White Rock, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

694
FXUS66 KSTO 261108
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
308 AM PST Thu Dec 26 2024



.SYNOPSIS...
Active weather will bring rain, mountain snow, and breezy to
gusty southerly winds today into the weekend. Drier weather
anticipated early next week.

&&

.DISCUSSION...
Mostly cloudy skies and gusty winds are being observed across
interior Northern California with current temperatures in the
40s-50s in the Valley/foothills and 20s-30s in the mountains.
Scattered showers are bringing light rain to portions of the
northern Sacramento Valley early this morning as the first
shortwave in a series of weather systems moves through NorCal.

The moisture with this first wave will be focused further
northward, with the majority of accumulating precipitation
expected north of I-80. Current probabilities of exceeding 0.5
inches of rain sit around 70% to 95% across the northern
Sacramento Valley and surrounding terrain and along the
Sierra/southern Cascades from I-80 northward, falling to 20% to
40% probabilities south of Interstate 80. Current ensemble trends
indicate a 3-6 hour break between systems This evening with the
next shortwave progressing through interior NorCal overnight
tonight into Friday. The associated moisture plume is projected to
take a slightly further southward trajectory, resulting in a
better opportunity for more widespread precipitation on Friday.
Resultant probabilities of rain exceeding 0.5 inches increases to
30% to 60% across the Delta, southern/central Sacramento Valley,
and northern San Joaquin Valley, with 60% to 80% probabilities of
exceeding 1 inch across the northern Sacramento Valley and
surrounding terrain and along the Sierra/southern Cascades.

Today, snow levels will be 5000 to 6000 feet, before rising to
7000-8000 in Friday. Current probabilities of snowfall exceeding 6
inches through midday Friday sit around 40% to 70% above 6000
feet at this time. As a result, a Winter Weather Advisory remains
in effect until noon on Friday, with mountain travel impacts
anticipated. Additionally, southerly winds are expected to gust 20
to 40 mph with the strongest winds from Yuba City to Red Bluff.

The active weather period then continues across interior NorCal
into the weekend underneath broad northwesterly flow aloft. This
flow pattern will allow another shortwave ejection, similar to
today`s system, into the region. As a result, the majority of
precipitation on Saturday is expected from Interstate 80 northward
at this time. Attendant probabilities of exceeding 0.5 inches of
liquid precipitation around 60% to 80% favor the northern
Sacramento Valley and surrounding terrain and the Sierra/southern
Cascades north of I-80, with probabilities generally less than
20%. elsewhere. Given high expected snow levels above 8000 feet,
only light accumulations at peaks are expected on Saturday.

On Sunday, ensemble PWAT anomaly shows another push of moisture
reinvigorating Saturday`s system bringing yet more rain and colder
air. Snow levels will initially sit around 6000-7000 feet before
lowering that afternoon to 5000 to 6000 feet Sunday afternoon.
Currently there is a 20 to 40% chance of snow accumulations
exceeding 4.00 inches. Highest rainfall accumulations will once
again be over Shasta County and the foothills/mountains with a 50
to 90% chance of 0.5" or more on Sunday. Lower probabilities over
the Valley with a 30 to 50% chance of 0.5" or more of rainfall
north of I-80. Sunday will also bring a 10 to 20% chance of
isolated thunderstorms over the Valley and Sierra Nevada
foothills/mountains.

Please continue to check weather.gov/sto for the latest updates
and check quickmap.dot.ca.gov before you travel!


.EXTENDED DISCUSSION (Monday THROUGH Thursday)...
Models showing interior NorCal will be under the influence of
upper level ridging through the extended forecast period. High
temperatures will be near to slightly above normal with chilly
nights. Potential for some patchy overnight fog or frost in the
Central Valley. NBM showing potential for some precip over
northern portions of the CWA Wednesday into Thursday, however
confidence in this is low given progged synoptic pattern.

&&

.AVIATION...
Areas MVFR/IFR with lcl LIFR over mtns, obscuring trrn. possible
today in precip, becoming more widespread aft 03z Fri. Snow levels
5500-6500 ft rising to 7000-8000 ft aft 06z Fri. Areas Sly sfc
wind 15-20 kts in Sac Vly til 20z Thu. Widespread Sly sfc wind
15-25 kts with areas of gusts to 35 kts in Central Vly aft 05z
Fri. Over mtns, areas S-W sfc wind gusts 30-40 kts increasing to
35-50 kts aft 06z Fri.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon PST Friday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

$$