045
FXUS66 KMTR 130053
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
553 PM PDT FRI SEP 12 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 112 PM PDT FRI SEP 12 2025
- DRIER AND SLIGHTLY WARMER WEATHER TODAY AND SATURDAY.
- MUCH WARMER CONDITIONS EARLY NEXT WEEK WITH INLAND MODERATE
HEATRISK POSSIBLE.
SHORT TERM
ISSUED AT 112 PM PDT FRI SEP 12 2025
(THIS EVENING THROUGH SATURDAY)
STRATUS LINGERS ACROSS THE COASTAL REGIONS, WITH THE INLAND AREAS
MOSTLY CLEAR SAVE SOME FAIR WEATHER CUMULUS ON THE RIDGELINES OF THE
INTERIOR MOUNTAINS. THE UPPER LEVEL LOW THAT BROUGHT US THE COOLER
TEMPERATURES AND SHOWERS HAS STARTED TO MOVE OFF TO THE EAST, BEHIND
WHICH A NARROW BUT STOUT RIDGE IS BUILDING INTO THE WEST COAST. THIS
IS RESULTING IN A WARMING AND DRYING TREND THROUGH THE WEEKEND, WITH
HIGH TEMPERATURES TODAY RANGING FROM THE UPPER 70S TO THE MIDDLE
80S, UP TO THE UPPER 80S TO THE LOWER 90S IN THE WARMEST SPOTS, THE
LOWER TO MIDDLE 70S NEAR THE BAYS, AND THE MIDDLE TO UPPER 60S AT
THE PACIFIC COAST. STRATUS WILL EXPAND INLAND OVERNIGHT, BEFORE
RETREATING TO THE COAST AGAIN ON SATURDAY MORNING. HIGHS ON
SATURDAY WILL BE SIMILAR TO TODAY'S.
LONG TERM
ISSUED AT 112 PM PDT FRI SEP 12 2025
(SATURDAY NIGHT THROUGH NEXT THURSDAY)
THE RIDGE ERODES ON SUNDAY WITH THE PASSING OF AN UPPER LEVEL TROUGH
ACROSS THE PACIFIC NORTHWEST, BUT ANY COOLING EFFECTS WILL BE
LIMITED TO A COUPLE DEGREES ACROSS THE FAR NORTHERN REACHES OF
SONOMA AND NAPA COUNTY, AND THERE IS NO RAINFALL IN THE FORECAST.
RIDGING RETURNS TO THE WESTERN US ON MONDAY, WITH HIGHS REACHING THE
UPPER 80S TO THE MIDDLE 90S INLAND. CLOSE TO THE BAYS AND THE COAST,
THE TEMPERATURES REMAIN RATHER UNCERTAIN, DEPENDENT ON THE STRENGTH
OF ANY OFFSHORE FLOW THAT DEVELOPS IN THE REGION. THE CURRENT
FORECAST FOR TUESDAY, CURRENTLY EXPECTED TO BE THE WARMEST DAY OF
THE NEXT WEEK, HAS HIGH TEMPERATURES REACHING THE MIDDLE 70S TO THE
MIDDLE 80S NEAR THE BAYS, AND THE UPPER 60S TO LOWER 70S ALONG THE
PACIFIC COAST. STRONG OFFSHORE FLOW CAN EASILY ADD 5 DEGREES OR MORE
TO THOSE READINGS. MODERATE HEATRISK IS POSSIBLE ACROSS THE INLAND
VALLEYS INTO THE MIDDLE OF NEXT WEEK, MEANING THAT A MODERATE RISK
FOR HEAT-RELATED ILLNESSES EXISTS FOR VULNERABLE POPULATIONS,
INCLUDING CHILDREN, THE ELDERLY, PREGNANT WOMEN, PEOPLE WITH CERTAIN
CHRONIC ILLNESSES, AND PEOPLE WORKING OR LIVING OUTDOORS WITHOUT
ADEQUATE SHELTER OR HYDRATION.
FROM THE PREVIOUS FORECASTER: NEXT THURSDAY AND BEYOND GET PRETTY
INTERESTING ON THE LONG RANGE FORECAST. KIND OF FANTASY LAND AT THIS
POINT, BUT THERE ARE SIGNS WE'LL NEED TO WATCH FOR ANOTHER ROUND OF
TROPICAL/MONSOONAL MOISTURE SURGE. IT'S TOO EARLY FOR DETAILS, BUT
LONGER RANGE GLOBAL ENSEMBLES/CLUSTER SHOW TRANSPORT FLOW THAT WOULD
BRING DECAYING TROPICAL SYSTEM MOISTURE WITH A HINT OF MONSOONAL.
