Area emergency dispatchers are urging drivers to slow down on the roads tonight because a thick layer of fog has lowered visibility throughout Tennessee and North Georgia.

The National Weather Service at Morristown, Tenn., issued a dense fog advisory for most Southeast Tennessee counties. The advisory is in effect until 8 a.m. Tuesday.

"When traveling overnight, drive with caution and slow down," the advisory reads. "Give yourself extra room between you and the vehicle ahead of you."