* WHAT. Temperatures as low as 33 will result in frost formation. * WHERE. Portions of western Maryland, northwest and western Virginia, and eastern and panhandle West Virginia. * WHEN. From 2 AM to 9 AM EDT Thursday. * IMPACTS. Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered.

* WHAT. Temperatures as low as 33 will result in frost formation. * WHERE. In Maryland, Central and Eastern Allegany County. In Virginia, Warren County. In West Virginia, Morgan County. * WHEN. Until 9 AM EDT this morning. * IMPACTS. Frost could harm sensitive outdoor vegetation. Sensitive outdoor plants may be killed if left uncovered.

* WHAT. For the Frost Advisory, temperatures as low as 33 will result in frost formation. For the Freeze Watch, sub-freezing temperatures as low as 30 possible. * WHERE. Portions of western Maryland, northwest and western Virginia, and eastern West Virginia. * WHEN. For the Frost Advisory, until 9 AM EDT this morning. For the Freeze Watch, from late tonight through Friday morning. * IMPACTS. Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing.

* WHAT. North winds 10 to 15 kt with gusts up to 20 kt. * WHERE. Tidal Potomac from Indian Head to Cobb Island MD. * WHEN. Until 6 AM EDT Thursday. * IMPACTS. Conditions will be hazardous to small craft.

* WHAT. North winds 10 to 20 kt with gusts up to 25 kt. * WHERE. Chesapeake Bay from Pooles Island MD to Smith Point VA, Tidal Potomac from Cobb Island MD to Smith Point VA, Chester River to Queenstown MD, Eastern Bay, Choptank River to Cambridge MD and the Little Choptank River, and Tangier Sound and the inland waters surrounding Bloodsworth Island. * WHEN. Until 6 AM EDT Friday. * IMPACTS. Conditions will be hazardous to small craft.