Dunnigan, California Weather Forecast Discussion

274
FXUS66 KSTO 192038
AFDSTO
Area Forecast Discussion
National Weather Service Sacramento CA
138 PM PDT Fri Sep 19 2025
For additional details on weather and expected impacts over the
next 7 days, please visit weather.gov/sto/briefing.
.SYNOPSIS...
Remnants of former tropical storm Mario continue to shift through
the area today, with a large area of clouds and moisture. Back
edge of the clouds are moving through the Sacramento metro this
afternoon and reach the rest of northern CA this evening. We will
continue to see isolated to scattered showers and storms this
afternoon and evening along the Sierra and northern forecast area.
Shower activity will continue to diminish in the central valley
this afternoon and early evening. As we progress into the weekend,
remaining instability and lift from the former tropical system
helps generate isolated showers and storms along the Sierra crest
and coastal range tomorrow afternoon and evening. Drying
conditions as we close out the weekend and push into the new work
week. Chances for showers and storms mid next week, with
confidence increasing on the coverage being more isolated to
scattered than widespread.
&&
.KEY MESSAGES...
* TONIGHT - MONDAY:
- Remnants of former Tropical Storm Mario continue to shift
   through the area, with isolated to scattered showers and storms
   through the evening hours mainly in the northern forecast area
   and along the Sierra.
- Isolated showers and storms Saturday afternoon and evening
   along the crest and coastal range as remnant forcing and
   energy from the post tropical system lingers.
- 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. Elevated fire
   concerns are possible when low RH values co-locate with the
   breezy winds. Confidence remains low in this occurring.
* TUESDAY - THURSDAY:
- Latest CAMS continue to trend downward in the coverage and
   intensity of showers and thunderstorms mid next week. This is
   due to a deepening mid level trough shifting further southward
   into southern CA instead of northern CA. This would result in
   lower QPF for the region. We will monitor the latest guidance
   for any deviation in the system and any potential for more
   widespread precipitation chances.
.AVIATION...
Remnants of former Tropical Storm Mario continue to shift through
the area, with a large cloud deck moving through northern CA. The
edge of the clouds are making its way through the Sacramento
Metro this afternoon and reaches north toward Redding later this
evening. Ceilings remain VFR underneath the clouds, with patchy
areas of near MVFR. Isolated showers and storms are possible this
afternoon and evening, with dry conditions overnight. Winds will
remain light throughout the TAF period. Clearing conditions post
6z for each site.
&&
.STO WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$

NWS STO Office Area Forecast Discussion