712
FXUS66 KSTO 131028
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
228 AM PST Fri Nov 13 2026
.KEY MESSAGES...
- A pair of storm systems will bring widespread rain, moderate
to heavy rain and snow in the mountains, and gusty to strong
southerly winds today into Monday
- The first storm begins today and continues into early Saturday
and will be the stronger system in terms of winds and heavy
snow. After a lull during the day Saturday, the second storm
arrives Sunday and continues into Monday
- Winter Storm Warning in effect from 10 AM PST this morning
through 10 AM Saturday morning for the Sierra and Lassen
Volcanic National Park above 6000`
- Wind Advisory is in effect from 4 am to 7 pm PST today for the
Sacramento Valley and Delta
- Flood Advisory until 4 PM this evening for low-lying areas
along the Delta and vicinity, with coastal flooding potential
from high tides
- Another storm will bring the potential for additional rain,
mountain snow and gusty winds mid to late next week
&&
.DISCUSSION...
...Today-Saturday...
The first of several storm systems moves into the region today
and continues through Saturday morning bringing moderate to heavy
mountain snow, widespread rain, thunderstorms and windy
conditions to the region. Rain is gradually moving into the area
and will spread across the region this morning and coverage will
only increase as we move throughout the day. Heavy rainfall rates
are possible with stronger thunderstorms. Latest CAMS models are
showing potential for a line of thunderstorms in the morning, with
additional potential in the afternoon and early evening hours.
Coverage of rain starts to diminish in the overnight hours, with
isolated to scattered chances within the mountains and isolated
within the Valley. Total forecast rainfall with this first storm
is 0.25" to 0.75" in the Valley and Delta, up to nearly 3 inches
in the mountains and foothills. Isolated higher amounts are
possible especially where stronger thunderstorms develop. The
latest NBM shows a 10-15% Chance of thunderstorms this morning, a
15-25% chance of thunderstorm development this afternoon and
evening. There is quite a bit of shear, both low and mid level, so
there is some potential for severe storms. Impacts from stronger
storms would be heavy rainfall rates with ponding of water on
roads, frequent lightning, gusty winds, and small hail, as well as
gusty winds.
In addition to gusty winds possible with thunderstorms there will
be strong southerly winds that peak later this morning and
early afternoon. Winds were already beginning to increase over
the northern Sacramento Valley early this morning, with gusts to
25 to 35 mph by 2 AM PST. A Wind Advisory is in effect for the
Sacramento Valley and Delta from 4 AM this morning through 7 PM
this evening. Gusts up to 35-45 mph are expected within the
Advisory area, with the strongest winds expected over the northern
Sacramento Valley. There is even a locally 60-80% chance of winds
greater than 45 mph in the vicinity of Red Bluff and just to the
east. Strong winds are expected over the mountains as well, with
gusts up to 60 mph. Downed tree branches and localized power
outages are possible.
Mountain snow will be heavy at times above 6000 feet, combining
with the strong winds to create significant reductions in
visibility, with near whiteout conditions possible. Travel could
be difficult during this time, impacting mountain travel this
evening and into early Saturday. Total snow accumulations of 6 to
12 inches are expected, with up to 18 inches at the highest
peaks. Minor accumulations of up to an inch are possible down at
5000 feet. The heaviest snow is expected late this morning into
the evening hours, with a period of heavy snow with intensity to
around 2" an hour at times, when associated with convective
storms. Snow levels will be 6500-7500 ft today and drop to
5500-6000 feet by Saturday morning. A Winter Storm Warning remains
in effect from 4 AM this morning through 10 AM Saturday for the
northern Sierra above 6000 feet, including Highway 50, I-80, the
southern Cascades, and Lassen Volcanic National Park. A lull in
activity is expected Saturday afternoon and evening as the first
system moves out of the region, with mainly just some lingering
showers.
A Flood Advisory remains in effect until 4 PM this evening for
low-lying areas along the San Pablo Bay, Carquinez Strait, and
Suisun Bay shorelines in Solano County, as well as low-lying areas
along the Sacramento River, San Joaquin River, and other Delta
waterways. This is due to the potential for coastal flooding from
high tides.
...Sunday and Beyond...
A lull in activity is expected Saturday afternoon/evening, with
storm number 2 moving in Sunday and continuing into Monday.
Precipitation spreads into the west in the morning with coverage
becoming widespread by Sunday afternoon. 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. Precipitation chances in the Valley start to clear by the
afternoon and evening, with lingering precipitation in the
mountains ending early Tuesday morning. WPC guidance has trended
slightly lower, indicating precipitation amounts ranging from
0.25 to 1 inch in the Valley, with 0.75" to 1.75" over higher
terrain. Snow levels during this time will around 6500-7500 feet
Sunday afternoon and drop to around 5500-6500 feet Monday morning.
Snow will be moderate at times and snow totals are expected to be
less with this second storm, with a 50-75% chance of seeing at
least 6 inches of snow over the Sierra (highest chances south of
Highway 50). Heaviest snow is expected late Sunday night into
early Monday morning. Slippery roads as well as some reductions
in visibility are possible at times, bringing travel delays.
Another lull in activity is expected Tuesday morning and
afternoon. There is a potential for an additional system mid to
late next week bringing more precipitation to the area. While
uncertainty continues with the timing, development, and strength
of these systems, recent trends are showing potential for another
wet system with widespread rain, impactful mountain snow and gusty
winds. Stay tuned to see how the forecast develops!
&&
.AVIATION...
Predominantly VFR conditions are expected over the next 24 hours
with periods of MVFR in lowered visibility from moderate to heavy
rain. South winds increase with gusts 25 to 35 kts in the Valley
today, with isolated gusts to 40 kts. Winds will gradually weaken
after 03Z Saturday. In addition to gusty south winds, a storm
system will bring showers, mountain snow above 6000 feet, and
chances for isolated thunderstorms on Friday. These may result in
brief periods of IFR/LIFR at times, as well as gusty erratic
outflow winds and small hail.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM PST this evening for Butte County Below
1000 ft-C. Solano County including Fairfield-C. Yolo/NE Solano
including Woodland-Central Colusa County Incl. I-5-Central Glenn
Co & Interstate 5-Eastern Colusa County-Eastern Glenn County-N.
Sac Valley in Tehama County-SW Solano County including Vallejo-
Sac Metro/W. El Dorado/Amador County-Shasta Metro-Sutter/Yuba
counties below 1000 ft-W. Yolo County including Capay/I-505.
Winter Storm Warning from 10 AM this morning 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.
&&
$$
