184
FXUS66 KMTR 231843
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1143 AM PDT THU OCT 23 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1232 AM PDT THU OCT 23 2025
- NICE WEATHER THURSDAY - FRIDAY
- BENEFICIAL RAIN ACROSS THE BAY AREA THIS WEEKEND
- LARGE SWELL WILL RETURN FRIDAY WITH HAZARDOUS BEACH CONDITIONS
THROUGH THE WEEKEND
SHORT TERM
ISSUED AT 1232 AM PDT THU OCT 23 2025
(TODAY AND TONIGHT)
A SHORT WAVE RIDGE IS BUILDING AND WILL BE THE DOMINATE FEATURE IN
THE SHORT TERM, BRINGING FAIRLY TRANQUIL CONDITIONS. THE MARINE
LAYER IS REFORMING TONIGHT AND THE MOSTLY CLEAR SKIES WILL START
TO FILL IN WITH LOW STRATUS BY SUNRISE. THESE CLOUDS WILL CLEAR IN
THE LATE MORNING BEFORE A FANTASTIC AFTERNOON WITH CLEAR SKIES,
LIGHT WINDS, AND TEMPERATURES REACHING MID 70S INLAND WITH 60S
ALONG THE COAST. HIGH CLOUDS WILL PUSH IN FROM THE NORTH THROUGH
THE AFTERNOON. THESE CLOUDS ARE THE FIRST SIGNAL OF AN APPROACHING
CHANGE IN THE WEATHER PATTERN. IN THE MEANTIME, THEY SHOULD MAKE
FOR A NICE SUNSET TO END A PLEASANT DAY.
LONG TERM
ISSUED AT 1232 AM PDT THU OCT 23 2025
(FRIDAY THROUGH WEDNESDAY)
FRIDAY WILL BE SIMILAR TO THURSDAY, ALBEIT WITH MORE HIGH CLOUD
COVER SIGNALING THE APPROACHING COLD FRONT. THIS FRONT IS
SUPPORTED BY A TROUGH IN THE UPPER LEVELS THAT WILL PUSH OUT THE
RIDGE AND FLIP THE PATTERN FROM WARM AND DRY TO COOL AND WET BY
SATURDAY. THE CONFIDENCE IS HIGH IN THE GENERAL PATTERN THROUGH
THE WEEKEND, BUT THERE HAS BEEN SOME CHANGES IN THE DETAILS. IT
NOW LOOKS LIKE THE RAIN WILL ARRIVE LATER, AND WON'T BE AS WET AS
WE THOUGHT A COUPLE DAYS AGO. THE CURRENT FORECAST NOW HAS RAIN
REACHING THE NORTH BAY VERY EARLY SATURDAY MORNING RATHER THAN
LATE FRIDAY. THE TOTAL RAIN SHOULD BE AROUND 1/4-1/2" IN THE NORTH
BAY, WITH UP TO 1/10" ACROSS THE BAY AREA, AND A FEW HUNDREDTHS
ACROSS THE CENTRAL COAST. WHILE THE SYSTEM IS USHERING IN A
ROBUST PRE-FRONTAL TROPICAL MOISTURE PLUME IN THE SHAPE OF AN
ATMOSPHERIC RIVER, IT WILL MOVE VERY QUICKLY FROM N-S ON SATURDAY.
ENSEMBLES AGREE THAT THE PW WILL REACH BETWEEN 200-250% OF
NORMAL, BUT IN A THIN RIBBON THAT WILL PUSH THROUGH THE BAY AREA
AND CENTRAL COAST FROM SATURDAY MORNING THROUGH SATURDAY EVENING.
WHILE SHORT LIVED, MOST OF THE RAIN WILL COME FROM THIS FIRST
PUSH. SOME OF THE SHOWERS COULD BE HEAVY, BUT SHOULD BE BRIEF.
AFTER THE COLD FRONT MOVES THROUGH THERE MAY BE A 12 HOUR BREAK
BEFORE A WEAKER PUSH OF POSTFRONTAL SHOWERS ARRIVES SUNDAY AND
LINGERS INTO MONDAY. OUTSIDE OF RAIN, TEMPERATURES WILL BE COOLER
THIS WEEKEND WITH MOST AREAS STUCK IN THE 60S. THERE WILL ALSO BE
SOME GUSTY SW-W WINDS. WITH HIGH MOISTURE AND A FAST MOVING FRONT,
THUNDERSTORMS ARE POSSIBLE, BUT UNLIKELY. THE CHANCES ARE MAINLY
HELD BACK DUE TO PEDESTRIAN LAPSE RATES OF 4-6 C/KM. THE SKIES
SHOULD START TO CLEAR MONDAY AFTERNOON AS DRIER AIR SLOWLY FILTERS
IN. THE PW WILL STAY ABOVE NORMAL THROUGH MIDWEEK, BUT WITH
RIDGING ALOFT THE CHANCE FOR RAIN BASICALLY GOES TO ZERO BY
TUESDAY. THIS RIDGING LOOKS TO HAVE SOME STAYING POWER, AND
SHOULD KEEP DRY CONDITIONS AROUND THROUGH HALLOWEEN.
