January 2, 2019 – Dry with chilly nights and near normal daytime temperatures. Wet weather returning this weekend through at least the middle of next week with mountain travel impacts likely.
Short term forecast starts out dry under a high pressure ridge over the west coast. Fair skies this morning with lighter winds than 24 hours ago allowing much cooler early morning temperatures most locations. The delta region has especially shown this cooling with current temperatures dropping into the upper teens. Temperatures should warm up today reaching maxes just a bit above normal although lighter winds should make it feel a little warmer. Another cool clear night tonight followed by another dry Thursday with highs remaining a little above normal.
High clouds spilling over the ridge and into NorCal Thursday afternoon will, however, indicate changes in the weather pattern ahead as the upper ridge begins to break down and shift east of the state. Friday should remain mainly dry as a weak frontal band moves into the Pacific Northwest with increased high cloud cover and southerly winds.
Precipitation with this system will likely remain north of the forecast area. A stronger Pacific frontal system off the NorCal coast will bring the first round of significant precipitation to the north state Friday night and Saturday as a Pacific cold front pushes through. Models are in fairly good agreement on all areas of the CWA seeing at least some some precipitation. With snow levels well below pass levels, precipitation should be significant enough to create travel difficulties over the Sierra.
Extended Discussion (Sunday through Wednesday)
The remnants of Saturday`s storm system will linger over northern California on Sunday with a secondary system trailing behind it. Models differ with the timing of this secondary system with the GFS pushing it through on Sunday while the ECMWF is slower has it come through on Monday and keeps showers over the area instead.
Regardless, the models continue to keep the wet pattern over NorCal through the week. There may be a brief dry period on Tuesday, but there is a chance of lingering showers depending on which model pans out. Beyond that, models struggle with the timing of additional disturbances bringing precip to the area.