671
FXUS66 KMTR 251054
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
254 AM PST TUE NOV 25 2025
..NEW SHORT TERM, LONG TERM, MARINE
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
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
(06Z TAFS)
ISSUED AT 938 PM PST MON NOV 24 2025
CONDITIONS VARY FROM VFR TO LIFR INCLUDING A FEW AREAS OF HAZY
SKIES THIS EVENING. A SHALLOW COOL FRONTAL BOUNDARY IS MOVING
SOUTHWARD OVER THE COASTAL WATERS WHILE LOW CEILINGS, FOG AND TULE
FOG ARE SLOWLY ADVANCING BACK INTO OUR EASTERNMOST FORECAST AREA.
A STABLE AIR MASS INCLUDING A LOWER PRECIPITABLE WATER (0.52") ON
THE 00Z (4 PM) OAKLAND UPPER AIR SOUNDING COMPARED TO 0.72" 12Z
(4 AM) THIS MORNING FAVORS IMPROVING RADIATIVE COOLING TONIGHT AND
TUESDAY MORNING. LIGHT OFFSHORE WINDS PER SAC-SFO 0.8 MB AND WMC-
SFO 2.1 MB SUPPORT A REVERSAL OF MARITIME INFLUENCE WE HAD OVER
THE WEEKEND (WHICH HELPED LIMIT DENSE FOG COVERAGE), WITH AN
INCREASING CONTINENTAL INFLUENCE REACHING INTO OUR FORECAST AREA,
INCLUDING A TULE FOG INTRUSION FROM THE EAST TONIGHT AND TUESDAY
MORNING. SO FAR NOT SEEING ANY NUMERICAL WEATHER PREDICTION
MESOSCALE MODELS SHOWING ANY SIGNIFICANT BOUNDARIES FORECAST TO
DISRUPT THE LIGHT OFFSHORE WIND PATTERN TUESDAY MORNING WHICH MAY
ALLOW THE FOG INTRUSION TO THE BAY AREA TO LINGER DURING THE DAY,
MINUS INCOMING SOLAR HEATING TUESDAY. THIS MAY FAVOR A POSITIVE
FEEDBACK LOOP OF MORE DENSE FOG TUESDAY NIGHT/WEDNESDAY MORNING.
VICINITY OF SFO...VFR LIKELY CONTINUES THROUGH THE EVENING. THERE'S
AN INCREASING PROBABILITY 20%-30% OF IFR PER RECENT HREF BETWEEN
09Z-16Z TUESDAY, 00Z/06Z SFO TAF HAS TEMPO IFR CEILING 13Z-17Z
TUESDAY, BUT CAVEAT IS PERSISTENT LIGHT NE-E WIND MAY TRANSPORT
EVEN LOWER CONDITIONS TO VLIFR-LIFR DURING THIS TIME. IT'S A LOW
CONFIDENCE FORECAST SINCE IT'S STILL MANY HOURS FROM NOW, HOWEVER
WEATHER CONDITIONS AND THE TIME OF YEAR (PLUS RECENT GENEROUS EARLY
SEASON RAIN) ARE ALL FAVORABLE FOR AFOREMENTIONED CONDITIONS AND
IT NEEDS TO BE CLOSELY MONITORED. AS SUCH, IT IS A LOW CONFIDENCE
FORECAST AS TO THE RETURN AND DURATION OF VFR TUESDAY, IF THE
MODEL FORECASTS ARE UNDER-FORECASTING THE EXTENT OF FOG IT MAY
TAKE LONGER TO MIX OUT TO VFR THAN CURRENTLY 17Z ADVERTISED IN THE
TAF.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...LOW TO MODERATE CONFIDENCE VFR CONTINUES
THROUGH LATE EVENING AND OVERNIGHT HERE. CURRENT SATELLITE IMAGERY
SUPPORTS VFR FORECAST TO LATE EVENING AT LEAST. NOCTURNAL RADIATIVE
COOLING WILL SET UP COOL AIR DRAINAGE WINDS FOR TONIGHT AND TUESDAY
MORNING PROVIDING A MIXING WIND TO HELP PREVENT THE DEVELOPMENT OF
STRATUS AND/OR FOG. COOL FRONT AND AIR MASS PASSES BY TO OUR WEST,
HREF/HRRR MODEL OUPUT SHOW DRY, COOL AIR DRAINAGE MIXING WINDS AND
VFR PREVAILING TONIGHT AND TUESDAY MORNING. VFR CONTINUES TUESDAY
AFTERNOON WITH WINDS GENTLY SHIFTING BACK TO LIGHT ONSHORE IN THE
MID TO LATE AFTERNOON. LOW CONFIDENCE VFR FORECAST TUESDAY EVENING.
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...BEACH HAZARDS STATEMENT UNTIL 10 AM PST THIS MORNING FOR CAZ006-
505-509-529-530.
DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR CAZ506-510.
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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