* WHAT...High temperatures of 97 to 102 degrees with overnight lows of 55 to 70 degrees. Widespread Moderate (level 2 out of 4) HeatRisk with areas of Major HeatRisk (level 3 out of 4) in lower Nevada valleys. * 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. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.