The National Weather Service urged drivers in most of the Philadelphia region to use caution on roads because of dense fog Thursday morning.
The NWS issued a Dense Fog Advisory for all of South Jersey the northern half of Delaware, Philadelphia the immediate Pennsylvania suburban counties and Berks County through 11 a.m.
Visibility was reduced to less than a quarter of a mile in spots and the fog should persist until mid-morning, said forecasters.
The fog precedes an unseasonably warm February day as temps should get near or above 70 in many neighborhoods, the First Alert Weather Team said. [[287977901, C]]