510
FXUS66 KMTR 311748
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1048 AM PDT FRI OCT 31 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 212 AM PDT FRI OCT 31 2025
- NICE AND QUIET WITH WARM TEMPS THROUGH THIS WEEKEND.
- COOLER TEMPS (NEAR AVERAGE) BY THE START OF NEXT WEEK.
- CONFIDENCE INCREASING ON THE NEXT RAIN MAKER, SET TO ARRIVE BY
THE MIDDLE OF NEXT WEEK.
UPDATE
ISSUED AT 913 AM PDT FRI OCT 31 2025
LOW CLOUDS AND PATCHY FOG ARE BEING OBSERVED THIS MORNING ACROSS
MOST OF THE REGION OUTSIDE OF THE HIGHER ELEVATIONS WHERE WEAK
OFFSHORE FLOW CONTINUES. HOWEVER, FOG IS NOT AS WIDESPREAD THIS
MORNING COMPARED TO YESTERDAY. CLOUDS AND/OR FOG WILL BEGIN TO
DISSIPATE BY LATE THIS MORNING AND WILL CONTINUE THROUGH THE EARLY
AFTERNOON AS TEMPERATURES WARM INTO THE 70S INLAND (AND SANTA CRUZ
AREA) AND 60S NEAR THE IMMEDIATE COASTLINE. NO UPDATES ANTICIPATED
TO THE ONGOING FORECAST AT THIS TIME.
RGASS
SHORT TERM
ISSUED AT 212 AM PDT FRI OCT 31 2025
(TODAY AND TONIGHT)
PLEASANT AND QUIET CONDITIONS ON TAP TODAY AS LONGWAVE RIDGING
DOMINATES THE PATTERN OVER THE WESTERN US. MORE OF A SUMMER-TIME
PATTERN FOR US WITH FOG AND STRATUS MIXING OUT AFTER SUNRISE AND
RETURNING TONIGHT WITH A WELL-FORMED MARINE LAYER REMAINING INTACT
THROUGH THE DAY. HIGHS TODAY ABOUT 5-10 DEGREES ABOVE NORMAL.
LONG TERM
ISSUED AT 212 AM PDT FRI OCT 31 2025
(SATURDAY THROUGH THURSDAY)
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
(18Z TAFS)
ISSUED AT 1048 AM PDT FRI OCT 31 2025
SIMILAR TO THURSDAY MORNING, SATELLITE AND OBSERVATIONS SHOW AREAS
OF STRATUS AND FOG /MVFR-IFR-LIFR/ OTHERWISE EXPECT VFR WITH MIXING
OCCURRING THROUGH LATE MORNING AND AFTERNOON. STRATUS AND FOG /IFR-
LIFR/ RETURN TONIGHT INTO SATURDAY MORNING.
VICINITY OF SFO...IFR UNTIL 19Z THEN VFR THROUGH THE AFTERNOON AND
EVENING. WEST TO NORTHWEST WIND NEAR 10 KNOTS INCREASING TO 15 TO 20
KNOTS THIS AFTERNOON AND EARLY EVENING. WEST WIND 7 TO 12 KNOTS FROM
MID EVENING TO SATURDAY.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR MIXING OUT THROUGH LATE MORNING THEN
VFR DURING THE AFTERNOON. STRATUS AND FOG/MIST /IFR-LIFR/ RETURN
TONIGHT AND SATURDAY MORNING. ONSHORE WINDS 5 TO 10 KNOTS DURING
THE AFTERNOON AND EARLY EVENING BECOMING LIGHT EAST TO SOUTHEAST
TONIGHT AND SATURDAY MORNING.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 913 AM PDT FRI OCT 31 2025
FRESH TO STRONG NORTHERLY BREEZES WILL PREVAIL THROUGH THE
WEEKEND, DIMINISHING TO BECOME MODERATE TO FRESH EARLY NEXT WEEK.
MODERATE TO ROUGH SEAS WILL PREVAIL WITH VERY ROUGH SEAS EXPECTED
IN THE OUTER WATERS THIS WEEKEND. UNSETTLED WEATHER WITH RAIN AND
WIND RETURNS LATE TUESDAY NIGHT.
BEACHES
ISSUED AT 410 AM PDT FRI OCT 31 2025
A LONG PERIOD NORTHWESTERLY SWELL WILL BRING AN INCREASED RISK
FOR SNEAKER WAVES AND RIP CURRENTS AND BREAKING WAVES OF 12-17
FEET TO PACIFIC COAST BEACHES SATURDAY THROUGH MONDAY. 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 SATURDAY MORNING THROUGH LATE
MONDAY NIGHT FOR CAZ006-505-509-529-530.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT
SATURDAY FOR PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT SATURDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...BEHRINGER
LONG TERM....BEHRINGER
AVIATION...CANEPA
MARINE...CANEPA
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