717
FXUS66 KSTO 052048
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
148 PM PDT Sat Sep 5 2026

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



.KEY MESSAGES...

  - Mainly dry this weekend, with some mountain showers and
    thunderstorm chance (15-20%) Sunday over northern Shasta
    County.

  - Gradual warming trend this weekend and into early next week,
    but highs likely remain below average for this time of the
    year

  - There is a potential for showers and isolated thunderstorms
    mid to late next week, especially for the Sierra.

&&

.DISCUSSION... A broad-upper level trough centered over the
Pacific Northwest will persist through this weekend, before
weakens and shift northeastward early next week. A weak shortwave
is bringing mid- high-level clouds across the area from the
southwest today. However, dry weather conditions is expected, with
isolated showers possible over the Sierra crest this afternoon.
Daytime temperatures are running 5-10 degrees warmer this
afternoon compared with yesterday`s reading, with highs in the 70s
and 80s. Slightly warmer temperatures are forecast for Sunday,
but likely remain bellow normal for this time of the year. Another
embedded shortwave trough will swing through the region on Sunday
bringing isolated mountain showers and a slight chance (15-20%)
of thunderstorms to northern Shasta County. Generally dry is
expected elsewhere.

In addition, an enhanced in the onshore winds is expected. West
gusts up to 25 mph in the Delta possible, with up to 35 mph over
the Sierra.

Dry weather with warmer daytime temperatures is forecast for
Monday, Labor Day, as a surface high pressure begin to builds in
across the area. Breezy north winds with gusts up to 25 mph is
expected along the I-5 corridor on Monday.

There is a low confidence in the forecast for mid to late next
week as the models continue to have a disagreement regarding the
position of the cutoff off California and the remnants of Marie.
The GFS and ECMWF ensembles suggest PWAT anomaly generally about
150-200% above-normal across the area. Currently there is a
potential for showers and isolated thunderstorms over the Sierra
for mid-week. Meanwhile, temperatures trend warmer, with near to
above normal by mid to late next week.

&&

.AVIATION... Prevailing VFR conditions for the next 24 hours.
Valley winds light/VRB, becoming south to west around 5-10 kts
after 22Z. Winds over the Sierra W-SW at 5-15kt, with occasional
gusts at 15-25 kts. An enhanced in westerly winds is expected on
Sunday.

&&

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

$$