* WHAT...Hot temperatures of 95 to 105 degrees are expected, possibly up to 110 degrees in the lower Klamath River Valley, with low temperatures in the 50s to near 60 degrees. Lows of 60 to 65 degrees over higher terrain. * WHERE...Central Siskiyou County, Modoc County, North Central and Southeast Siskiyou County, Northeast Siskiyou and Northwest Modoc Counties, and Western Siskiyou County. This includes the lower Klamath River Valley, the Shasta Valley, Weed, Montague, Alturas, Tionesta, Tennant, Macdoel and Tulelake. * WHEN...Until 11 PM PDT Saturday. * IMPACTS...Hot temperatures will lead to a moderate risk of heat illnesses, especially for those without adequate cooling methods. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors.