southeast Siskiyou County

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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 Cirrus Clouds?

Home - Education - Cloud Types - Cirrus Clouds

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

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