Galt, California Weather Forecast Discussion

283
FXUS66 KSTO 201944
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
1244 PM PDT Sat Sep 20 2025
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.SYNOPSIS...
Isolated to scattered shower/thunderstorm potential continue in
the mountains and northern Sacramento Valley today and tomorrow.
Warming and drying trend occurs Monday and Tuesday with breezy
northerly winds. Unsettled weather potentially returns mid-next
week.
&&
.KEY MESSAGES...
* TODAY - TUESDAY:
- Isolated showers and thunderstorms this afternoon and evening
   along the Sierra crest, southern Cascades, Shasta County
   mountains, and Coast Range (10-30%), with limited chances in
   the northern Sacramento Valley (10-15%), as remnant forcing and
   energy from the post tropical storm Mario lingers. Highest
   chances in the Shasta County mountains.
- No debris flow impacts are expected as there is a less than 10
   percent chance for thresholds to be reached in areas where
   thunderstorms develop near burn scars.
- Ridge builds in Sunday and Monday, with drying conditions and
   breezy northerly winds Sunday night into Monday. Breezy
   downslope winds expected along the Sierra Crest on Tuesday,
   with lingering breezy north winds in the Valley. Briefly
   elevated fire concerns are possible when low RH values co-
   locate with the breezy winds. Confidence remains low in this
   occurring.
* WEDNESDAY - FRIDAY:
- NBM probabilities for thunderstorms have trended down for
   Wednesday along most of the Sierra Crest, except south of I-80,
   where chances remain around 10-25%.
- Lingering chances for isolated thunderstorms remain on Thursday
   and Friday along the crest, around 10-20% and highest south of
   I-80.
- There is still uncertainty in the path of the trough that would
   bring these isolated storms, so overall confidence is still low
   in spatial coverage and timing of storms. We will continue to
   monitor the latest guidance for any deviation in the system and
   potential for more widespread precipitation.
.AVIATION...
VFR conditions are forecast over the next 24 hours across TAF
sites with light winds less than 12 kts. Isolated showers and
thunderstorms will bring localized MVFR/IFR conditions from
19Z-03Z today over the southern Cascades, Coast Range and Shasta
County mountains, and then again after 19Z Sunday but in the
Sierra south of US 50. North to east winds begin to increase after
06Z Monday.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS STO Office Area Forecast Discussion