* WHAT...High temperatures up to 108 degrees and multiple days of Major Heat Risk. * WHERE...San Joaquin Valley and adjacent foothills, Lake Isabella, and the Kern River Valley. * WHEN...Until 8 PM PDT Sunday. * IMPACTS...Heat related illnesses increase significantly during extreme heat events, especially those with little overnight relief from the heat. * ADDITIONAL DETAILS...Afternoon high temperatures of 105 to 108 degrees will occur daily through the upcoming weekend. Overnight lows will generally only fall into the mid 60s to mid 70s with little overnight relief.