638
FXUS66 KMTR 251455
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
655 AM PST TUE NOV 25 2025
..NEW UPDATE
KEY MESSAGES
UPDATED AT 144 PM PST MON NOV 24 2025
- DRY AND MILD CONDITIONS CONTINUE UNTIL THE END OF THE WEEK
- COOLER TEMPERATURES THIS WEEKEND AS THE NEXT SYSTEM APPROACHES
- GUSTY OFFSHORE WINDS ARE POSSIBLE BY THE END OF THE UPCOMING
WEEKEND
UPDATE
ISSUED AT 654 AM PST TUE NOV 25 2025
AREAS OF TO WIDESPREAD DENSE FOG CONTINUE TO IMPACT THE REGION THIS
MORNING ESPECIALLY IN THE NORTH BAY VALLEYS, EAST BAY VALLEYS,
SOUTHERN SALINAS VALLEY AND AROUND THE BAY SHORELINE WHERE WE NOW
HAVE A DENSE FOG ADVISORY THROUGH 11 AM PST. FOG IS ALSO IMPACTING
THE SAN FRANCISCO BAY, SAN PABLO BAY, AND THE WEST DELTA. SOME FOG
IS ALSO BEING REPORTED IN SAN JOSE WITH VISIBILITIES AT SJC HOLDING
AROUND 1/2 OF A MILE. CONDITIONS ARE FORECAST TO GRADUALLY IMPROVE
BEYOND 11 AM, YET ANYONE DRIVING SHOULD USE LOW BEAM HEADLINES AND
SLOW DOWN TO ALLOW EXTRA TIME TO REACH YOUR DESTINATION WHEN
ENCOUNTERING DENSE FOG. WE WILL CONTINUE TO MONITOR THE FOGGY
CONDITIONS CLOSELY THROUGHOUT THE MORNING.
RGASS
SHORT TERM
ISSUED AT 252 AM PST TUE NOV 25 2025
(TODAY AND TONIGHT)
PRIMARY CONCERN IN THE SHORT TERM IS THE DENSE FOG THAT HAS
DEVELOPED OVERNIGHT ACROSS THE NORTH BAY INTERIOR VALLEYS AND EAST
BAY INTERIOR VALLEYS, AND MAY EVENTUALLY HAVE TO BE EXPANDED FURTHER
AS WE HEAD TOWARD AND THROUGH SUNRISE. ATTM A DENSE FOG ADVISORY IS
IN EFFECT FOR THE NORTH BAY INTERIOR VALLEYS AND EAST BAY INTERIOR
VALLEYS UNTIL 11AM THIS MORNING.
AN OFFSHORE SURFACE HIGH PRESSURE UNDER BROADER RIDGING ALOFT IS
PULLING A WEAK FETCH OF OFFSHORE FLOW ACROSS MUCH OF OUR AREA TODAY
AND TOMORROW. SUBSIDENCE BENEATH THE RIDGE SHOULD KEEP A SHALLOW
MARINE LAYER JUST OFFSHORE THIS AFTERNOON AND EVENING AREA WIDE,
RESULTING IN A NICE DAY. TODAYS TEMPERATURES WILL BE SIMILAR TO
YESTERDAY FOR THE NORTH BAY AND BAY AREA, SLIGHTLY WARMER FOR INLAND
AREAS OVER THE CENTRAL COAST WHERE MORNING FOG WON'T BE AS
EXTENSIVE. PATCHY DENSE FOG IS EXPECTED TO DEVELOP ONCE AGAIN LATER
TONIGHT INTO THE OVERNIGHT HOURS OVER THE NORTH BAY INTERIOR
VALLEYS, HOWEVER COVERAGE SHOULD DECREASE AS DRIER AIR ASSOCIATED
WITH THE SHIFTING RIDGE MIXES CLOSER TO THE SURFACE.
LONG TERM
ISSUED AT 252 AM PST TUE NOV 25 2025
(WEDNESDAY THROUGH MONDAY)
GRADUAL WARMING THROUGH THE MIDDLE OF THE WEEK REMAINS ON TRACK WITH
TEMPERATURES PEAKING ON THURSDAY AFTERNOON WHILE A PROGRESSIVE
TROUGH TO OUR NORTH CONTINUES TO QUICKLY GET DEFLECTED NORTH AND
EAST OF OUR AREA. WEAK AMPLIFIED RIDGING ALOFT OVER THE PACIFIC
NORTHWEST ON FRIDAY WON'T STOP A WEAK BACK DOOR COLD FRONT FROM
PUSHING SOUTH THROUGH OUR AREA DURING THE DAY FRIDAY, COOLING MOST
AREAS OFF BY A FEW DEGREES. THE FORECAST FOR THE WEEKEND AND
BEYOND LACKS CONSENSUS, BUT COOLER TEMPERATURES THAN WHAT WE'LL
SEE THE NEXT FEW DAYS SEEMS LIKELY AS THE LONGWAVE SYNOPTIC
PATTERN BECOMES HIGHLY AMPLIFIED, ALLOWING FOR COOLER CANADIAN AIR
TO FILTER SOUTH ACROSS THE ENTIRE WEST COAST.
