203
FXUS66 KMTR 010505
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1005 PM PDT FRI OCT 31 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1229 PM PDT FRI OCT 31 2025
- NICE AND QUIET WITH WARM TEMPERATURES THROUGH THIS WEEKEND.
- COOLER TEMPERATURES (NEAR AVERAGE) BY THE START OF NEXT WEEK.
- CONFIDENCE INCREASING ON THE NEXT RAIN MAKER, SET TO ARRIVE BY
THE MIDDLE OF THE UPCOMING WEEK.
UPDATE
ISSUED AT 912 PM PDT FRI OCT 31 2025
OVERALL, THE SHORT TERM FORECAST IS IN GOOD SHAPE, WITH JUST A FEW
COSMETIC CHANGES NEEDED TO THE WEATHER GRIDS. STRATUS CONTINUES TO
GRADUALLY BUILD AFTER BEING BRIEFLY INTERRUPTED BY A DEPARTING
UPPER TROUGH. I ANTICIPATE THAT COASTAL AREAS WILL BE INUNDATED
WITH LOW CLOUDS AND OCCASIONAL FOG. DEWPOINT DEPRESSIONS ARE
RUNNING ANYWHERE FROM 2 TO 5 DEGREES HIGHER THAN 24 HOURS AGO AND
THIS MAY BE THE LIMITING FACTOR FOR A MORE WIDESPREAD FOG EVENT.
STILL, SOME OF THE FAVORED RIVER VALLEYS AND SHELTERED LOCATIONS
WILL HAVE THE POTENTIAL FOR PATCHY FOG, SOME DENSE IN SPOTS, SO BE
MINDFUL IF OUT COMMUTING EARLY SATURDAY MORNING. OTHERWISE, WE'LL
CONTINUE TO MONITOR THE POTENTIAL FOR OUR NEXT WEATHER SYSTEM
SLATED TO IMPACT THE AREA TOWARD THE BEGINNING TO MIDDLE OF NEXT
WEEK. IN ADDITION, THERE WILL BE SOME COASTAL FLOOD IMPACTS DUE TO
HIGHER THAN NORMAL TIDES GOING INTO NEXT WEEK. ADDITIONAL DETAILS
WILL BE FORTHCOMING IN THE NEXT 1-2 DAYS.
SHORT TERM
ISSUED AT 1229 PM PDT FRI OCT 31 2025
(THIS EVENING THROUGH SATURDAY)
AS LOW CLOUDS BEGIN TO GIVE WAY TO CLEAR SKIES THIS AFTERNOON,
TEMPERATURES ARE FORECAST TO WARM INTO THE 70S ACROSS INLAND AREAS
(AND THE SANTA CRUZ REGION) WITH 60S NEAR THE COAST. HOWEVER, WHERE
LOW CLOUDS LINGER, TEMPERATURES WILL NOT WARM AS MUCH AS PREVIOUSLY
FORECAST. LOW CLOUDS HAVE THE POTENTIAL TO RETURN TONIGHT, MORE
TYPICAL OF A SUMMER-TIME PATTERN AS A WELL DEFINED AS THE MARINE
LAYER IS FORECAST TO COMPRESS SLIGHTLY, RESULTING IN LESS INLAND
INTRUSION.
TEMPERATURES TONIGHT WILL COOL DOWN TO THE UPPER 40S ACROSS THE
NORTH BAY AND INTERIOR PORTIONS OF THE CENTRAL COAST WITH LOW TO MID
50S ELSEWHERE. ANY LOW CLOUDS AND/OR FOG THAT DO DEVELOP WILL MIX
OUT BY LATE SATURDAY MORNING. AS SUCH, TEMPERATURES SATURDAY
AFTERNOON ARE FORECAST TO BE A BIT WARMER. EXPECTING TEMPERATURES TO
APPROACH 80 DEGREES F IN THE NORTH BAY, EAST BAY, SOUTH BAY AND
INTERIOR AREAS OF THE CENTRAL COAST. THIS WILL BE THE RESULT OF A
SHORT-WAVE RIDGE BUILDING ACROSS SOUTHERN CALIFORNIA AHEAD OF AN
APPROACHING TROUGH WELL TO THE NORTH.
