359
FXUS66 KSTO 261817
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
1117 AM PDT Wed Aug 26 2026
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.KEY MESSAGES...
- Dry with seasonable high temperatures through Thursday, with a
cool down by the weekend.
- Subtropical moisture moves into the area Friday morning,
bringing slight Valley rain shower chances and isolated
mountain rain shower/t-storm chances.
- Elevated Fire Weather conditions in portions of the Valley and
Foothills Today and Thursday.
&&
.DISCUSSION...
Mostly clear skies across interior NorCal this afternoon, with a
few mid to upper level clouds rolling through the Valley.
ALERT California cameras show some lingering haze in portions of
the northern Sacramento Valley again this morning as well. Overall
weather pattern to remain relatively unchanged compared to
previous few days, with upper level high pressure in/near the Four
Corners region and offshore troughing in the PacNW. We will keep
this pattern in place through tomorrow afternoon, then the PacNW
trough will begin to dig further into the region, ushering in
cooler temperatures, rain shower chances, and breezy winds Friday
morning through early Saturday morning. Those hoping to catch a
view of the partial lunar eclipse might be met some cloud coverage
as the approaching system moves closer to the area, so make sure
to check your local cloud coverage/sky forecast at weather.gov/sto
and entering your zip code to get specific information.
The PacNW trough will tap into a subtropical moisture plume early
Friday as an embedded shortwave pulse moves inland. Recent model
runs have revealed enough moisture and energy will be present to
pose a Valley rain shower chance beginning early Friday morning
and continuing through most of the afternoon. Ensembles have also
revealed a further northern extent of the moisture plume, so our
forecast has been adjusted to reflect at least a 15% chance of a
shower in most of the Sacramento Valley on Friday. As the energy
moves further inland, isolated thunderstorms will also be possible
along/near the Sierra crest in the afternoon and evening hours.
Confidence is relatively low on activity building west of the
crest, as forecast soundings reveal little instability aloft.
Winds will also increase across most of the area Friday, with the
potential for 30 mph gusts in the northern Sacramento Valley
mainly north of Chico and into Redding. Activity will gradually
move out of the area by the overnight hours into Saturday morning.
Latest rain totals have modest totals of around 0.50" inches south
of HWY-50 in the mountains, with around a trace to 0.10" in the
foothills and areas north of I-80 in the higher elevations.
High temperatures will begin to fall below seasonal norms on
Monday, with early fall-like highs expected Monday and Tuesday
across the area. Something we will continue to monitor for next
week is the potential for post-tropical cyclone/subtropical
moisture again making a push into the region by the middle of next
week. The EC is not as excited as the GFS in terms of bringing
additional rain shower chances to the region, but it will
continue to be monitored as we move through the rest of the week.
&&
.AVIATION...
VFR conditions prevail across interior NorCal next 24 hours.
Surface wind gusts generally below 12 kts. Surface wind gusts in
Delta vicinity up to 20 kts from 22z today through 03z Thursday.
Mountain surface wind gusts up to 25 kts.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
