* WHAT…For the Extreme Heat Warning, dangerously hot conditions. Afternoon temperatures 108 to 114. Major Heat Risk. For the Extreme Heat Watch, dangerously hot conditions possible. Afternoon temperatures 108 to 118. Extreme Heat Risk. * WHERE…Sonoran Desert National Monument, Aguila Valley, Tonopah Desert, Gila Bend, Cave Creek/New River, Fountain Hills/East Mesa, Superior, Northwest Pinal County, West Pinal County, and Apache Junction/Gold Canyon. * WHEN…For the Extreme Heat Warning, until 8 PM MST this evening. For the Extreme Heat Watch, from Tuesday morning through Friday evening. * IMPACTS…Heat related illnesses increase significantly during extreme heat events. Overexposure can cause heat cramps and heat exhaustion to develop and, without intervention, can lead to heat stroke.