* WHAT...High temperatures of 97 to 102 degrees with overnight lows of 55 to 70 degrees. Widespread Moderate to Major HeatRisk. * WHERE...In California, Lassen-Eastern Plumas-Eastern Sierra Counties and Surprise Valley California. In Nevada, Northern Washoe County and Greater Reno-Carson City-Minden Area. * WHEN...Until 8 AM PDT Monday. * IMPACTS...Heat related illnesses will be more likely, especially for those spending extended periods outdoors, in poorly cooled indoor spaces, or who are sensitive to heat.