741
FXUS66 KMTR 251807
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1107 AM PDT SUN OCT 25 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1207 AM PDT SUN OCT 25 2026
- SEASONABLY WARM CONDITIONS TODAY
- COOL CONDITIONS THROUGH THE NEXT WEEK
- RAIN CHANCES LATE WEEK INTO THE UPCOMING WEEKEND
- MINOR COASTAL FLOODING AT HIGH TIDE FOR BAYSHORE LOCATIONS
THROUGH THE WEEK
SHORT TERM
ISSUED AT 1207 AM PDT SUN OCT 25 2026
(TODAY AND TONIGHT)
SATELLITE IMAGERY REVEALS MOSTLY CLEAR SKIES ACROSS THE REGION SAVE
FOR A PATCH OF STRATUS THAT HAS DEVELOPED NEAR BODEGA BAY AND DILLON
BEACH AND A LITTLE BIT EASTWARD THROUGH THE PETALUMA GAP. SKIES
SHOULD REMAIN MOSTLY CLEAR THROUGH THE NEXT DAY, BARRING ANY
RADIATIONAL STRATUS AND FOG THAT DEVELOPS WITHIN THE NORTH BAY
EARLY IN THE MORNING, WHICH SHOULD DISSIPATE AFTER SUNRISE.
A WARM PERIOD CONTINUES ACROSS THE REGION AS A SHORTWAVE RIDGE
SANDWICHED BETWEEN A DEPARTING LOW MOVING INTO THE DESERT SOUTHWEST
AND AN DEVELOPING ONE OFF THE COAST OF BRITISH COLUMBIA AND THE
PACIFIC NORTHWEST. HIGHS REMAIN SEASONABLY WARM WITH HIGHS IN THE
LOWER TO MIDDLE 70S EXPECTED ACROSS THE INLAND VALLEYS, HIGHS IN
THE UPPER 70S ACROSS THE WARMEST SPOTS OF THE SOUTHERN SALINAS
VALLEY AND THE MORGAN HILL-GILROY AREA, THE UPPER 60S TO LOWER 70S
CLOSE TO THE BAYS, AND THE UPPER 50S TO MIDDLE 60S ALONG THE PACIFIC
COAST. A GENTLE ONSHORE BREEZE SHOULD DEVELOP IN THE AFTERNOON, WITH
GUSTS TO 20 MPH POSSIBLE WITHIN THE SALINAS VALLEY.
A COMBINATION OF HIGH ASTRONOMICAL TIDES AND SURGE FROM THERMAL
EXPANSION EFFECTS BRINGS THE RISK OF MINOR COASTAL FLOODING ACROSS
BAYSHORE LOCATIONS WITHIN THE SAN PABLO BAY, SAN FRANCISCO BAY, AND
MONTEREY BAY AT HIGH TIDE TODAY. AT THE SAN FRANCISCO TIDAL GAUGE,
HIGH TIDE IS EXPECTED TO BE 1.5 FT ABOVE NORMAL (7.3 FT MLLW) AT
11:07 AM SUNDAY 10/25, INCLUDING AROUND 1.0 FT OF SURGE RESIDUAL
PARTIALLY ATTRIBUTED TO IMPACTS FROM EL NINO.
LONG TERM
ISSUED AT 1207 AM PDT SUN OCT 25 2026
(MONDAY THROUGH SATURDAY)
LARGE-SCALE TROUGHING PERSISTS ACROSS THE WESTERN US AS A LOW MOVES
ACROSS THE PACIFIC NORTHWEST, AND BY THE MIDDLE OF THE WEEK, A
SECOND DEVELOPING LOW OVER BRITISH COLUMBIA WILL INTERACT WITH A
DECAYING LOW MOVING IN FROM THE CENTRAL PACIFIC TO REINFORCE THE
TROUGHING. SOME LIGHT SPRINKLES ARE POSSIBLE IN THE NORTHERN COASTAL
WATERS AND THE ADJACENT AREAS OF THE NORTH BAY ON MONDAY MORNING AS
THE LOW PASSES BY, BUT MOST OF THE IMPACTS WILL BE FELT ALONG THE
NORTH COAST AND ACROSS OREGON. OTHERWISE, HIGHS WILL START TO DIP
FOR THE WORK WEEK, WITH HIGHS IN THE INLAND VALLEYS DROPPING TO THE
MIDDLE TO UPPER 60S BY MONDAY AND THE LOWER TO MIDDLE 60S FOR THE
SECOND HALF OF THE WEEK.
