* WHAT. Southwest winds 10 to 15 kt with gusts up to 21 kt and a moderate chop expected. * WHERE. San Pablo Bay, Suisun Bay, the West Delta and the San Francisco Bay north of the Bay Bridge. * WHEN. From 9 AM to 9 PM PDT Thursday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. For the Beach Hazards Statement, a moderate period northwesterly swell will result in an increased risk for sneaker waves and rip currents. For the High Surf Advisory, long period very high northwest swell will result in large breaking waves between 25 to 30 feet on north and west facing beaches. * WHERE. San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast. * WHEN. For the Beach Hazards Statement, until 11 AM PDT this morning. For the High Surf Advisory, from 5 AM Thursday to 11 AM PDT Friday. * IMPACTS. Dangerous swimming and surfing conditions and localized beach erosion. Sneaker waves can unexpectedly run significantly farther up the beach than normal, including over rocks and jetties. These waves can suddenly knock people off their feet and quickly pull them into the cold ocean waters, where currents will be stronger than normal. These waves can also carry driftwood logs and other debris.

* WHAT. The South Coast AQMD has extended an air quality alert due to harmful levels of particle pollution from windblown dust. * WHERE. in the Coachella Valley. Levels of particle pollution can vary by time and location depending on emissions and local weather conditions. * WHEN. until 11:59 PM Friday. * IMPACTS. Particle pollution can get deep into the lungs and cause serious health problems such as asthma attacks, heart and lung disease symptoms, and increased risk of lung infections. Everyone can be affected, but sensitive groups such as people with lung or heart disease, older adults, people who are pregnant, children, and those who spend a lot of time outdoors are at greater risk.

* WHAT. Long period very high northwest swell will result in large breaking waves between 25 to 30 feet on north and west facing beaches. * WHERE. San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast. * WHEN. From 5 AM Thursday to 11 AM PDT Friday. * IMPACTS. Dangerous swimming and surfing conditions and localized beach erosion. Sneaker waves can unexpectedly run significantly farther up the beach than normal, including over rocks and jetties. These waves can suddenly knock people off their feet and quickly pull them into the cold ocean waters, where currents will be stronger than normal. These waves can also carry driftwood logs and other debris.

* WHAT. Southwest winds 10 to 15 kt with gusts up to 25 kt and a moderate chop expected. * WHERE. San Pablo Bay, Suisun Bay, the West Delta and the San Francisco Bay north of the Bay Bridge. * WHEN. From 9 AM to 9 PM PDT Thursday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. The South Coast AQMD has issued an air quality alert due to harmful levels of particle pollution from windblown dust. * WHERE. in the Coachella Valley. Levels of particle pollution can vary by time and location depending on emissions and local weather conditions. * WHEN. from 8AM Wednesday to 11AM Thursday. * IMPACTS. Particle pollution can get deep into the lungs and cause serious health problems such as asthma attacks, heart and lung disease symptoms, and increased risk of lung infections. Everyone can be affected, but sensitive groups such as people with lung or heart disease, older adults, people who are pregnant, children, and those who spend a lot of time outdoors are at greater risk.