* WHAT...Temperatures in the mid 30s will result in frost formation. * WHERE...In Oklahoma, Northeast Osage, Pawnee, Southeast Osage, Washington, and Western Osage Counties. * WHEN...From 1 AM to 9 AM CDT Saturday. * IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered. Cover outdoor plants or bring them indoors.