THE END OF THE WEEK INTO THE UPCOMING WEEKEND IS WHERE THINGS GET
INTERESTING IN TERMS OF THE FORECAST, FOR IT IS WHERE THE MODEL
OUTPUTS START TO DIVERGE AND THE RESULTING UNCERTAINTY RATCHETS
UPWARD. COMPARING MEAN OUTPUTS FROM TWO OF THE GLOBAL ENSEMBLE
MODELS REVEALS A REMARKABLY DIFFERENT SOLUTION ACROSS THE WESTERN
UNITED STATES. THE EUROPEAN ECMWF ENSEMBLE MODEL MEAN SUGGESTS THAT
THE TROUGH WILL CONTINUE HANDING ON THROUGH THE UPCOMING WEEKEND
WHILE THE AMERICAN GEFS ENSEMBLE MODEL MEAN DEPICTS A SLIGHT RIDGE
COMING IN AND BREAKING UP THE TROUGH'S INFLUENCE BY NEXT SUNDAY, THE
FIRST DAY OF NOVEMBER. ENSEMBLE MODEL CLUSTER ANALYSIS FOR DAY 7
(SATURDAY) REINFORCES THIS SPLIT BETWEEN A MORE TROUGH-INFLUENCED
SOLUTION FROM THE EUROPEAN ENSEMBLE MEMBERS, AND A MORE RIDGE-
INFLUENCED SOLUTION FROM THE AMERICAN ENSEMBLE MEMBERS, WITH THE
MEMBERS OF THE CANADIAN GEPS ENSEMBLE MODEL SPLIT BETWEEN THE TWO
WITH A SLIGHT LEAN TOWARDS THE AMERICAN ENSEMBLE SOLUTION. AS A SIDE
NOTE, THIS WHOLE DISCUSSION MAY ILLUMINATE WHY MODEL OUTPUT AROUND
AND BEYOND 200 HOURS IS GENERALLY CONSIDERED UNRELIABLE BY THOSE.
THE CURRENT FORECAST SHOWS RAIN CHANCES COMING IN FRIDAY INTO THE
UPCOMING WEEKEND, BUT WITH THE SPLIT BETWEEN THE MODELS THAT'S
PRETTY MUCH ALL THAT CAN BE SAID WITH EVEN A MODERATE DEGREE OF
CONFIDENCE. WE WILL KEEP A CLOSE EYE ON THE FORECAST, NOT LEAST
BECAUSE IT COULD DETERMINE WHETHER PEOPLE NEED TO CONSIDER PONCHOS
OR UMBRELLAS AS PART OF THEIR HALLOWEEN PLANS.
COASTAL FLOODING CONCERNS CONTINUE ACROSS BAYSHORE LOCATIONS WITHIN
THE SAN PABLO, SAN FRANCISCO, AND MONTEREY BAYS THROUGH THE NEXT
WEEK, AND WILL EXPAND INTO THE PACIFIC COASTAL REGIONS BY MONDAY
THROUGH FRIDAY. AT THE SAN FRANCISCO TIDAL GAUGE, HIGH TIDE IS
EXPECTED TO BE 1.6 FT ABOVE NORMAL (7.4 FT MLLW) AT 11:39 AM MONDAY
10/26, 1.8 FT ABOVE NORMAL (7.6 FT MLLW) AT 12:15 PM TUESDAY 10/27,
1.9 FT ABOVE NORMAL (7.7 FT MLLW) AT 12:56 PM WEDNESDAY 10/28, 1.7
FT ABOVE NORMAL (7.5 FT MLLW) AT 01:43 PM THURSDAY 10/29, 1.4 FT
ABOVE NORMAL (7.2 FT MLLW) AT 2:39 PM ON FRIDAY 10/30, AND 1.0 FEET
ABOVE NORMAL (6.8 FT MLLW) AT 3:44 PM ON SATURDAY 10/31, INCLUDING
AROUND 1.0 FT OF SURGE RESIDUAL PARTIALLY ATTRIBUTED TO IMPACTS FROM
EL NINO.
