740
FXUS66 KMTR 120509
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1009 PM PDT THU SEP 11 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1204 PM PDT THU SEP 11 2025
- SLIGHT (15-25%) CHANCE FOR SHOWERS IN THE NORTH BAY THURSDAY
AFTERNOON
- DRIER AND SLIGHTLY WARMER WEATHER FRIDAY AND SATURDAY, MUCH
WARMER EARLY NEXT WEEK.
UPDATE
ISSUED AT 905 PM PDT THU SEP 11 2025
SATELLITE SHOWS STRATUS FILLING OVER OUR COASTAL WATERS, FORMING
OVER PORTIONS OF THE COASTS, AND TRYING TO BLOSSOM IN SOME OF THE
INTERIOR VALLEYS. THE EXPANSION OF STRATUS SHOULD CONTINUE,
LEADING TO ANOTHER CLOUD NIGHT. NO CHANGES TO THE FORECAST THIS
EVENING.
SHORT TERM
ISSUED AT 1204 PM PDT THU SEP 11 2025
(THIS EVENING THROUGH FRIDAY)
SATELLITE IMAGERY THIS AFTERNOON DEPICTS LINGERING STRATUS IN THE
CENTRAL PART OF THE BAY AREA AND THE HIGHER ELEVATIONS OF THE SANTA
CRUZ MOUNTAINS AND THE NORTHERN SANTA LUCIA RANGE. MEANWHILE,
CUMULUS CLOUDS ARE STARTING TO POP UP ACROSS THE INTERIOR MOUNTAINS
FROM THE MAYACAMAS OF SONOMA AND NAPA COUNTIES THROUGH THE MOUNTAINS
AT THE EASTERN EDGE OF SANTA CLARA COUNTY, DOWN TO THE AREA NEAR AND
SOUTH OF SAN BENITO MOUNTAIN AND ALONG THE EASTERN EDGE OF MONTEREY
COUNTY. THE LATEST FORECAST UPDATE KEEPS A SLIGHT CHANCE FOR SHOWERS
(15-25% PROBABILITY) ACROSS THE NORTHERN AND CENTRAL PARTS OF SONOMA
AND NAPA COUNTY THROUGH THE AFTERNOON, BUT MORE INTENSE SHOWERS AND
THUNDERSTORMS WILL BE LIMITED TO THE NORTHERN COAST RANGES AND THE
SIERRA NEVADA RANGE. FOR THE REST OF THE REGION, RAIN IS NOT
EXPECTED, ALTHOUGH MUGGY CONDITIONS WILL LINGER THROUGH THE DAY.
HIGH TEMPERATURES TODAY WILL HOVER IN THE MIDDLE 70S TO THE LOWER
80S INLAND, UP TO THE MIDDLE 80S IN THE WARMEST SPOTS OF SOUTHERN
MONTEREY COUNTY, THE UPPER 60S TO THE MIDDLE 70S ALONG THE BAYS, AND
THE MIDDLE TO UPPER 60S ALONG THE PACIFIC COAST.
TONIGHT THROUGH FRIDAY, THE UPPER LEVEL LOW THAT ENABLES THE
CONVECTIVELY-DRIVEN SHOWERS WILL DIMINISH AND MOVE OFF TO THE EAST,
WITH A RIDGE SETTING UP BEHIND THE LOW PRESSURE SYSTEM. THIS WILL
SHUT OFF OUR RAIN CHANCES FOR THE REST OF THE WEEK AND CONTRIBUTE TO
WARMING TEMPERATURES AND DRIER HUMIDITIES. HIGHS IN THE INLAND
VALLEYS WILL RISE TO THE UPPER 70S TO THE MIDDLE 80S, AND UP TO THE
UPPER 80S IN THE WARMEST LOCATIONS. THE REST OF THE REGION REMAINS
RELATIVELY STABLE.
