322
FXUS66 KSTO 121056
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
256 AM PST Thu Nov 12 2026
.KEY MESSAGES...
- Dry weather, above normal temperatures, and periodically
breezy north to east winds through Thursday
- A series of storm systems will bring widespread rain, moderate
to heavy rain and snow in the mountains, and gusty to strong
southerly winds Friday into early next week
- Winter Storm Watch in effect from Friday morning through Monday
afternoon for the Sierra and Lassen National Park above 6000`
- Wind Advisory is in effect from 4 am to 7 pm PST Friday for
the northern Sacramento Valley and portions of the central
Sacramento Valley
&&
.DISCUSSION...
...Today through Thursday...
A ridge till continue to remain in place across the area today
into tomorrow, but slowly break down and shift east late Thursday.
Dry conditions are expected with temperatures above normal across
the area. Highs will be in the 70s across the area, with cooler
conditions at the higher terrain. Breezy conditions at times
within the higher terrain especially in the gaps and valleys.
Potential for lower ceilings and patchy fog during the morning
hours on Thursday as dew point depressions near zero across parts
of the southern Sacramento Valley into the northern San Joaquin
Valley. Visibility reductions to a couple miles will be possible
at times especially near waterways. Winds will start to pick up
late on Thursday and into the early morning hours on Friday as a
trough digs into the southwestern United States.
...Friday and Saturday...
The first of several storm systems moves into the region Friday
through Saturday bringing mountain snow, rain, thunderstorms and
windy conditions to the region. Rain will overspread the region
Friday morning and coverage will only increase as we move
throughout the day. Heavy rainfall rates are possible with
stronger thunderstorms that develop in the afternoon and evening
hours. Coverage of rain and thunderstorms starts to diminish in
the overnight hours, with isolated to scattered chances within the
mountains and isolated within the Valley. Total forecasted
rainfall will be 0.25 to 1 inch within the Valley, up to 2 inches
within the mountains and foothills. Isolated higher amounts are
possible especially where stronger storms develop. Latest HIRES
guidance has the slight potential for a SCCZ developing during the
evening hours on Friday. However, confidence is low on placement,
duration, development, and how long one may set up.
Increased low level moisture, instability, and wind shear will
help develop a few thunderstorms across the Valley/Foothills
during the afternoon and evening hours. A few storms may be on the
stronger side as noted within atmospheric soundings across the
Valley/Foothills. Strong elongated shear, instability up to 400
J/kg, and synoptic support will help initiate thunderstorms for
the Valley/Foothills as the system moves onshore across the area.
Impacts from stronger storms would be heavy rainfall rates,
frequent lightning, gusty winds, and small hail.
On top of the rain and thunderstorm chances will be the strong
southerly winds that develop during the morning and afternoon
hours on Friday. A Wind Advisory is in effect for parts of the
northern Sacramento Valley and central Sacramento Valley from 4am
Friday through 7pm Friday due to the strong southerly winds. Gusts
up to 45 mph are expected within the Advisory area, with up to
35 mph elsewhere. Strong winds within the mountains as well. There
is a chance for an extension to the Advisory to incorporate the
southern SAcramento Valley and into parts of the Delta, but
confidence is low on how strong winds will be within those areas
for Friday. Right now probabilities to see above 40mph wind gusts
are 40 percent within the Delta and 30 percent within the
southern Sacramento Valley. We will continue to monitor the need
for any extension on Friday to incorporate the southern Sac
Valley and into the Delta.
Now for the snow chances within the higher terrain, snow levels
continue to trend lower. Snow levels will be 6500-7500 ft Friday
and drop to 5500-6500 feet by Saturday morning. Snow will be heavy
at times, with strong winds creating potential white out
conditions. Travel could be very difficult during this time
impacting the Friday evening and Saturday commutes. A lull in
activity is expected Saturday afternoon and evening as the first
system moves out of the region and the second moves into CA
Saturday night.
...Sunday and Beyond...
Lull in activity is expected Saturday afternoon/evening, with the
secondary system moving in Saturday night in Sunday. Precipitation
coverage becomes widespread once again across the area Sunday
throughout the day. A slight chance for an afternoon thunderstorm
is possible, but instability is on the lower end along with shear
at this time. Rainfall may be moderate at times within the
mountains, foothills, and Valley. Coverage will start to diminish
along with rain intensity as we move into Monday. The Valley
precip chances start to clear out slowly by the late afternoon and
evening, with lingering precipitation in the mountains through
Tuesday morning. Up to 2 inches of QPF will be possible within
the higher terrain Sunday through Tuesday morning. Areas within
the Valley will see up to an inch of QPF.
Snow levels during this time will be in the 6500-7500 feet Sunday
afternoon and drop to 5500-6500 feet Monday morning. Snow will be
heavy at times, with reductions to visibility. Travel may be very
difficult for the Monday commutes. Looking at both systems
together, up to 2 feet will be possible at higher peaks from
Friday through Monday. Minor accumulations of up to an inch are
possible down at 5000 feet. A Winter Storm Watch is in effect
from Friday morning through Monday afternoon for the northern
Sierra above 6000 feet, including Highway 50, I-80, the southern
Cascades, and Lassen National Park.
Another lull in activity is expected Tuesday morning and
afternoon, with the potential for the active pattern to continue.
There is a potential for further systems mid to late next week
bringing more precipitation to the area. Uncertainty arises with
the timing, development, and strength of these systems.
&&
.AVIATION...
VFR conditions are expected through the TAF period, with locally
MVFR around the Sacramento Sites and SCK 12z through 17z for low
ceilings and visibility. Surface winds will remain light and
variable across the Valley today. Otherwise, skies will be mostly
clear today, with increasing high clouds in the afternoon. Late
tonight and Friday, light to moderate rain and gusty winds is
expected as a frontal boundary moves through.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 4 AM to 7 PM PST Friday for Butte County
Below 1000 ft-C. Solano County including Fairfield-Central Glenn
Co & Interstate 5-Eastern Glenn County-N. Sac Valley in Tehama
County-SW Solano County including Vallejo-Shasta Metro.
Winter Storm Warning from 10 AM Friday to 10 AM PST Saturday for
Lassen Volcanic NP-Sierra (Cal-Tuo) Above 5000 ft-Sierra (El
Dorado-Amador) Above 5000 ft-Sierra (Sierra-Placer) Above 5000
ft.
&&
$$
