472
FXUS66 KSTO 311954
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
1254 PM PDT Tue Mar 31 2026
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.KEY MESSAGES...
- Potential for strong to severe thunderstorms in the northern
Sacramento Valley and Sierra mountains/foothills this
afternoon and evening. Primary hazards: 1 inch hail, weak
tornadoes.
- Winter Weather Advisory in effect from 5 AM Wednesday to 8 AM
Thursday for the western slopes of the Sierra above 6000 feet.
- A quick-moving system brings precipitation, thunderstorm
chances, and breezy to gusty south winds to the area today
through Thursday AM.
- North to east winds develop on Friday, with dry and warm
weather continuing into the weekend accompanied by Minor
HeatRisk.
&&
.DISCUSSION...
...Today-Thursday...
A fairly progressive system brings scattered light to moderate
rain, mountain snow, breezy to gusty southerly winds, and isolated
thunderstorms (cells may be strong to severe) to the region today
through Thursday AM.
Snow amounts have trended up with the latest forecast and as a
result, a Winter Weather Advisory is in effect from 5 AM
Wednesday to 8 AM PDT Thursday for the western slopes of the
Sierra above 6000 feet. Snow levels will be between 6500-7000 for
most of the day on Wednesday, before lowering to 6000-6500 feet
that evening. A few snow showers will linger over the Sierra
Thursday morning, but the majority of precipitation will have
exited the region. Currently 5 to 12 inches are forecast above
6000 feet, but higher accumulations are expected along the peaks.
The threat for isolated thunderstorms exists through the
Sacramento Valley and Sierra foothills today with probabilities
around 15-25%. A few strong to severe isolated thunderstorms may
develop across the northern Sacramento Valley and Sierra foothills
this afternoon and evening as well. The primary threats being severe
hail (1.00"+) as the primary hazard given sufficient CAPE and
0-6km shear along with chances for brief, weak tornadoes.
Thunderstorm chances continue on Wednesday as well, mainly over
Shasta County.
Periodic light to moderate beneficial rainfall will continue
today through Thursday morning, with the majority of
accumulations expected over Shasta County, mountains, and Sierra
foothills.
Additionally, breezy southerly winds will accompany this system
as well, with gusts of 25-35 mph in the Valley; strongest in the
northern Sacramento Valley and NE Foothills. Stronger south-
southwesterly wind gusts of 35-45 mph in the mountains will also
be possible on Wednesday.
...Friday-Monday...
By Friday, we will begin to dry out as the weather system moves
into the Northern Plains and ridging builds over the eastern
Pacific and Pacific northwest. This will allow for drying and
north to east winds to develop across the area. Current NBM
probabilities of 35 mph or more on Friday are around 60-90% along
and west of the I-5 corridor. High temperatures are forecast to
rise back into low to mid 80s in the Valley by Saturday and
through early next week, prompting the return of Widespread Minor
HeatRisk in the Valley on Sunday.
&&
.AVIATION...
General MVFR to VFR conditions over the next 24 hours across the
area from -SHRA and additional cloud cover. Periods of IFR to MVFR
conditions possible over the northern Sac. Valley from 18z Tues
to 03z Wed from scattered thunderstorms over the area. South to
southwest gusts 10 to 20 kts, up to 30 kts over the northeastern
foothills into 12z Wed before increasing to 15 to 30 kts north of
Interstate 80 through 18z Wed. Gusty winds 20 to 40 kts over the
Sierra into 12z Wed before increasing to 35 to 45 kts through 18z
Wed.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 5 AM Wednesday to 8 AM PDT Thursday
for West Slope Northern Sierra Nevada.
&&
$$
