Area Forecast Discussion
Issued by NWS Sacramento, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
000
FXUS66 KSTO 230906 AAA
AFDSTO

Area Forecast Discussion...UPDATED
National Weather Service Sacramento CA
206 AM PDT Sat Mar 23 2024

.Synopsis...
Periods of widespread rain, heavy mountain snow, breezy winds,
and cooler weather continues today with the current storm system.
Drier conditions early next week with additional storms possible
midweek.

&&

.Discussion...
Light to moderate rain showers are ongoing early this morning with
snow showers ongoing over the Sierra. As of midnight this morning,
the wettest locations were the Northern Sacramento Valley
(~1.50-2.50 inches) and the Feather River Valley (~1.50-1.75
inches). Peak gusty winds were also observed with 25 to 45 MPH
gusts throughout the Valley on Friday.

Conditions lighten this morning with more waves of precipitation
in store through Sunday morning. A Winter Storm Warning remains in
effect until 8 AM Sunday as periods of heavy snow continues
today for elevations above 4000 feet. 1 to 2 feet of additional
snow accumulations is forecasted in the Sierra with winds gusting
20-45 MPH at higher elevations. Snow levels are 3750 to 5000 feet
this morning, becoming 3000 to 4000 feet Sunday morning. Heaviest
period of snowfall will be this afternoon and evening. NBM
probabilities show a 50-90% chance of exceeding 12 inches as a
storm total in the Sierra for elevations above 4500 feet. For 18
inches, probabilities lower to 25-50% chance.

Additionally, snow will occur across the North Coast Range and
Shasta County Mountains above 4000 feet with 4 to 10 inches,
locally up to 18 inches at the highest peaks. Winds gust up to 35
MPH before tapering off this evening. NBM probabilities show a
30-55% chance of storm total snow exceeding 4 inches for
elevations above 4000 feet across Shasta County and the Coastal
Range. A Winter Weather Advisory is in effect through 8 AM for
portions of the northern Coast Range and Shasta County Mountains
above 4000 feet.

Widespread rain repeats again today with today`s total amounts
0.10-0.50" in the Valley, 0.50-1.00" and up to 1.25" across the
foothills and Northern Sacramento Valley. People should
plan for slick roads this weekend. Locally heavier rain amounts
can be expected with any thunderstorms that develop. The NBM
projects a 25 to 45 percent probability of thunderstorm
development today with the best chances in the afternoon and
evening hours. With any thunderstorms that develop, brief heavy
rain, small hail, gusty winds, lightning and even brief funnel
clouds will be possible.

Today should see lighter south winds today with only 15 to 30 MPH
Valley wind gusts forecasted, up to 40 MPH in the northeast
foothills. Please continue to secure loose objects outside and
watch for downed tree branches and limbs.

Rainfall should begin to taper off tonight with lingering showers
in the foothills and snow showers across the Sierra through Sunday
morning. Drier conditions develop tomorrow afternoon as ridging
moves over northern CA and our weather system moves into the
Great Basin area. There will be some weak showers across the
Sierra and Northern Sacramento Valley on Monday but little to no
impacts are expected with minor precipitation accumulations
forecasted. Please continue to check the latest forecast and road
conditions as you continue to travel this weekend, especially
those with mountain travel plans.

&&

.EXTENDED DISCUSSION (Wednesday THROUGH Saturday)...

Pacific frontal system progged through interior NorCal Wednesday
bringing widespread rain, mountain snow, and gusty wind. Post
frontal showers possible with associated upper trough Thursday.
Unsettled weather continues Friday into Saturday as models show
another short wave trough moving inland as it develops into upper
low. Model differences with track of this wave leading to some
forecast uncertainty with amount of associated precip at this
time. WPC storm total QPF 12z Wed through 12z Sat showing around 8
tenths of an inch in the N San Joaquin Valley to over 1 and
three-quarters of an inch in portions of the N Sac Valley. In the
foothills/mountains liquid storm totals run from around 1.5 inches
to locally up to 5 inches in the wettest mountain spots. Snow
levels begin around 5000-6000 Wednesday, lowering to 3500-4500
feet Thursday into the weekend. Several feet of additional new
snow possible over the higher elevations through the extended
forecast period.

&&

.AVIATION...

In Central Vly, scattered MVFR/IFR conditions possible next 24 hrs
in shwrs and isolated/widely scattered tstms. In Sac Vly, widespread
Sly sfc wind 15-25 kts with lcl gusts up to 35 kts til 04z Sun.
In foothills/mtns, widespread MVFR/IFR with lcl LIFR obscurring
trrn next 24 hrs in shra/shsn. Snow levels 4000-4500 ft AMSL
today, lowering to 3000-4000 ft AMSL tonight. Isolated tstms
possible. Areas S-W sfc wind gusts 30-40 kts possible over hyr
trrn.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 5 AM PDT Sunday for Mountains
Southwestern Shasta County to Western Colusa County-Shasta Lake
Area / Northern Shasta County.

Winter Storm Warning until 5 AM PDT Sunday for West Slope
Northern Sierra Nevada-Western Plumas County/Lassen Park.

&&

$$


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.