Scattered rain/snow showers possible today, mainly over the foothills and mountains. Dry weather expected Sunday into next week with above normal daytime temperatures and some locally gusty north to east wind.
Discussion
540 DM upper low centered near KRNO this morning is progged to move down the Sierra Nevada, pushing into southern Nevada this afternoon. Secondary embedded vort lobe swings across interior NorCal this morning into the afternoon. This will keep a threat of showers today, with highest POPs over the eastern foothills and mountains. Mesowest data showing snow levels around 2000 feet attm, so potential for some light snow accumulations in the upper foothills this morning.
Models suggest that by the afternoon, showers (snow) will be confined to the Sierra Nevada with precip threat ending this evening. Heights begin to rise over interior NorCal tonight into Sunday as EPAC upper ridge begins to build inland with northerly flow aloft.
Areas of frost possible in the Central Valley tonight as skies clear, dewpoints lower, and longwave radiational cooling drops the mercury into the low to mid 30s.
Low level pressure gradient increases tonight into Sunday as surface high pressure builds through OR into the Great Basin. Dry weather expected tomorrow with high temperatures near to slightly above normal.
Warming trend expected Monday into Tuesday as heights/thicknesses continue to increase over interior NorCal. High temperatures in the Central Valley climb into the upper 60s to lower 70s Monday, then low to mid 70s Tuesday. Periods of locally gusty north to east wind possible.
Extended Discussion (Wednesday through Saturday)
After a mild day on Tue, the EFP continues to suggest some cooling Wed and Thu from the Wrn Canadian/B.C. short wave as it drops Swd into the Pac NW. Eventually this system carves out a long wave trof that will impact the Rockies and Ern parts of NOAM late next week.
The 5H Cluster Analysis suggests a little retrogression of the amplified and persistent Ern Pac ridge which will allow some cooler Canadian air to infiltrate NorCal during this time along with periods of gusty N to E winds. The ECMWF is farther W than the GFS in spreading modified arctic air into the Nrn and Ern portions of NorCal affecting/biasing the Cluster Analysis with the larger number of members for each Cluster. Mainly relied on the WPC guidance as the optimum blend of the two extremes.
Regardless of model preference the precip is expected to remain N and E of our CWA, although the ECMWF would possibly brush our extreme NErn zones (Burney/Lassen NP areas) with at least a chance of some light precip. The Ern Pac ridge re-establishes itself for a modification of temps on Fri. NorCal may be on the Srn or tail end of a wx system moving through the Pac NW late next weekend.