A weather alert was issued by the National Weather Service on Friday at 5:09 a.m. for dense fog until 9 a.m. for Oneida, Seneca, Cayuga, Onondaga, Madison and Cortland counties."Patchy dense fog has formed across the region this morning reducing visibilities to a quarter mile or less at times. If traveling, allow for extra time to reach your destination due to reduced visibilities," according to the weather service.