* WHAT...Temperatures as low as 32 will result in frost formation. * WHERE...Calhoun, Eaton, Ingham, Jackson, Allegan, Barry, Kalamazoo, and Van Buren Counties. * WHEN...From midnight tonight to 8 AM EDT Saturday. * IMPACTS...Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered. Take steps now to protect tender plants from the cold.