Fog, locally dense, has developed in river valleys this morning. If commuting through these areas, take it slow and use low-beam headlights, increase following distance, and be alert for slow- moving traffic, pedestrians, and animals. For places that are below freezing, pay attention to any slick spots that may form on roadways.

* WHAT…Sub-freezing temperatures as low as the upper 20s are expected. * WHERE…Portions of south central Indiana and east central, north central, northwest, and south central Kentucky. * WHEN…Until 10 AM EST /9 AM CST/ this morning. * IMPACTS…Frost and freeze conditions could kill crops, other sensitive vegetation and possibly damage unprotected outdoor plumbing.

What to do: Take steps now to protect tender plants from the cold. To prevent water pipes from freezing; wrap or drain or allow them to drip slowly.