* WHAT. Visibility one quarter mile or less in dense fog. * WHERE. Portions of southwest North Carolina, east Tennessee, and southwest Virginia. * WHEN. Until 9 AM EDT /8 AM CDT/ this morning. * IMPACTS. Low visibility could make driving conditions hazardous.

..Patchy Dense Fog possible early this morning. Mostly clear skies, light winds, and lingering low-level moisture have led to areas of fog formation early this morning. The fog has become dense in some locations, reducing visibilities to one quarter of a mile or less at times. The fog should dissipate or thin at many locations when a weak cold front moves through. Motorists should exercise caution early this morning and be prepared for quick changes in visibility over short distances. Be sure to slow down and use your low beam headlights when you encounter fog.