LONG TERM
ISSUED AT 1229 PM PDT FRI OCT 31 2025
(SATURDAY NIGHT THROUGH NEXT THURSDAY)
FOR SUNDAY, EXPECTING THE SAME WEATHER PATTERN AS SATURDAY. NO CLEAR
SINGLE ONE WAY OR ANOTHER FOR THE MONDAY-WEDNESDAY WITH RESPECT TO
RAINFALL. THUS, THOUGHT THE PREVIOUS FORECASTER SUMMED UP THE REST
OF THE LONG TERM DISCUSSION RATHER WELL: "BEYOND THE WEEKEND IS WHEN
WE START TO FIND THE NEXT THING WORTH TALKING ABOUT. MEDIUM-RANGE
GUIDANCE HAS BEEN ADVERTISING A NOTABLE PATTERN CHANGE WITH A DEEP
UPPER LOW IN THE GULF OF ALASKA HELPING TO ERODE THE DOWNSTREAM
RIDGE. THIS OPENS THE DOOR FOR A ROBUST 150 KT PACIFIC JET ACROSS
THE ALEUTIANS TO PROMOTE ANOTHER DEEP UPPER LOW DIGGING INTO THE
EPAC OFF THE WEST COAST. THIS WILL BE OUR STORM TO WATCH. CONFIDENCE
IS INCREASING FOR IMPACTFUL RAINFALL IN THE NORTH BAY ON WEDNESDAY.
ENSEMBLE CLUSTER ANALYSIS SHOWS THAT APPROX 74% OF MEMBERS ADVERTISE
RAINFALL AMOUNTS GREATER THAN THE ENSEMBLE MEAN. ESSENTIALLY WHAT
THIS MEANS IS THAT THERE IS BETTER AGREEMENT ON THE HIGHER END OF
THE MODEL SPREAD. WHAT IS THIS SPREAD? GREAT QUESTION. THE 25TH-75TH
PERCENTILES FOR THE NORTH BAY ARE RUNNING ABOUT 0.75"-1.75" ON
AVERAGE (24 HOUR TOTALS, AND GIVE OR TAKE A HALF INCH DEPENDING ON
WHERE YOU ARE IN THE COUNTY). SURE, NOT OUTSTANDING FOR THE NORTH
BAY, BUT AT LEAST THIS TELLS US THAT WE MAY BE IN FOR A DECENT
RAINFALL. POTENTIALLY THE MOST WE'VE SEEN THIS SEASON IN THOSE
PARTS. THINGS ARE MORE UNCERTAIN FOR THE REST OF THE BAY AREA AND
CENTRAL COAST. THERE IS NOT ENOUGH CERTAINTY HERE TO GIVE A
MEANINGFUL FORECAST AT THIS POINT, BUT AT THE VERY LEAST EXPECT SOME
RAIN AND WIND. MORE ON THE WIND...AS THE TROUGH SWINGS THROUGH ON
WEDNESDAY, WE'LL LIKELY SEE WIDESPREAD IMPACTFUL WINDS ASSOCIATED
WITH THE PASSAGE OF THE UPPER LEVEL JET CORE. CURRENT MODEL GUIDANCE
HINTS AT A DECENT CHANCE OF SEEING 50 KTS AT 850 MB, WHICH WOULD BE
NEAR THE DAILY RECORD MAX FOR THIS TIME OF YEAR. AGAIN, NOTHING
COMPARED TO STRONGER STORMS THAT WE MAY SEE IN DECEMBER-FEBRUARY,
BUT FAIRLY RESPECTABLE FOR THIS POINT IN THE SEASON."
