* WHAT. For Apple and Lucerne Valleys: High temperatures from 99 to 104 degrees. Wednesday will be the hottest day. For the Coachella Valley and San Diego County Deserts: High temperatures from 108 to 113 degrees. Friday will be the hottest day. * WHERE. Apple and Lucerne Valleys; Coachella Valley; and San Diego County Deserts. * WHEN. Wednesday through Friday. * IMPACTS. Increased potential for heat related illnesses, especially for those not yet acclimated to summer heat.

* WHAT. A moderate-rough NW swell will create large breaking waves of 15-20 ft and an increased risk for sneaker waves. * WHERE. San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties. * WHEN. From Wednesday morning through Thursday evening. * IMPACTS. Large waves can sweep across beaches without warning. * ADDITIONAL DETAILS. There are two hazards to be aware of, high surf and sneaker waves. Large breaking waves create a hazardous surf zone with breaking waves of 15-20 ft, especially along steep beaches. Sneaker waves can run over 100 ft up a dry beach, pulling people in into the water from rocks, jetties, and beaches.

* WHAT. A moderate-rough NW swell will create large breaking waves of 15-20 ft and an increased risk for sneaker waves. * WHERE. San Francisco, Coastal North Bay Including Point Reyes National Seashore, San Francisco Peninsula Coast and Southern Monterey Bay and Big Sur Coast Counties. * WHEN. From Wednesday morning through Thursday evening. * IMPACTS. Large waves can sweep across beaches without warning. * ADDITIONAL DETAILS. There are two hazards to be aware of, high surf and sneaker waves. Large breaking waves create a hazardous surf zone with breaking waves of 15-20 ft, especially along steep beaches. Sneaker waves can run over 100 ft up a dry beach, pulling people in into the water from rocks, jetties, and beaches.

* WHAT. West winds 10 to 15 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 3 PM this afternoon to 9 PM PDT this evening. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. Dangerously hot conditions with temperatures up to 109 expected. * WHERE. San Gorgonio Pass Near Banning. * WHEN. From 10 AM Wednesday to 9 PM PDT Friday. * IMPACTS. Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities.

* WHAT. Dangerously hot conditions with temperatures 95 to 108 possible and widespread Major HeatRisk. Limited overnight relief with low temperatures in the 60s to mid 70s. * WHERE. Carquinez Strait and Delta, Sacramento Valley, Motherlode, Mountains Southwestern Shasta County to Western Colusa County, Northeast Foothills, Northern San Joaquin Valley, and portions of Shasta County. * WHEN. From 11 AM PDT Tuesday to 8 PM PDT Thursday. * IMPACTS. Heat related illnesses increase significantly during extreme heat events, particularly for those working or participating in outdoor activities. * ADDITIONAL DETAILS. Hottest temperatures are expected Wednesday. Area waterways will continue to run cold and fast, creating dangerous conditions for those seeking relief in rivers and lakes.