AVIATION
(18Z TAFS)
ISSUED AT 1143 AM PDT THU OCT 23 2025
LOW CLOUDS /MVFR/ CONTINUE ALONG A SHALLOW COOL FRONTAL BOUNDARY
ALONG THE COASTLINE OF THE BAY AREA WITH AN INLAND INTRUSION TAKING
PLACE TO THE EAST BAY, OTHERWISE VALLEY FOG /LIFR-IFR/ CONTINUES TO
MIX OUT AND VFR PREVAILS ELSEWHERE ACROSS THE FORECAST AREA. VFR
WILL GENERALLY PREVAIL THROUGH THE AFTERNOON WITH ONGOING MIXING.
THE COOL FRONT MOVES SOUTHWARD ALONG THE COASTLINE REACHING THE
NORTH CENTRAL COAST LATER IN THE AFTERNOON AND EVENING. LOW CLOUDS
AND VALLEY FOG /LIFR-IFR/ RETURN TONIGHT AND FRIDAY MORNING, MIXING
OUT BY LATE MORNING.
VICINITY OF SFO...MVFR CEILING CONTINUES WITH A WEST WIND NEAR 10
KNOTS UNTIL 21Z THEN INCREASING WEST WIND WITH GUSTS NEAR 20 KNOTS
FROM AFTERNOON TO MID EVENING. LOW CLOUDS /MVFR/ RETURN TONIGHT
AND FRIDAY MORNING, MIXING OUT 18Z FRIDAY.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR FOR THE LATE MORNING AND AFTERNOON,
THEN A QUICKLY MOVING, SHALLOW COOL FRONT SWEEPS BY DURING THE
LATE AFTERNOON. LOW CLOUDS /MVFR/ REDEVELOP IN THE EVENING MIXING
WITH FOG /LIFR-IFR/ DEVELOPMENT TONIGHT AND FRIDAY MORNING. LIGHT
AND VARIABLE WINDS TO LINGERING COOL AIR DRAINAGE WINDS IN THE
SALINAS VALLEY SHIFTING OVER TO ONSHORE NEAR 10 KNOTS, POSSIBLY A
FEW HIGHER GUSTS WITH THE SHALLOW COOL FRONTAL PASSAGE, DURING THE
LATE AFTERNOON AND EARLY EVENING.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 1129 AM PDT THU OCT 23 2025
A RIDGE OF HIGH PRESSURE WILL REMAIN OVER THE COASTAL WATERS
TODAY AND TONIGHT THEN WEAKEN BY LATE FRIDAY. AN ACTIVE, WET
WEATHER PATTERN REACHING THE PACIFIC NORTHWEST WILL PERIODICALLY
SEND FRONTAL SYSTEMS AS FAR SOUTH AS THE BAY AREA DURING THE
WEEKEND AND EARLY NEXT WEEK. ROUGH SEAS PREVAIL ACROSS THE WATERS,
BECOMING VERY ROUGH THIS WEEKEND. THERE'S A CHANCE OF SHOWERS
OVER THE NORTHERN WATERS BEGINNING SATURDAY MORNING AND LASTING
THROUGH THE WEEKEND. LONG PERIOD NORTHWESTERLY SWELL ENTERS THE
WATERS FRIDAY, PEAKING BY SUNDAY.
BEACHES
ISSUED AT 941 PM PDT WED OCT 22 2025
A MODERATE TO LONG PERIOD NORTHWESTERLY SWELL WILL RESULT IN
BREAKING WAVES OF 12 TO 17 FEET, WITH THE HIGHEST WAVES UP TO 25
FEET IN FAVORED LOCATIONS, AND AN INCREASED RISK FOR SNEAKER WAVES
AND RIP CURRENTS THROUGH THE NIGHT. SNEAKER WAVES CAN
UNEXPECTEDLY RUN SIGNIFICANTLY FARTHER UP THE BEACH THAN NORMAL,
INCLUDING OVER ROCKS AND JETTIES. RIP CURRENTS ARE TYPICALLY MORE
FREQUENT AND STRONGER IN THE VICINITY OF JETTIES, INLETS, AND
PIERS. SWIMMERS SHOULD ALWAYS SWIM NEAR A LIFEGUARD. REMAIN OUT OF
THE WATER TO AVOID HAZARDOUS SWIMMING CONDITIONS AND NEVER TURN
YOUR BACK ON THE OCEAN!
SARMENT
MTR WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT FROM LATE TONIGHT THROUGH LATE SUNDAY
NIGHT FOR CAZ006-505-509-529-530.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PT ARENA TO
PT REYES 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY 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.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT
SATURDAY FOR PIGEON PT TO PT PINOS 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...CANEPA
MARINE...CANEPA
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