Sunny and warm weekend will morph into wet and wintry week

January 13, 2018 – Dry this weekend with night and morning valley fog. Periods of precipitation Monday through Friday.

Discussion

Dry weather prevails over the weekend as Interior NorCal under the influence of strong upper ridging. Areas of fog have developed in the Central Valley overnight from about KOVE southward. Some areas which had dense fog earlier, the fog has lifted into a low stratus deck. If this trend continues, may need to drop the Dense Fog Advisory as visibility will likely be above a quarter of a mile in most areas. Stratus likely to persist again through midday in portions of the Central Valley. Highs forecast to be above normal this afternoon with upper 50s to upper 60s in the Central Valley, and 40s to low 60s for the foothills and mountains. Little change expected Sunday with night and morning valley fog again and max temps remaining above normal.

Models showing a wetter pattern setting up next week however differences exist with timing of the systems. GFS spreads pre-frontal precip over the forecast area Monday, while the EC is more towards Monday night. Front then forecast to move through Tuesday bringing widespread rain and higher elevation snow. Snow levels will lower below pass levels Tuesday into Tuesday night however accumulation look to be light at this time.

Extended discussion (Wednesday through Saturday)

Short-wave ridging in the wake of the early-week system will result in mostly dry weather across the region on Wednesday. There continues to be good agreement in the latest GFS and EC runs with another system moving into NorCal Thursday followed by lingering showers on Friday. Moderate amounts of precipitation are expected and lower snow levels may result in some travel impacts over the mountains. Another system lurks for late next weekend.