Marine Weather and Tide Forecast for Oakdale, CA

DISCUSSION
As of early this morning, aside from some scattered cirrus drifting across the region, generally calm weather is being observed. Despite this, a notable shift in the upper level pattern is beginning to take shape as persistent ridging aloft is weakening at the moment. In the interim, dry weather, light winds, and seasonable temperatures look to prevail much of today across interior NorCal, with any appreciable changes beginning late tonight. Given the transitional period expected today, high temperatures in the low to mid 60s are anticipated across the Delta, Valley, and foothills, with 50s at higher elevations and some scattered cloud cover likely lingering as troughing builds in.

As large scale troughing digs across interior Canada today, broad ridging looks to enforce itself over the southern US, which will prime the west coast for a period of more active weather into the weekend. Current ensemble trends continue to indicate that the combination of these evolving weather patterns aloft will culminate in a separate lobe of the aforementioned trough retrograding southwestward toward California late today into the weekend. While attendant available moisture will be limited, especially across interior NorCal, some northward moisture advection is anticipated as the system progresses.

As a result, some light precipitation is anticipated on Saturday and possibly lingering into Sunday, but is generally expected to remain limited to the Sierra and adjacent foothills from Interstate 80 southward. The notable deepening of this trough will allow snow levels to drop to around 2000 to 3000 feet by Saturday, and even as low as 1000 to 2000 feet by Sunday morning.
While some flurries and light accumulations under an inch will be possible into some foothills locations, the overall lack of appreciable moisture is expected to keep the majority of accumulating snowfall above 5000 feet at this time. Resultant probabilities of snowfall exceeding 3 inches through Sunday sit around 30 percent to 60 percent above 5000 feet from Interstate 80 southward, with highest probabilities currently favored south of the Highway 50 corridor.

With precipitation potential remaining somewhat limited even with the trough deepening as it retrogrades, increasing north to east winds are expected to provide additional impacts across interior NorCal. While some uncertainty regarding timing and exact trajectory of the system between ensemble suites persists, consensus at this time indicates winds beginning to increase tonight. Even with some nuanced timing uncertainty, strongest winds are expected to occur on Saturday, with still gusty winds lingering into Sunday morning as well. Current probabilities of wind gusts exceeding 40 mph are sitting around 70 percent to 90 percent from Interstate 80 northward, with even some pockets of 20 percent to 40 percent probabilities of wind gusts up to 50 mph across typically higher wind prone areas of the northern and central Sacramento Valley. As a result, a Wind Advisory remains in place from 10 PM tonight through 10 AM Sunday across portions of the northern and central Sacramento Valley and adjacent foothills/mountain locations.

While the trough looks to become quasi-stationary on Sunday, an amplifying ridge building into the Pacific Northwest is expected to gradually push the the trough out of interior NorCal into early next week. North to east winds will likely remain breezy through Sunday, becoming lighter into Monday as the ridging influence becomes more prominent. The general interactions between the departing trough and building ridge is currently resulting in some forecast uncertainty into next week, but an overall trend toward drier and calmer weather is anticipated. Along with this pattern shift, slightly below to near normal temperatures are expected, with potential for a few cold mornings looking likely across interior NorCal as well.

.EXTENDED DISCUSSION (Tuesday THROUGH Friday)...
EPAC upper ridging forecast to progress through interior NorCal Tuesday into Wednesday. Dry weather expected with lighter wind and near normal high temperatures. Weak Pacific frontal system progged to move into the CWA Thursday, with model differences in timing. Some light QPF being advertised. NBM increases POPs over entire CWA Friday, however confidence is low with this as deterministic models showing less potential for precip.

AVIATION
Isolated MVFR/IFR in BR possible in S Sac/N San Joaquin Vlys til 17z, otherwise VFR conditions over interior NorCal thru 12z Sat.
Sfc wind mainly below 12 kts til 06z Sat, then areas of N-NE sfc wind 15-25 kts N of I-80.

STO WATCHES/WARNINGS/ADVISORIES
Wind Advisory from 10 PM this evening to 10 AM PST Sunday for Central Sacramento Valley-Mountains Southwestern Shasta County to Western Colusa County-Northeast Foothills/Sacramento Valley- Northern Sacramento Valley-Shasta Lake Area / Northern Shasta County-Southern Sacramento Valley-West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park.