GFS MODEL FOR INSTANCE HANDLED THE EARLY SEPTEMBER LIGHTNING EVENT
BETTER THAN OTHERS. IT'S FANTASY LAND PICTURE FOR THE 19-20TH OF
SEPT SHOWS SHOWERS AND THUNDERSTORMS OVER CENTRAL CALIFORNIA. AT
THIS POINT, IT WORTH KEEPING AND EYE ON. TIMING WOULD BE BAD FROM A
FIRE WEATHER STAND POINT AS WARMER WEATHER DEVELOPS OVER THE WEEKEND
AND PEAKS EARLY NEXT WEEK.
AVIATION
(00Z TAFS)
ISSUED AT 552 PM PDT FRI SEP 12 2025
EXPECT MODERATE TO BREEZY WINDS TO CONTINUE INTO THE EVENING BEFORE
REDUCING INTO THE NIGHT. PATCHES OF LOW CLOUDS ARE AFFECTING HAF AND
AND THE MONTEREY BAY TERMINALS. STATUS INCREASES AND MOVES INLAND
INTO THE NIGHT BECOMING WIDESPREAD INTO SATURDAY MORNING. POCKETS OF
FOG LOOK TO AFFECT STS IN THE EARLY TO MID MORNING. CLOUD COVER WILL
BE SLOW TO ERODE ON SATURDAY, BUT NEARLY WIDESPREAD VFR IS EXPECTED
INT THE AFTERNOON. THE EXCEPTION, BEING HAF, WHICH SEES CIGS RISE TO
MVFR LEVELS, BUT DON'T CLEAR. SATURDAY AFTERNOON OFFERS ANOTHER
ROUND OF MODERATE TO BREEZY WINDS ARRIVE AND LAST INTO THAT EVENING.
CLOUD COVER BUILDS AROUND THE MONTEREY BAY IN THE LATE AFTERNOON AND
AROUND THE SF BAY THAT EVENING.
VICINITY OF SFO...BREEZY WINDS LINGER INTO THE EVENING. MVRF CIGS
FILL OVER SFO INTO THE EARLY NIGHT NIGHT AND STAY IN PLACE THROUGH
THE NIGHT AND SATURDAY MORNING. THESE CIGS ERODE AS BREEZY WEST WINDS
BUILD SATURDAY AFTERNOON, BUT CIGS RETURN AS THE WINDS REDUCE INTO
THAT NIGHT.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...MVFR/IFR CIGS ARE BUILDING AROUND THE THE
BAY WITH WINDS EXPECTED TO REDUCE IN THE MID EVENING. CIGS AT MRY
AND SNS LOOK TO FALL TO IFR LEVELS IN THE EVENING WITH WINDS
BECOMING LIGHT AND VARIABLE INTO THE LATE NIGHT. CIGS LIFT TO MVFR
LEVELS IN THE MID MORNING THEN ERODE INTO SATURDAY AFTERNOON AS
MODERATE WEST WIND BUILD.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 552 PM PDT FRI SEP 12 2025
A GENTLE TO MODERATE NORTHWESTERLY BREEZE WILL PERSIST ACROSS THE
REGION THROUGH MUCH OF THE FORECAST PERIOD. FRESH TO STRONG GUSTS
WILL BE POSSIBLE IN THE FAVORED COASTAL JET REGIONS AND ACROSS THE
OFFSHORE ZONES THROUGH THIS WEEKEND CREATING HAZARDOUS CONDITIONS
FOR SMALL CRAFT. MODERATE SEAS PERSIST, ESPECIALLY OFFSHORE.
ANOTHER ROUND OF WIDESPREAD FRESH TO STRONG NORTHWESTERLY BREEZES
BEGINS SUNDAY INTO NEXT WEEK WITH THE STRONGEST WINDS LOCATED
ACROSS THE FAR NORTHERN OUTER WATERS.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT SATURDAY FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM-PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM SATURDAY TO 3 AM PDT SUNDAY FOR
PT ARENA TO PT REYES 0-10 NM-PT PINOS TO PT PIEDRAS BLANCAS
0-10 NM.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...MURDOCK
MARINE...RGASS
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