744
FXUS66 KSTO 221938
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
1238 PM PDT Thu Oct 22 2026
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.KEY MESSAGES...
- Scattered showers, thunderstorm chances, and high elevation
snow showers through this evening. Lingering mountain showers
Friday morning.
- Breezy north to east winds develop Friday afternoon into
Saturday AM, followed by weaker downsloping winds Sat PM-Sun
AM.
- Dry weather continues through most of next week, with potential
for unsettled weather Halloween Weekend.
.DISCUSSION...
...Today through Friday AM...
Cloudy skies and scattered showers are actively being observed
across interior Northern California. Some isolated moderate to
heavy rain will be possible at times, but precipitation will
largely be light to moderate. Shower activity will gradually
trend down through the afternoon hours, but a few scattered light
showers may linger over the Sierra. Given the cloud cover and lack
of instability as this weather system treks through Southern
California, the threat for thunderstorms has largely trended down,
but an isolated thunderstorm (10-15% chance) is still possible
over the Sierra and Motherlode this afternoon/early evening.
Forecast precipitation amounts for the remainder of the day are
around 0.10 to 0.20 inches in the Valley, with higher amounts just
over 0.50 inches along the Sierra.
Snow levels continue to be around 8000-9000 feet in the Sierra
today, with additional snowfall amounts of 1-3 inches at the
highest peaks. Best chance for snow will be toward Mono county
and into the Yosemite area. Minor impacts are possible at the
highest elevations in Tuolumne county and toward Alpine due to the
snow.
Low clouds and potential for fog development in the Valley
are possible tomorrow morning as well and may make the morning
commute difficult at times.
...Friday (rest of the day) through Monday...
Dry conditions are expected by Friday afternoon/evening, with RH
values dropping to the 20 to upper teens for portions of the
northern Sacramento Valley. As the trough digs into the
southwestern United States and ridging develops off the NorCal
coast, winds will shift out of the north in the Valley and north
to east along the slopes of the Sierra. We will see gusty winds
during the afternoon/evening on Friday with gust up to 35 mph
within the northern Sacramento Valley for areas along and west of
I-5. Areas within the mountains may see gusts up to 40 mph
especially through gaps and canyons. A weaker period of
downsloping winds is expected Saturday evening into Sunday
morning, with gusts 20 to 30 mph. No broad/large scale fire
weather concerns are anticipated given recent rainfall, but
isolated fire weather concerns will be possible in places in the
Sierra and Valley where little rainfall occurred.
Temperatures begin to trend higher as we head into next week as
ridging builds, but will remain a few degrees below normal. A few
isolated showers are possible over Shasta County Sunday and
Monday, but any amounts will be very light as a trough passes
through the Pacific Northwest.
...Tuesday and Beyond...
Dry weather continues through the rest of the work week, but there
is the potential for unsettled weather as we close out October
and head into November. Details are fairly uncertain since we`re
so far out, but this week will be an ideal time to clear gutters
and secure loose outdoor decorations and items in preparation for
any additional precipitation that comes our way.
&&
.AVIATION...
Showers and isolated thunderstorms continue through the afternoon
and evening hours, with localized areas of MVFR to IFR ceilings.
Best timeframe for thunderstorms will be 2000z through 0400z for
all sites with a 10-15% chance of occurrence. Winds will remain
light throughout the day outside of erratic winds near
thunderstorms. After 06z Friday, showers linger over the Sierra
into Friday 18z and fog and stratus in the Valley overnight after
09z Friday with lowered ceilings as low as IFR to LIFR ceilings.
Snow levels 7500-8500 feet until lowering after 12z Friday to
around 6000-8000 feet.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
