December 26, 2018 – Mainly dry through end of the week except isolated mountain showers Thursday. Chance of light showers northern mountains Sunday. Breezy north wind Thursday and early next week.
Discussion
Upper ridge over the west coast bringing dry conditions to the forecast area with just some high clouds spilling over into norcal this morning. A light northerly surface gradient is producing light northerly breezes down the central valley this morning and this has kept fog from forming anywhere down the valley. Fair skies and dry conditions will allow for another day of above normal daytime temperatures. An upper low dropping through the Pacific northwest and into the Great Basin tonight and Thursday will bring a slight threat of mountain crest showers northern and Sierra crest mountains. Surface high pressure pushing in to the Pacific Northwest behind this system will bring a stronger northerly surface gradient by Thursday afternoon. This will bring fairly breezy north winds down the central valley and over the mountains Thursday afternoon and night. Northerly breezes will keep fog out of the valley again Thursday night and Friday morning. Breezy north winds continue into Friday with daytime highs remaining above normal. Upper ridge axis forecast to center over the west coast on Saturday. This will bring decreasing winds, fair skies, and continued above normal temperatures going in to the weekend.
Extended Discussion (Sunday through Wednesday)
The extended forecast looks mainly dry, with forecast high temperatures a little above normal and low temperatures a few degrees below normal.
The latest European model continues to shows trough passing through the Pacific Northwest and brushing through far Northern California on Sunday, while the GFS keeps it further north. For now, will keep a slight chance of light showers over the southern Cascades. Most of the area will remain dry even in this scenario, though.
Upper level ridging with northerly flow will keep the weather dry through the middle of next week. Breezy northerly winds are possible at times.