AVIATION
(18Z TAFS)
ISSUED AT 1105 AM PDT SUN OCT 25 2026
ANOTHER VFR DAY IS ON TAP FOR THE REGION, WITH SATELLITE SHOWING
ONLY HIGH CLOUDS STREAMING OVER US. TONIGHT, THE UPPER LEVEL TROUGH
WILL CONTINUE TO TRACK ACROSS THE PACNW WHILE TROUGHING EXTENDS
SOUTH. THIS WILL ALLOW FOR ONSHORE FLOW TO TAKE HOLD OF MUCH OF THE
REGION AND PERHAPS INTERACT WITH THE MARINE LAYER. RIGHT NOW THE
MOST LIKELY SITES TO SEE ANY MARINE LAYER ACTION OR STRATUS SEEM TO
BE AROUND THE SAN FRANCISCO/SAN MATEO PENINSULA AND AROUND THE
MONTEREY BAY. THOUGH CONFIDENCE IS MODERATE, SO OPTED TO KEEP THE
HINT OF LOWER CLOUDS IN THE FORECAST RATHER THAN SOCKING AREAS IN.
SHOULD WE SEE LOW CLOUDS DEVELOP, THE TIMING IS CURRENTLY BETWEEN 6Z-
15Z WITH CLOUDS LIFTING OR MIXING OUT BY THE LATE MORNING.
VICINITY OF SFO...QUIET CONDITIONS CONTINUE AS HIGH CLOUDS STREAM
OVERHEAD. WINDS ARE EXPECTED TO BECOME ONSHORE LATER THIS
AFTERNOON, PEAKING BETWEEN 10-15 KT, BEFORE DECREASING TO LESS THAN
10 KT DURING THE OVERNIGHT HOURS. AS MENTIONED ABOVE THERE IS SIGNAL
FOR SOME LOWER CLOUDS TO MOVE INTO THE SFO REGION, RIGHT NOW MODELS
GENERALLY KEEP IT WEST OF THE TERMINAL AND CLOSER TO THE COAST. KEPT
THE HINT OF MVFR CIGS IN THE TAF AS A RESULT, WITH CLOUDS LIFTING TO
VFR CIGS BY LATE MORNING. TOMORROW AFTERNOON, A STRONG PUSH OF
ONSHORE WINDS IS FORECAST. THIS WILL BE CLOSE TO THE END OF THE TAF
CYCLE WHERE WE COULD SEE 15 KT SUSTAINED WINDS GUSTS UP TO 20-25 KT
THROUGH THE EARLY EVENING. MODERATE TO HIGH CONFIDENCE IN THE
FORECAST.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR CONDITIONS AND ONSHORE WINDS ARE
FORECAST FOR THIS AFTERNOON. TONIGHT, THE SIGNAL FOR SOME WEAK
OFFSHORE OR SOUTHERLY FLOW BEFORE BECOMING MORE LIGHT AND VARIABLE
TOMORROW MORNING. MODELS ALSO SHOW THE POTENTIAL FOR SOME MVFR
CIGS AROUND THE REGION BUT NOT FULLY SOCKING US IN. OPTED TO KEEP
THE SCT MENTION OF MVFR CIGS AND WAIT TO SEE HOW THE MODELS TREND.
IT COULD BE HAVE A FEW HOURS OF BKN TO OVC MVFR CIGS OVERNIGHT,
WITH SKIES MIXING OUT BY MID TO LATE MORNING. MODERATE CONFIDENCE
IN THE FORECAST.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 939 AM PDT SUN OCT 25 2026
GENTLE NORTH TO NORTHWEST BREEZES GRADUALLY BECOME MODERATE TO
FRESH EARLY THIS WEEK. STRONG GUSTS INCREASE ACROSS THE SOUTHERN
COASTAL WATERS NEAR POINT SUR AND MONTEREY BAY BY MONDAY
AFTERNOON, WITH SOME ISOLATED NEAR GALE FORCE GUSTS POSSIBLE.
MODERATE SEAS OF 4 TO 5 FT ARE EXPECTED TODAY FOR THE OFFSHORE
WATERS, BUT WILL BUILD TO 6 TO 8 FT SEAS MONDAY INTO TUESDAY.
SLIGHT SEAS OF 2 TO 3 FT HOLD TODAY AT THE IMMEDIATE COASTLINE AND
BUILD TO MODERATE 4 TO 6 FT FOR MONDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...COASTAL FLOOD ADVISORY UNTIL 3 PM PDT THURSDAY FOR CAZ006-506-
508-529-530.
COASTAL FLOOD ADVISORY FROM 9 AM MONDAY TO 3 PM PDT THURSDAY FOR
CAZ505-509.
PZ...SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT MONDAY FOR MRY BAY.
SMALL CRAFT ADVISORY FROM 3 PM MONDAY TO 3 AM PDT TUESDAY FOR
PIGEON PT TO PT PINOS 0-10 NM-PT PINOS TO PT PIEDRAS
BLANCAS 0-10 NM.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...KR
MARINE...KR
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