April 6, 2020 – Cool and unsettled weather continues today with scattered showers and a few thunderstorms. Dry and milder weather returns Tuesday and continues through the remainder of the week.
Discussion
Satellite imagery shows the deep closed low off the coast of NorCal early this morning with a couple of strong vorts rotating in its midst – one to the southwest of the Bay Area and a second to the west of Cape Mendocino. Skies have cleared out across portions of the Sacramento Valley while radar indicates tapering snow over the northern Sierra Nevada along some showers over the northern Sacramento Valley and northern San Joaquin Valley.
The deep low will move slowly southward off the coast today. Lingering precipitation is expected to continue to taper off early this morning, but scattered showers and thunderstorms will redevelop by late morning and through the afternoon as instability builds with daytime heating. The main area of activity is expected over the southern half of the forecast area as the strong vort southwest of the Bay Area pivots onshore. Main threat today from stronger storms will likely be copious amounts of small hail as forecast soundings indicate deep, but skinny CAPE and weak shear.
Some lingering wrap-around showers will be possible across the NorCal mountains on Tuesday and Wednesday as the low moves into SoCal. The remainder of the forecast area will see a return of dry weather, and temperatures will return to above average by Wednesday.
Extended Discussion (Friday through Monday)
The slow moving upper low from earlier in the week will continue to be stubborn in exiting the state. By Friday morning, some of the guidance keeps the circulation over the southern California deserts. However, any impacts will be long gone as heights continue to be build in the wake. The strengthening ridge should easily bolster temperatures well into the 70s over the Valley with even some lows 80s squezing into the northern Sacramento Valley. Overall, expect daily highs to run around 5 to 10 degrees above average accompanied by mostly sunny skies and relatively light winds.