Dense fog reduces visibility to less than a quarter-mile

 SAN DIEGO (KUSI) — Dense fog along the San Diego County coastline could slow down the morning commute Wednesday.

Visibility in several areas across San Diego County was reduced to zero miles per hour in the early morning hours Wednesday. A National Weather Service dense fog advisory for the coastal areas will expire at 8 a.m., around the same time the fog is expected to dissipate. The advisory applies to the cities of Carlsbad, Chula Vista, Encinitas, National City, San Diego and Vista.

Forecasters said the fog "should be quick to clear out, but will negatively impact the coastal commute this morning." Drivers were urged to slow down, use their low beams and stay well back from vehicles ahead of them.

Some clouds may persist throughout the day. Conditions will be warm and pleasant. Wednesday’s high temperatures are expected to be 75 degrees along the coast, 80 degrees inland, 55 degrees for the mountains and 76 degrees in the deserts. 

Patchy fog is expected to develop along the coast again overnight, according to the weather service.