August 6, 2020 – Warming trend through the weekend, turning above normal by Saturday. A slight chance of mountain thunderstorms from Friday into early next week.
Discussion
Upper trough continues over NorCal today, although onshore flow will weaken allowing for warmer, but still slightly below normal temperatures today. Highs will be in the upper 80’s over the Cent/Southern Sacramento Valley, Northern San Joaquin Valley and Delta and low 90’s Northern Sacramento Valley.
Weak low splits off main flow near the Bay Area Friday, as main jet flow relocates over the Pacific Northwest. This low will bring just enough moisture northward over the Sierra for a few isolated thunderstorms near the crest mainly south of Interstate 80. Low drops south off the SoCal coast Saturday with isolated mountain thunderstorm chances shifting a bit south, mainly south of Highway 50.
Rising heights and diminishing onshore flow into the weekend will allow temperatures to warm to near normal levels Friday then slightly above normal Saturday. Highs Saturday will be 95 to 105, warmest Northern Sacramento Valley.
Extended Discussion (Monday through Thursday)
Broad trough pattern to continue offshore of the West Coast for much of the upcoming week. Temperatures should cool to near normal levels, as at least weak periods of onshore flow continues. Also cannot rule out a few isolated thunderstorms near the crest Monday and Tuesday in weak upper level Col region. Westerly flow is forecast to increase by mid-week which should push moisture east of the area.