* WHAT...High temperatures up to 102 and morning lows up to 75 expected. Widespread Moderate HeatRisk will be present with areas of Major HeatRisk in the foothills where the thermal belt is strongest and in urban areas.
* WHERE...The San Joaquin Valley, Sierra Nevada Foothills, and West Side Hills along the Coastal Range.
* WHEN...From 10 AM Wednesday to 10 PM PDT Thursday.
* IMPACTS...Hot temperatures may cause heat illnesses, especially those without effective cooling and/or adequate hydration.
* ADDITIONAL DETAILS...Little to no relief at night in areas of Major HeatRisk. Air conditioning is necessary; fans and open windows at night will not be enough.