321
FXUS66 KSTO 150913
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
113 AM PST Sun Nov 15 2026

.KEY MESSAGES...

 - A storm system arrives today bringing widespread
   Valley/Foothill rain, mountain snow, and breezy southerly winds
   through Monday; not as impactful as recent system.

 - Winter Weather Advisory in effect from 4 PM today through 10
   PM Monday for the Sierra and Lassen Volcanic National Park
   above 6000 feet.

 - Colder, and much wetter weather storm system mid to late week
   will bring widespread rain, heavy mountain snow, and strong,
   gusty southerly winds.

&&

.DISCUSSION...

...Today through Monday...
The next system moves into the area today, bringing widespread
rain and breezy southerly winds. Snow will spread into Lassen
Volcanic National Park today, then into the Sierra by late
afternoon. Latest Weather Prediction Center guidance for this
system has trended a little higher, around 0.30 to 1.25" inches
of precipitation in the Valley, with the lower range around
Modesto, increasing to the higher range northward up the Valley.
Around 1.5" to around 2.25" is forecast over the mountains. Snow
levels initially start around 6500-7500 feet Sunday, then drop to
around 5000-6000 feet Monday. Total snowfall accumulations of 2 to
7 inches are currently expected above 6000 feet, with up to 16
inches at and near Lassen Volcanic National Park. This will bring
slippery roads and reduced visibilities at times, with possible
mountain travel delays and chain controls. A Winter Weather
Advisory continues for elevations above 6000 feet for the northern
Sierra and Lassen Park. There is the potential for minor
accumulations down to around 5500 feet, possibly a dusting down to
5000 feet. Periods of breezy southerly winds are possible today
ahead of the system, peaking in the morning. These have trended a
little weaker, with gusts in the Valley around 20 to 30 mph,
strongest over the northern Sacramento Valley and nearby
foothills. Heaviest period of rain is expected Sunday night, with
lingering showers into Monday evening. Heaviest snow is expected
late Sunday night through Monday morning, then gradually
diminishing Monday evening.


...Tuesday & Beyond...
Dry weather returns by early morning Tuesday. With potentially
clear skies behind the departing system, cold morning lows are
forecast on Tuesday, with low to mid 30s across the northern
Sacramento Valley and teens to 20s in the mountains. This could
bring the potential for morning frost, especially over the
northern Sacramento Valley and the foothills.

After the brief lull during the day Tuesday, confidence is now
high in a colder, wetter system arriving Tuesday night bringing
widespread rain, gusty southerly winds, and heavy mountain snow.
Latest forecast runs have increased even more for rainfall totals
and snow totals across interior NorCal. Current NBM probabilities
of at least 24 inches of snow above 5000 feet are around 90-100%
from late Tuesday night-Thursday night, and a 50-90% chance of
seeing 3 feet of snow. Snow levels will be lower with this system,
with accumulating snow above 4000 feet and potentially even
lower. Heavy snow amounts like this extending into lower
elevations than the previous storm have the potential to bring
significant travel impacts over a broad extent of mountain roads
early Wednesday through early Friday. Valley/Foothill rain
probabilities of an 1" inch or greater are now around 80-100%,
35-75% for 2" or greater. Thunderstorms are also possible
(10-20%), which could bring locally heavy rain, small hail and
gusty outflow winds. Ponding of water on roads and elevated small
streams are possible as well.

Forecast winds across northern Interior California have increased
in intensity. Gusty southerly winds look to develop late Tuesday
night and continue through the day Thursday. Latest forecast runs
bringing around 55-95% probability of wind gusts reaching at
least 35 mph on Wednesday, and a 35-75% probability of 45 mph,
with even stronger gusts possible. These winds bring the potential
for downed trees and local power outages.

We will continue to monitor trends on this mid to late week system,
especially as recent trends are leaning towards a stronger storm.
Make sure to keep checking the forecast for updates as we move
through the weekend and into early next week.

&&

.AVIATION...

VFR conditions with local MVFR/IFR ceilings at TAF sites through
today. Southerly winds increase up to 10-20 kts with gusts 20-30
kts today, strongest over the northern Sacramento Valley.
Southwest wind gusts over the Sierra Crest 35 kts after 18Z this
morning along with mountain MVFR/IFR/LIFR conditions in RA/SN.


&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 4 PM this afternoon to 10 PM PST
Monday for Lassen Volcanic NP-Sierra (Cal-Tuo) Above 5000 ft-
Sierra (El Dorado-Amador) Above 5000 ft-Sierra (Sierra-Placer)
Above 5000 ft.

&&

$$