After recent rains drenched the Central Valley, dense fog is now rolling in through the holiday weekend. Murky conditions blanketed the region Friday morning, earning a dense-fog advisory through 10 a.m. due to visibility of less than a quarter of a mile. The most affected areas included Bakersfield, Delano and the southern portion of Interstate 5, Stephen McCoy, a meteorologist with the National Weather Service, told SFGATE.