AVIATION
(06Z TAFS)
ISSUED AT 1005 PM PDT FRI OCT 31 2025
VFR CONDITIONS AT THE MOMENT, BUT A STRATUS DECK LURKS OFF THE COAST
AND IS EXPECTED TO BEGIN IMPACTING THE COASTAL TERMINALS IMMINENTLY.
CONFIDENCE IN STRATUS IMPACTS IN THE INTERIOR HAS DECREASED, AND THE
STS AND LVK TERMINALS ARE NOW VFR. THERE IS STILL A RATHER LOW
PROBABILITY OF RADIATIVE STRATUS AT THE TERMINALS, WITH THE BEST
CHANCES BETWEEN 12Z AND 16Z. THE STRATUS SHOULD MIX OUT THROUGH
SATURDAY MORNING, WITH BREEZY ONSHORE WINDS DEVELOPING IN THE
AFTERNOON AND EVENING.
VICINITY OF SFO... VFR CONDITIONS AT PRESENT AT THE TERMINAL. HIGH
RESOLUTION MODELS CONTINUE TO DEPICT STRATUS DEVELOPING TO THE NORTH
AND EAST OF THE TERMINAL, INCLUDING OAK. AT SFO ITSELF IT LOOKS TO
BE QUITE A CLOSE CALL. CURRENTLY SEEING A 20-30% PROBABILITY THAT
STRATUS FORMS AT THE TERMINAL TONIGHT. AFTER SOME DELIBERATION,
ADDED A TEMPO GROUP FROM 12Z TO 16Z IN CASE RADIATIONAL EFFECTS AND
STRATUS FLOW COMBINE TO PRODUCE STRATUS. ANY CLOUDS THAT FORM SHOULD
CLEAR OUT SATURDAY MORNING WITH BREEZY WEST-NORTHWEST WINDS IN THE
AFTERNOON AND EVENING HOURS.
SFO BRIDGE APPROACH... SOMEWHAT HIGHER CONFIDENCE IN LIMITED STRATUS
IMPACTS ALONG THE APPROACH PATH, ESPECIALLY CLOSE TO THE SOUTHERN
END. OTHERWISE SIMILAR TO SFO.
MONTEREY BAY TERMINALS... TERMINALS REMAIN VFR AT PRESENT WITH LIFR
STRATUS ARRIVING AFTER MIDNIGHT. LIGHT DRAINAGE FLOW EXPECTED
OVERNIGHT BEFORE BREEZY ONSHORE WINDS RESUME SATURDAY AFTERNOON.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 1005 PM PDT FRI OCT 31 2025
FRESH TO STRONG NORTHWEST BREEZES AND MODERATE TO ROUGH SEAS WILL
CONTINUE THROUGH THE WEEKEND. HIGH PRESSURE WEAKENS EARLY NEXT
WEEK FOLLOWED BY AN ENERGETIC PACIFIC PATTERN BRINGING RAIN AND
WIND TO OUR COASTAL WATERS AND BAYS FROM LATE TUESDAY THROUGH
WEDNESDAY NIGHT.
BEACHES
ISSUED AT 912 PM PDT FRI OCT 31 2025
A LONG PERIOD NORTHWESTERLY SWELL WILL BRING AN INCREASED THREAT
FOR FOR SNEAKER WAVES, RIP CURRENTS, AND BREAKING WAVES OF 12-17
FEET TO PACIFIC COAST BEACHES THROUGH MONDAY. SUBSEQUENT FORECASTS
WILL PROVIDE UPDATES TO BREAKING WAVE HEIGHTS. 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/BAIN
MTR WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT FROM 7 AM PDT SATURDAY THROUGH LATE
MONDAY NIGHT FOR CAZ006-505-509-529-530.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PIGEON PT TO PT
PINOS 0-10 NM-PT ARENA TO PT REYES 0-10 NM-PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PDT SATURDAY FOR PIGEON
PT TO PT PINOS 0-10 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10
NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SUNDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...RGASS
LONG TERM....RGASS
AVIATION...DIALH
MARINE...DIALH
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