166
FXUS66 KSTO 301907
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1207 PM PDT Thu Apr 30 2026

For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.

.KEY MESSAGES...

 - Mostly dry weather and warming temperatures through the end of
   the week with isolated mountain shower/thunderstorms

 - Next system this weekend into early next week with showers,
   high elevation mountain snow showers, thunderstorms, cooler
   temperatures and breezy winds

&&

.DISCUSSION...

...Today through Friday...
Latest satellite imagery from GOES-West shows sunny skies across
much of interior northern California with just a few high clouds
passing over the northern areas and some cumulus over the
mountains. Temperatures are currently trending around 3 to 6
degrees warmer than this time 24 hours ago. Upper level ridging
over the Pacific Northwest is bringing continued warming and
drying conditions to the region, along with light winds. Forecast
highs will warm to the 70s to 80s for the Valley and foothills,
and upper 50s to 70s in the mountains. Relative humidity will
trend slightly lower today and Friday. A few stray showers or an
isolated thunderstorm will be possible in the mountains south of
US Highway 50 this afternoon, and again over the Sierra and Coast
Range on Friday afternoon (up to 10 to 15 percent).

...Saturday through Wednesday...
Confidence continues to increase in a pattern change to unsettled
weather over the weekend into early next week. Renewed
precipitation chances are favored over this timeframe, in showers,
high elevation mountain snow showers and thunderstorms. The
latest forecast has the storm total precipitation trending
slightly higher, with snow amounts trending slightly lower. Only
minor snow accumulations are forecast at the highest peaks (up to
1 to 2 inches) with snow levels above the passes. The National
Blend of Models (NBM) currently advertises a 10 to 20 percent
chance of thunderstorms on Saturday and Monday, with a 20 to 40
percent chance on Sunday with best chances over higher terrain.
Model soundings are indicating Sunday afternoon and evening as the
best potential for strong to severe thunderstorms. We will
continue to evaluate the conditions as we get closer. Individuals
should check back frequently for forecast updates at weather.gov.
Cooler temperatures and periodically breezy onshore winds can also
be anticipated with this storm system. Precipitation tapers off
on Tuesday with a few lingering showers over the mountains, with
drier weather returning by Wednesday.

&&

.AVIATION...
VFR conditions at TAF sites next 24 hours. Light surface winds
generally 10 kts or less except in the Delta with west-southwest
winds 10 to 15 kts. Isolated light showers may develop over the
Sierra south of Highway 50 from 18Z-03Z Thursday, and again on
Friday after 18Z in the Sierra and Coast Range.

&&

.STO WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$