244
FXUS66 KSTO 112051
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
151 PM PDT TUE AUG 11 2026
FOR ADDITIONAL DETAILS ON WEATHER AND EXPECTED IMPACTS OVER THE
NEXT 7 DAYS, PLEASE VISIT WEATHER.GOV/STO/BRIEFING.
KEY MESSAGES
- SHOWER AND THUNDERSTORM CHANCES SOUTH OF I-50 TODAY, WITH
INCREASING CHANCES AND COVERAGE FOR A MIX WET AND DRY STORMS
WEDNESDAY AND THURSDAY.
- RED FLAG WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
THURSDAY EVENING FOR A MIX WET/DRY THUNDERSTORMS AND STRONG
OUTFLOW WINDS FOR ELEVATIONS ABOVE 3000 FEET IN THE SIERRA.
- SLIGHTLY COOLER, BUT STILL HOT, THROUGH WEDNESDAY, FOLLOWED BY
NOTABLY COOLER TEMPERATURES FOR THE REMAINDER OF THE WEEK.
- ISOLATED THUNDERSTORMS POSSIBLE ON WEDNESDAY SOUTH OF I-50 OVER
THE SIERRA CREST, WHILE DRY WEATHER AND BELOW-NORMAL
TEMPERATURES ELSEWHERE.
DISCUSSION
LATEST IR SATELLITE IMAGERY DEPICTS MID-LEVEL
MOISTURE SPREADING INTO THE REGION FROM THE SOUTHWEST THIS
AFTERNOON. THIS MOISTURE ALONG WITH DIURNAL HEATING WILL PROMOTE
SHOWER AND THUNDERSTORM CHANCE (10-15%) ALONG THE SIERRA CREST
THIS AFTERNOON AND EVENING. ELSEWHERE, DRY WEATHER AND SLIGHTLY
COOLER, BUT REMAINING HOT, TEMPERATURES ARE EXPECTED.
THE UPPER-LEVEL TROUGH SETTLES OVER THE REGION ON WEDNESDAY.
MONSOONAL MOISTURE WILL BRING AN INCREASING CHANCES (15-30%) OF
THUNDERSTORMS WEDNESDAY AND THURSDAY, ESPECIALLY ALONG THE SIERRA
FOOTHILL AND CREST. ISOLATED TO SCATTERED THUNDERSTORMS WILL BE
LIKELY SOUTH OF I-80 ON WEDNESDAY, THEN EXPANDED NORTHWARD TO THE
NORTHERN SIERRA AND INTO THE CASCADES ON THURSDAY. MODEL SOUNDINGS
SUGGEST A MIX OF WET AND DRY STORMS OVER THE MOUNTAINS. IN
COMBINATION WITH ERRATIC OUTFLOW WINDS UP TO 35 MPH AND DRY
FUELS, THESE WILL BRING A TREAT FOR NEW FIRE STARTS AND RAPID
SPREAD, EVEN IF WETTING RAIN FALLS WITHIN STORM CORES. THE NAM
AND GFS SUGGEST SOME NOCTURNAL ACTIVITY APPROACHING FORM THE
SOUTH LATE WEDNESDAY-THURSDAY. HAVE TO HOIST A FIRE WEATHER WATCH
FOR LATE WEDNESDAY THROUGH THURSDAY EVENING FOR THUNDERSTORMS WITH
LIGHTNING AND GUSTY WINDS FOR ELEVATIONS ABOVE 3,000 FEET IN THE
SIERRA.
SUCH PATTERN WILL BRING NOTABLY COOLER TEMPERATURES ACROSS
INTERIOR NORCAL THURSDAY AND FRIDAY, WITH HIGHS IN THE 80S ACROSS
THE VALLEYS, MID 90S TO MID 80S FOR THE FOOTHILLS AND 60S FOR THE
MOUNTAINS.
MONSOONAL MOISTURE WILL GRADUALLY PUSH BACK OUT OF THE AREA AFTER
FRIDAY. AS RESULT, THUNDERSTORMS CHANCES BEGIN TO DECREASE TO 10%
OR LESS ALONG THE SIERRA CREST HEADING INTO THE WEEKEND AS BELOW
NORMAL TEMPERATURES AND DRIER WEATHER SETTLE IN ELSEWHERE.
AVIATION
VFR CONDITIONS TO PREVAIL ACROSS INTERIOR NORCAL
NEXT 24 HOURS. ONSHORE FLOW INCREASES THIS AFTERNOON/EVENING WITH
WEST GUSTS AROUND 20 KTS IN THE SACRAMENTO AREA, SOUTH GUSTS UP TO
20 KTS IN THE NORTHERN SACRAMENTO VALLEY, AND WEST GUSTS 25 KTS
IN DELTA. WINDS DECREASE IN STRENGTH AROUND 11Z WEDNESDAY.
STO WATCHES/WARNINGS/ADVISORIES
FIRE WEATHER WATCH FROM LATE WEDNESDAY NIGHT THROUGH THURSDAY
EVENING FOR SIERRA (CAL-TUO) 3000-5000 FT-SIERRA (CAL-TUO) ABOVE
5000 FT-SIERRA (EL DORADO-AMADOR) ABOVE 5000 FT-SIERRA (SIERRA-
PLACER) ABOVE 5000 FT-SIERRA (TEHAMA-PLUMAS) ABOVE 3000 FT-
SIERRA (YUBA-PLACER) 3000-5000 FT-SIERRA 3000-5000 FT.
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