The National Weather Service in Sacramento will issue an Excessive Heat Advisory
when the Heat Index is expected to reach 110 F for more than two hours
or nighttime heat index 75 F or more all night for delta-influenced counties and
nighttime heat index 80 degrees or more all night in the rest of the central valley
and lower foothills. The heat advisory for the mountains is issued for a heat index of 105 or
more for 2 or more hours or nighttime heat index of 75 F or greater all night.
National Weather Service Mission: "The
National Weather Service (NWS) provides weather,
hydrologic, and climate forecasts and warnings for
the United States, its territories, adjacent waters
and ocean areas, for the protection of life and
property and the enhancement of the national economy.
NWS data and products form a national information
database and infrastructure which can be used by
other governmental agencies, the private sector,
the public, and the global community."
www.weather.gov 
