776
FXUS66 KSTO 111048
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
248 AM PST Wed Nov 11 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
- Blizzard conditions expected for elevations above 7000` on
Friday, creating dangerous and potentially impossible travel
- 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-Saturday:
Quiet weather conditions prevail across interior NorCal through
Thursday, with dry and warm conditions along some north to east
winds at times. Expect mostly sunny day and seasonably mild
temperatures, with highs 5 to 10 degrees above normal. On
Thursday, high level clouds are expected to increase throughout
the day. South winds are also expected to increase across the
area, with breezier conditions over the northeastern Foothills.
Wet and unsettled weather returns late Thursday/Friday and will
continue through early next week as a series of shortwave trough
along with a round of subtropical moisture plume impact the region
with periods of moderate to heavy rain, heavy mountain snow, and
breezy to strong south winds.
The first system is expected to arrives Thursday night/Friday,
with an associated frontal boundary along with subtropical
moisture plume spreading widespread precipitation by mid- day
Friday. A frontal boundary will bring increasing southerly winds
late Thursday night, and peak up on Friday. It will be more
unstable and strong winds aloft Friday afternoon/evening most
likely mix down to the surface, especially near or along the
surface front. Gusts up to 45 mph is expected over the northern
Sacramento Valley, with 45 to 60 mph across the Sierra. While
gusts to 30 to 40 mph are forecast for much of the rest of the
Valley and Delta. However, there is a 30 to 50% chance of wind
gusts exceeding 45 mph across the Delta. Wind Advisory remain in
effect from 4 AM Friday to 7 PM Friday for Northern Sacramento
Valley and portions of the central Sacramento Valley. If the
increasing wind trend continues, the Delta and Valley areas north
of I-80 and along the I-5 should be consider by the day shift to
be included in the Wind Advisory.
A period of moderate to heavy rainfall is expected Friday
afternoon into Saturday, with the heaviest rain on Friday
afternoon and evening. Forecast rainfall totals for that period
ranging from 1-3" for the mountains, 0.4-1" in the Valley and
Delta. There is also the potential for isolated thunderstorms
Friday afternoon and evening, with a 10-25% probability in the
afternoon, highest in the mountains and foothills north of I-80.
With a relatively slow start to the water year, the ground is not
saturated and rivers/streams are relatively low, which help to
mitigate flood concerns, but locally heavy rain could cause local
flooding, mainly ponding on roads with clogged drains.
Anyone with weekend mountain travel should be sure to stay up to
date with the latest forecast information as confidence in winter
weather impacts have increased, with a Winter Storm Watch now in
effect Friday morning through Monday afternoon. The potential for
moderate to heavy snow continue to increases Friday afternoon,
peaking in the evening and overnight. Snow levels start around
7000-8000`, dropping to 5500-6500` Saturday morning. There is a
50-90% chance of 12" of snow for the Sierra and around the Lassen
Volcanic National Park area above 6500 feet through 4 am Saturday.
There is currently a lull period of lighter snow during the day
Saturday, but model fluctuations make confidence in this timing
currently low.
Conditions will gradually improve throughout the day on Saturday,
with lingering showers through Saturday evening/night.
Sunday through Tuesday:
A second system is expected to move in Saturday night through
Monday, with another period of moderate to heavy rainfall and
mountain snow. Snow levels are expected to drop to around 5000
feet. Snow totals of around a foot are expected through both
systems, with up to 2 feet over higher peaks. Additional rainfall
amounts of 0.75 to 1.5 inches is most likely for the mountains,
with up to 1.5 inch over the northern Sacramento Valley. Up to
half of an inch is expected for the rest of the Valley and Delta.
&&
.AVIATION...
Mainly VFR conditions at TAF sites, with local MVFR/IFR
visibility reductions in BR for the northern San Joaquin Valley
possible from 10Z through 15z. Light and variable winds persist
across the forecast period at TAF sites.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 4 AM to 7 PM PST Friday for Butte County
Below 1000 ft-Central Glenn Co & Interstate 5-Eastern Glenn
County-N. Sac Valley in Tehama County-Shasta Metro.
Winter Storm Watch from Friday morning through Monday afternoon
for Lassen Volcanic NP-Sierra (Cal-Tuo) Above 5000 ft-Sierra (El
Dorado-Amador) Above 5000 ft-Sierra (Sierra-Placer) Above 5000
ft.
&&
$$
