Frost/Freeze — W Central S.j. Valley, California

2018-12-29 to 2018-12-30 · W Central S.j. Valley, California

Event narrative

Several locations reported minimum temperatures between 28 and 32 degrees on December 29 and December 30.

Wider weather episode

A cold and dry northerly flow aloft prevailed over Central California ahead of an offshore upper ridge. This resulted in strong radiational cooling taking place in the San Joaquin Valley on the mornings of December 29 and December 30 with the dry low level air resulting inhibiting fog formation. As result, temperatures dropped below the freezing mark across much of the San Joaquin Valley on both mornings resulting in this being the first widespread freeze of the season in the valley.

Source: NOAA Storm Events Database, event_id 791312. Narrative written by the NWS forecast office that issued the report.