553
FXUS66 KSTO 151905
AFDSTO

Area Forecast Discussion
National Weather Service Sacramento CA
1205 PM PDT Tue Sep 15 2026

.KEY MESSAGES...

  - Cooler weather, increased humidity, and precipitation chances
    are in store Wednesday-Thursday, best chances across Coast
    Range, Shasta County, and Southern Cascades area.

  - Late week into the weekend will see conditions warm to near
    normal temperatures with drying conditions, particularly over
    the northern Sacramento Valley

&&

.DISCUSSION...

Today:
Fairly benign weather today with similar afternoon highs with a
slight increase in moisture compared to yesterday, as our north
winds died off yesterday evening. There is a slight chance of
showers over portions of northern Shasta this late evening into
Wednesday AM but best chances remain in Siskiyou and Modoc county
areas. Breezy afternoon winds expected with gusts up to 20 MPH.

Wednesday-Thursday:
First day of cooler weather with highs in the low to mid 80s in
the Valley and upticks in humidity through Thursday. A Pacific NW
low is still expected to track south into our area bringing
chances for showers & isolated thunderstorms around the mountains
of Shasta County and Southern Cascades. Today`s run of models
generally kept activity along the Coast Range crest westward and
over the northern Shasta County Border on Wednesday with around a
15-25% of precipitation occurring. Minimal precipitation is
expected but with this comes thunderstorm chances (10-20%) which
could bring brief heavy rain showers, lightning, gusty winds, and
possible fire starts so please be sure to check the latest
conditions before you go.

Thursday will see the closed low weaken and begin to drift
eastward as high pressure builds over the Pacific NW. This will
still keep precipitation chances in the area but a reduced
thunder threat and lower impact chances all around for our area.
Best chances for precipitation will be in morning - early
afternoon with the system wrapping up by the late evening.
Precipitable water forecasts continue limited support for any
widespread thunderstorm development at the moment but Thursday has
trended wetter but CAMs keep the bulk of storms outside of our
area.

Friday-Weekend
Beyond Thursday, high pressure begins to develop again and will
see temperatures rebound to near seasonable and dry conditions,
particularly over the northern Sac. Valley, and breezy afternoon
winds.

As always, be sure to follow the forecast at
weather.gov/sacramento for any updates!

&&

.AVIATION...

General VFR conditions prevail across TAF sites over the next 24
hours, except period of local MVFR ceilings from 11Z-17Z vicinity
Sacramento area terminals (30-50% chance). Southerly winds with
gusts 15-25 kts at times today through Wednesday with southwest
gusts 20-30 kts in the Delta and over the Sierra Crest and west-
northwest gusts 15-30 kts in the Diablo Range and northern San
Joaquin Valley.

&&

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

$$