Dense Fog — E Central S.j. Valley, California

2018-12-19 to 2018-12-20 · E Central S.j. Valley, California

Event narrative

Visibility below a quarter mile was reported in Merced and Atwater. Several school districts opened late or delayed bus service.

Wider weather episode

A strong upper ridge was centered over California on the morning of December 20. With clear skies, light winds and inversion conditions all present, an area dense fog formed over the San Joaquin Valley from south of Fresno to north of Wasco. Several observations of visibility below an eighth of a mile were reported by airport equipment or by law enforcement, and as a result of the dense fog, traffic was paced on some of the major highways and several school districts either had delayed openings or delayed bus service. The fog finally lifted by late morning and visibility improved during the afternoon.

Source: NOAA Storm Events Database, event_id 790646. Narrative written by the NWS forecast office that issued the report.