FXUS66 KSTO 020141
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
641 PM PDT Wed Apr 1 2026


.KEY MESSAGES...

 - Unsettled weather continues for the remainder of today into
   tonight with showers and isolated thunderstorms. Snow continues
   at higher elevations overnight. Drying conditions by Thursday
   afternoon.

 - Winter Weather Advisory in effect until 8 AM Thursday for the
   western slopes of the Sierra above 6000 feet.

 - North to east winds develop on Friday, with dry and warm
   weather continuing into the weekend.

 - Temperatures warming to 80s this weekend.

&&

.DISCUSSION...

...Tonight-Thursday...
A fairly strong upper trough will slide across the Pacific
Northwest tonight. Main synoptic energy from this system will be
north of California but some lift combined with moist westerly
flow on the south side of it over California will still create
some precipitation. Snow should continue off and on over the
Sierra with snow levels during the main precipitation should be
above or around 6000 feet. Snow levels do crash later tonight but
precipitation is decreasing during that time.

As far as convection tonight. High resolution models and ensembles
are much less strong with forecasted CAPE with values from all
models only getting up to around 250 J/KG well below our local
guidance of 500 J/Kg. That being said, still some instability
around with HRRR still hinting at a Shasta County Convergence zone
setting up in eastern part of the county this evening. Otherwise
the strong westerly flow will create a pretty strong downslope
effect over the valley with limited valley precipitation.

...Friday through Monday...
Ensembles in good agreement that the above trough is very
progressive and pushes into Northern Plains by Friday. As it does
riding starts to build back into the area. As it does, we will
have a period of northerly winds Thursday night into Friday. Seems
like it should remain below wind advisory criteria and strongest
will be on the western and north portions of the Sacramento
Valley. Temperatures rise through this period and peak on Sunday
in the lower to mid 80s. HeatRisk remains on the low side.

...Tuesday...
Both EC and GFS showing a compact little upper low approach the
area and drive into the ridge in place early next week. Confidence
pretty low with this with the strength of the ridge. Probabilities
of precipitation from the NBM look good given this scenario with
at this time this system looks low impact but that could change as
we keep an eye on it. WMR

&&

.AVIATION...

General MVFR to VFR conditions over the next 24 hours across the
area from -SHRA, TSRA, and additional cloud cover. Periods of IFR
to MVFR conditions possible over the northern Sac. Valley to
the Cascades from 20z Wed to 05z Wed from scattered thunderstorms
over the area. South to southwest gusts 15 to 25 kts, up to 30
kts over the northeastern foothills and northern Sac. Valley until
around 05z where gusts lessen to 10 to 20 kts, up to 25kts, then
light and variable after 12z Thursday in the Valley.

Along the Sierra, gusts of 35 to 45 kts expected into 12z Thursday
before weakening. Additionally periodic IFR to MVFR conditions
from scattered snow showers above 6000 feet, tapering off after
12z Thursday.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 8 AM PDT Thursday for West Slope
Northern Sierra Nevada.

&&

$$