667
FXUS66 KSTO 241847
AFDSTO
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SACRAMENTO CA
1147 AM PDT SUN MAY 24 2026
FOR ADDITIONAL DETAILS ON WEATHER AND EXPECTED IMPACTS OVER THE
NEXT 7 DAYS, PLEASE VISIT WEATHER.GOV/STO/BRIEFING.
KEY MESSAGES
- GUSTY SOUTHWESTERLY WINDS THROUGH MONDAY COMBINED WITH LOW
DAYTIME RHS, WILL LEAD TO ELEVATED FIRE WEATHER CONDITIONS IN
THE VALLEY.
- ELEVATED FIRE WEATHER CONDITIONS IN THE VALLEY TUESDAY-
WEDNESDAY DUE TO GUSTY NORTH WINDS AND LOW HUMIDITY.
- CHANCES FOR ISOLATED SHOWERS/THUNDERSTORMS TUESDAY-THURSDAY
AFTERNOON AND EVENING OVER THE SIERRA AND SHASTA COUNTY.
DISCUSSION
..TODAY THROUGH MONDAY
WE CONTINUE TO SEE CLEAR SKIES ACROSS THE AREA, WITH A FEW CUMULUS
CLOUDS IN THE SIERRA (SOUTH OF HIGHWAY 50) AND NEAR THE COASTAL
RANGE. TEMPERATURES ARE EXPECTED TO CLIMB INTO 80S TO LOWER 90S
THIS AFTERNOON, WITH MINIMUM RH VALUES IN THE TEENS TO 20S FOR
PORTIONS OF THE VALLEY. WINDS REMAIN OUT OF THE SOUTH TO SOUTHWEST
TODAY, WITH A FEW GUSTS TO 25MPH POSSIBLE. PERIODIC ELEVATED FIRE
WEATHER CONDITIONS THIS AFTERNOON AND EVENING DUE TO THE LOW RH
VALUES COMBINED WITH THE BREEZY SOUTH TO SOUTHWESTERLY WINDS.
CONTINUED ELEVATED FIRE WEATHER CONDITIONS ON MEMORIAL DAY AS WE
WILL SEE LOW RH VALUES, WITH INCREASED SOUTH TO SOUTHWESTERLY
WINDS. HIGHEST WINDS WILL BE ON MONDAY, WITH OCCASIONAL GUSTS OF
30-40MPH FOR THE SIERRA, SHASTA COUNTY, AND AREAS IN THE NORTHERN
SACRAMENTO VALLEY.
THERE WILL BE A ISOLATED THREAT FOR SHOWERS AND THUNDERSTORMS
THIS AFTERNOON AND EVENING FOR AREAS SOUTH OF HIGHWAY 50 WITHIN
THE SIERRA. CHANCES ARE LOW DUE TO THE LIMITED MOISTURE AND
INSTABILITY ACROSS THE AREA. PLEASE BE MINDFUL OF ANY HOLIDAY
WEEKEND ACTIVITIES THAT INVOLVE FIRE/FLAME; THE FUELS WILL ONLY
CONTINUE TO DRY AS WE DIVE INTO THE DRY SEASON.
..TUESDAY THROUGH SATURDAY
A LOW PRESSURE SYSTEM MOVES AWAY FROM THE REGION WITH THE
BACK EDGE OF THE SYSTEM BRINGING NORTHERLY WINDS, LOW RH VALUES,
AND CHANCES FOR SHOWERS/THUNDERSTORMS. TUESDAY WE WILL START TO
SEE THE WINDS SHIFT TOWARD THE NORTH THROUGHOUT THE DAY.
TEMPERATURES WILL BE AT OR BELOW AVERAGE, WITH HIGHS IN THE 70S
ACROSS THE AREA. COOLER TEMPERATURES EXPECTED IN THE MOUNTAINS.
THE WINDS FULLY SHIFT TOWARD THE NORTH ON WEDNESDAY, WITH GUSTS
INCREASING THROUGHOUT THE DAY. AREAS ALONG AND WEST OF I-5 HAVE
THE BEST CHANCE TO SEE GUSTS 35-45MPH ON WEDNESDAY, WITH LOWER
WINDS AS YOU MOVE TOWARD THE NORTHERN SAN JOAQUIN VALLEY AND
SIERRA (SOUTH OF HIGHWAY 50). GUIDANCE OVER THE PAST 24-48 HOURS
HAS TRENDED THE WINDS LOWER ALONG WITH SLIGHTLY INCREASING RH
VALUES. THE PROBABILISTIC RANGE OF THE 25TH-75TH PERCENTILES HAS
GOTTEN SMALLER, WITH LITTLE VARIABILITY BETWEEN WIND, RH, AND
TEMPERATURE VALUES FOR AREAS IN THE VALLEY. THIS IS AN INDICATION
OF SOME CONSENSUS ON THE WINDS, TEMPERATURE, AND RH VALUES AS THE
NBM HAS GOTTEN A BETTER HOLD OF THE TRACK OF THE LOW PRESSURE
SYSTEM. NONE THE LESS, DUE TO THE LOW RH VALUES AND GUSTY
NORTHERLY WINDS, FIRE CONCERNS ARE STILL ELEVATED FOR THE VALLEY
LATE TUESDAY THROUGH WEDNESDAY. CONFIDENCE IS AROUND 40 PERCENT
FOR ANY FIRE WEATHER RELATED PRODUCTS DURING THIS TIME. WE WILL
CONTINUE TO MONITOR CONDITIONS FOR TUESDAY THROUGH WEDNESDAY FOR
THE NEED OF ANY WIND OR FIRE WEATHER PRODUCTS AS WE MOVE THROUGH
THE HOLIDAY WEEKEND.
TEMPERATURES REMAIN IN THE LOW TO MID 80S ACROSS THE AREA
WEDNESDAY THROUGH FRIDAY, WITH A SLIGHT INCREASE TOWARD THE MID TO
UPPER 80S BY THE WEEKEND. THE GRADUAL WARM UP IS DUE TO THE LOW
PRESSURE SYSTEM MOVING AWAY FROM THE REGION AND A RIDGE OF HIGH
PRESSURE BUILDING IN.
BESIDES THE HEAT, WINDS, AND FIRE CONDITIONS WE WILL SEE A CHANCE
FOR SHOWERS AND THUNDERSTORMS TUESDAY THROUGH THURSDAY FOR THE
MOUNTAINS AND AREAS AROUND SHASTA COUNTY. THE BEST CHANCES LIE IN
THE SIERRA BOTH WEDNESDAY AND THURSDAY WHERE INSTABILITY AND
MOISTURE AT THE HIGHER ELEVATIONS IS THE HIGHEST. A FEW STRONGER
STORMS CAN'T BE RULED OUT, WITH THE POTENTIAL FOR SMALL HAIL AND
GUSTY WINDS.
AVIATION
VFR CONDITIONS THROUGH THE TAF PERIOD, WITH SOUTH TO SOUTHWESTERLY
WINDS THIS EVENING FOR THE SACRAMENTO SITES. GUSTS TO 20KTS ARE
POSSIBLE AT TIMES THIS EVENING FOR MCC, MHR, SAC, AND SMF. SCK
AND MOD WILL SEE NORTH TO NORTHWESTERLY WINDS THIS EVENING.
CONDITIONS GO LIGHT AND VARIABLE OVERNIGHT, WITH CLEAR SKIES.
STO WATCHES/WARNINGS/ADVISORIES
NONE.
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