* WHAT...Hot conditions with afternoon temperatures of 90 to 100 degrees, locally higher in Hells Canyon. This will pose a moderate to major risk of heat-related illness. * WHERE...In Oregon, Foothills of the Northern Blue Mountains of Oregon, Grande Ronde Valley, and Wallowa County. In Washington, Yakima Valley, Lower Columbia Basin of Washington, and Foothills of the Blue Mountains of Washington. * WHEN...Until 9 PM PDT this evening. * IMPACTS...Hot temperatures may cause heat illnesses.