The National Weather Service released a dense fog advisory at 7:06 a.m. on Saturday in effect until 9 a.m. for Lawrence, Butler, Beaver and Allegheny counties.

The weather service says to anticipate, "Visibility one to two miles in dense fog."

"Low visibility could make driving conditions hazardous," adds the weather service. "If driving, slow down, use your headlights, and leave plenty of distance ahead of you."

Guidance from the weather service for navigating foggy conditions

If a dense fog advisory is issued for your area, it means that widespread dense fog has developed and visibility often drops to just a quarter-mile or less. These conditions can make driving challenging, so exercise extreme caution on the road, and if possible, consider delaying your trip.

If driving through fo

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