LONG TERM
ISSUED AT 1204 PM PDT THU SEP 11 2025
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
CONDITIONS REMAIN DOMINATED BY THE NARROW BUT RATHER STOUT RIDGE ON
SATURDAY, BEFORE AN UPPER LEVEL TROUGH COMES IN FROM THE EASTERN
NORTH PACIFIC TO ERODE THE RIDGE ON SUNDAY. EARLIER FORECASTS HAD A
SLIGHT COOLDOWN AND A CHANCE FOR LIGHT RAIN IN THE BAY AREA ON
SUNDAY, BUT THE LATEST MODEL FORECASTS SHOW THAT THE TROUGH
INFLUENCE WILL NOT EXTEND AS FAR DOWN INTO THE STATE AS EARLIER
FORECASTS HAD INDICATED, RATHER KEEPING THE FLOW ZONAL AND THE BULK
OF THE TROUGH INFLUENCE IN THE PACIFIC NORTHWEST. THUS, WE ARE NO
LONGER EXPECTING ANY RAIN NOR MUCH OF A COOLDOWN ON SUNDAY. HEADING
INTO THE EARLY PART OF NEXT WEEK, RIDGING WILL START TO RETURN TO
THE REGION, WITH A UPPER LEVEL TROUGH OVER THE NORTHERN ROCKIES, AND
THE TEMPERATURES SHOULD SHOOT UP ABOVE SEASONAL AVERAGES. BY THE
MIDDLE OF NEXT WEEK, HIGHS WILL RANGE FROM THE UPPER 80S TO THE
MIDDLE 90S IN THE INLAND VALLEYS, AROUND 5 TO 12 DEGREES ABOVE
SEASONAL AVERAGES, WITH HIGHS IN THE UPPER 70S TO THE MIDDLE 80S
NEAR THE BAYS, AND EVEN THE PACIFIC COAST WARMING INTO THE LOWER
70S.
AVIATION
(06Z TAFS)
ISSUED AT 1003 PM PDT THU SEP 11 2025
LOW CLOUDS ARE FILLING THE BAYS AND ALONG THE COAST. IFR/MVFR
CIGS BECOME MOSTLY WIDESPREAD INTO THE NIGHT, WITH MOMENTS OF CIGS
EXPECTED FOR SJC, STS, AND LVK INTO FRIDAY MORNING, WHILE THE
REST OF THE TAF SITES SEE MORE CONSISTENT CIGS. CLOUD COVER WILL
BE SLOW TO ERODE ON FRIDAY, BUT NEARLY WIDESPREAD VFR IS EXPECTED
INT THE AFTERNOON. THE EXCEPTION, BEING HAF, WHICH SEES CIGS RISE
TO MVFR LEVELS, BUT DON'T CLEAR. FRIDAY AFTERNOON OFFERS ANOTHER
ROUND OF MODERATE TO BREEZY WINDS ARRIVE FRIDAY AFTERNOON 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...MVRF CIGS FILL OVER SFO INTO THE NIGHT AND STAY
IN PLACE THROUGH THE NIGHT AN INTO FRIDAY AFTERNOON. THESE CIGS
ERODE AS BREEZY WEST WINDS BUILD FRIDAY AFTERNOON, BUT CIGS RETURN
AS THE WINDS REDUCE INTO THAT NIGHT.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...MVFR CIGS ARE BUILDING AROUND THE THE BAY
AND WINDS ARE GETTING LIGHT. CIGS AT MRY AND SNS LOOK TO FALL TO
IFR LEVELS IN THE LATE NIGHT WITH WINDS BECOMING LIGHT AND
VARIABLE. CLOUD COVER ERODES INTO FRIDAY AFTERNOON AS MODERATE
WEST WIND BUILD. WINDS WEAKEN IN THE EARLY EVENING WITH CIGS
BUILDING.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 905 PM PDT THU SEP 11 2025
WINDS INCREASE ACROSS THE WATERS BECOMING BREEZY TO GUSTY FOR
FRIDAY. LOCALIZED STRONG GUSTS ARE POSSIBLE ACROSS THE NORTHERN
OUTER WATERS. MODERATE TO ROUGH SEAS DEVELOP FRIDAY AND PERSIST
INTO NEXT WEEK. CONDITIONS TEMPORARILY IMPROVE SATURDAY, AS WINDS
DECREASE AND SEAS EASE, BEFORE ANOTHER ROUND OF FRESH TO STRONG
NORTHWEST WINDS RETURNS 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 FROM 3 PM TO 9 PM PDT FRIDAY FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 9 AM FRIDAY TO 3 AM PDT SATURDAY FOR
PT ARENA TO PT REYES 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM FRIDAY TO 3 AM PDT SATURDAY FOR
PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...MURDOCK
MARINE...MURDOCK
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