* WHAT...Sub-freezing temperatures as low as 30 expected.
* WHERE...Campbell, Corson, Dewey, Edmunds, McPherson, Potter, Walworth, and Brown Counties.
* WHEN...From 3 AM CDT /2 AM MDT/ to 9 AM CDT /8 AM MDT/ Wednesday.
* IMPACTS...Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing.