August 23, 2016 – Continued warm and dry. A subtle warm up expected Wednesday and Thursday, but still around seasonal averages.
Skies are clear across interior NorCal early this morning except for some lingering clouds across the far southeast corner of the forecast area. The marine layer remains around 1500-2000 feet deep and onshore flow continues. Temperatures are a little cooler across most of the area compared to 24 hours ago and generally range from the 40s in the mountain valleys to the upper 50s to around 70 in the valley.
Persistent weak upper trough will continue relatively temperate pattern across the region through the remainder of the week, though highs are expected to bump up a bit on Wednesday and Thursday as onshore flow slackens for a day or so. Deeper moisture and instability, and thunderstorm chances, will be east and south of the area for the remainder of the week.
Extended discussion (Saturday through Tuesday)
Upper low/trough off the West Coast over the weekend is progged to progress across NorCal Monday or Tuesday. Models differ on when it moves through with GFS about 24 hours faster than the ECMWF. In either case, available moisture is limited and main impact appears to be increased onshore flow with some synoptic cooling. Below normal temperatures are expected through the extended forecast period with 80s to lower 90s in the Central Valley with 60s to 80s for the mountains and foothills.