AVIATION
(12Z TAFS)
ISSUED AT 337 AM PST TUE NOV 25 2025
LIFR-VLIFR CONDITIONS HAVE DEVELOPED ACROSS THE NORTH BAY VALLEYS,
PARTS OF THE EAST BAY EXPOSED TO THE INFLUENCE OF THE CENTRAL VALLEY
FOG BANK, AND THE SOUTHERN REACHES OF THE SALINAS VALLEY. THE
CENTRAL VALLEY FOG HAS TAKEN ADVANTAGE OF DRAINAGE FLOWS AND HAS
DROPPED INTO PARTS OF THE SAN FRANCISCO BAY, WHERE SFO IS CURRENTLY
REPORTING AN IFR CEILING ALTHOUGH WITH GOOD SURFACE VISIBILITIES.
SOME FURTHER EXPANSION OF THE STRATUS IS POSSIBLE, PARTICULARLY AS
CLEAR SKIES ACROSS THE REST OF THE REGION PROMOTE RADIATIONAL
COOLING EFFECTS. LIGHT OFFSHORE FLOW WILL CONTINUE ACROSS THE REGION
THROUGH THE DAY, PROMOTING A CONTINUED FEED FROM THE CENTRAL VALLEY
FOG MINUS ANY SOLAR HEATING AND POTENTIALLY DELAYING CLEARANCE TIMES
ACROSS THE BAY AREA. THIS, IN TURN, COULD CONTINUE TO PROMOTE DENSE
FOG FORMATION TONIGHT INTO WEDNESDAY, ALTHOUGH THE EXACT DETAILS ARE
NOT CERTAIN AT THIS TIME.
VICINITY OF SFO... IFR CONDITIONS AT BEST THROUGH THE MORNING HOURS,
WITH THE SOUTHWEST FLOW HELPING STAVE OFF THE MOST SEVERE IMPACTS
FROM THE CENTRAL VALLEY FOG BANK. A MORE NORTHERLY FLOW DEVELOPING
THROUGH THE MORNING COULD BRING POOR VISIBILITIES TO THE TERMINAL.
STRATUS WILL TAKE QUITE A WHILE TO CLEAR OUT THIS MORNING WITH LIGHT
WINDS EXPECTED THROUGH THE DAY. THERE IS THE POTENTIAL FOR STRATUS
AND LOW FOG TO DEVELOP TONIGHT THROUGH WEDNESDAY MORNING, WHICH IS
NOT BEING CAPTURED VERY WELL BY THE HIGH RESOLUTION MODELS. HAVE
KEPT THE TAF ABOVE IFR FOR NOW, BUT PILOTS SHOULD KEEP TRACK OF TAF
UPDATES AS THE DAY EVOLVES IN CASE THE CHANCES FOR FOG INCREASE.
SFO BRIDGE APPROACH... SIMILAR TO SFO.
MONTEREY BAY TERMINALS... LOW TO MODERATE CONFIDENCE OF VFR
CONDITIONS THROUGH THE TAF PERIOD. CLEAR SKIES AND DRY OFFSHORE
FLOWS CAN PROMOTE RADIATIONAL COOLING, BUT THE WINDS ALSO MIX THE
LOWER LAYERS AND PREVENT STRATUS FROM FORMING THROUGH THE MORNING.
VFR CONDITIONS CONTINUES THROUGH THE LATE AFTERNOON WITH WINDS
SHIFTING TO A LIGHT ONSHORE FLOW.
MARINE
(TODAY THROUGH SUNDAY)
ISSUED AT 252 AM PST TUE NOV 25 2025
DENSE FOG HAS DEVELOPED ACROSS THE WEST DELTA, INTO THE SAN PABLO
AND SAN FRANCISCO BAYS, CREATING HAZARDOUS CONDITIONS FOR
MARINERS THROUGH THE MORNING HOURS. HIGH PRESSURE WILL PERSIST
OVER THE COASTAL WATERS THROUGH MID TO LATE WEEK. SEAS WILL
GRADUALLY EASE THROUGH THE MIDDLE OF THE WEEK WITH GENTLE TO
MODERATE NORTHERLY BREEZES. WINDS WILL BEGIN TO INCREASE AGAIN
LATE WEEK, BUILDING MODERATE TO ROUGH SEAS.
BEACHES
ISSUED AT 923 PM PST MON NOV 24 2025
THE BEACH HAZARDS STATEMENT HAS BEEN EXTENDED THROUGH 10 AM PST
TUESDAY. A LONG PERIOD NORTHWESTERLY SWELL WILL RESULT IN AN
INCREASED RISK FOR SNEAKER WAVES AND RIP CURRENTS. BREAKING WAVES
OF 13 TO 18 FEET ARE EXPECTED. 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.
MTR WATCHES/WARNINGS/ADVISORIES
CA...DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR CAZ006-506-
508-510-516.
BEACH HAZARDS STATEMENT UNTIL 10 AM PST THIS MORNING FOR CAZ006-
505-509-529-530.
PZ...DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR SF BAY N OF
BAY BRIDGE.
SHORT TERM...JM
LONG TERM....JM
AVIATION...DIALH
MARINE...DIALH
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