Air quality is unhealthier-than-average for some people Thursday as winds are blowing wildfire smoke across the Northern California region.

An air quality advisory is in effect for the Bay Area on Friday, as smoke from wildfires burning in far Northern California drifts into the region.

With smoke drifting over the Sacramento region from wildfires in the north state, air quality officials are urging capital residents to minimize pollution Friday, the summer's first "Spare the Air" day.

The National Weather Service in Reno said the smoke is being driven by a slow-moving northerly flow aloft and is expected to linger through the day. Satellite imagery Thursday morning showed thick plumes stretching across northwest Nevada and the Sierra.