808
FXUS66 KMTR 261812
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1112 AM PDT SAT SEP 26 2026
..NEW AVIATION AND MARINE
KEY MESSAGES
UPDATED AT 1238 PM PDT FRI SEP 25 2026
- COOLER CONDITIONS THROUGH THE WEEKEND
- WARMER TEMPERATURES NEXT WEEK
SHORT TERM
ISSUED AT 1154 PM PDT FRI SEP 25 2026
(TONIGHT THROUGH SUNDAY)
COOLER AIR CONTINUES TO MOVE IN ON NORTHWEST WINDS; THE ACV-SFO
PRESSURE GRADIENT IS 3.4 MB AND SFO-SAC IS 1.9 MB. COOLER AIR IS
COMBINING WITH NOCTURNAL RADIATIVE COOLING AND UPSLOPING WINDS
FORMING PATCHY LOW CLOUDS AND MIST. RADIATIVE COOLING WILL ALSO
HELP RESULT IN PATCHY VALLEY FOG FORMING OVERNIGHT AND SATURDAY
MORNING.
ON AVERAGE OUR SEP WEATHER PATTERN HAS BEEN INFLUENCED BY LARGE
SCALE TROUGHING, WITH MANY AREAS AWAY FROM THE COASTLINE BENEFITING
FROM BELOW SEP NORMALS FOR THE MONTH TO DATE. IF YOU'RE ENJOYING
THE WEATHER, IT'S A NICE WEEKEND SHAPING UP WITH SATURDAY DAYTIME
HIGHS IN THE 60S/70 AT THE COAST, MOSTLY 70S INLAND EXCEPT IN THE
80S ACROSS THE SOUTHERN INTERIOR OF MONTEREY AND SAN BENITO
COUNTIES. ALSO FOR SUNDAY DAYTIME HIGHS WILL BE BELOW LATE SEP
NORMALS WITH HIGHS MAINLY IN THE 60S AND 70S, QUITE NICE, IT COULD
BE WARMER/HOTTER THIS TIME OF YEAR.
LONG TERM
ISSUED AT 1154 PM PDT FRI SEP 25 2026
(SUNDAY NIGHT THROUGH NEXT FRIDAY)
COOL TEMPERATURES CARRYOVER INTO MONDAY, THEN WARMING RETURNS
TUESDAY THROUGH LATE WEEK WITH INCREASING 500 MB RIDGING. DRY
WEATHER IS FORECAST DURING THIS TIMEFRAME. DAYTIME HIGHS TUESDAY
THROUGH LATE WEEK WILL WARM BACK TO THE 80S TO LOWER 90S INLAND
WHILE IT'LL BE COOLER NEARER THE COAST WITH HIGHS GENERALLY IN
THE UPPER 60S AND 70S.
AVIATION
(18Z TAFS)
ISSUED AT 1046 AM PDT SAT SEP 26 2026
STRATUS IS CLEARING RAPIDLY ACROSS AFFECTED AREA TERMINAL AT THIS
HOUR. VFR CONDITIONS EXPECTED PREVAIL THROUGH THIS AFTERNOON WITH
A RETURN OF LOW CLOUDS EXPECTED THIS EVENING OVER COASTAL
TERMINALS (KMRY AND KHAF) AND AFTER MIDNIGHT/EARLY SUNDAY MORNING
OVER INLAND TERMINALS.
A SHORT WAVE TROUGH APPROACHING THE REGION TONIGHT INTO SUNDAY
WILL DEEPENS THE MARINE LAYER OVERNIGHT. THIS MAY RESULT IN LIGHT
RAIN OR DRIZZLE ESPECIALLY ALONG THE COAST. HOWEVER THE
RELATIVELY DRY BOUNDARY LAYER MAY NOT ALLOW IT TO REACH THE GROUND
AND MAY RESULT IN VIRGA.
VICINITY OF SFO...VFR CONDITIONS WITH SCATTERED HIGH CLOUDS WILL
PREVAIL THROUGH THE REMAINDER OF THE DAY WITH MODERATE CONFIDENCE
THAT MVFR CIGS WILL RETURN OVERNIGHT. LIGHTER WINDS THAN YESTERDAY
ARE ANTICIPATED. AN APPROACHING SHORT WAVE TROUGH WILL DEEPENS
THE MARINE LAYER OVERNIGHT RESULTING IN THE POSSIBILITY OF WET
RUNWAYS BY MORNING DUE TO LIGHT RAIN OR DRIZZLE.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH THE
REMAINDER OF THE DAY WITH MODERATELY HIGH CONFIDENCE THAT MVFR
CIGS WILL RETURN THIS EVENING. LIGHT TO LOCALLY MODERATE ONSHORE
FLOW IS ANTICIPATED. AN APPROACHING SHORT WAVE TROUGH WILL
DEEPENS THE MARINE LAYER OVERNIGHT RESULTING IN THE POSSIBILITY
OF WET RUNWAYS BY MORNING DUE TO LIGHT RAIN OR DRIZZLE.
MARINE
(TODAY THROUGH THURSDAY)
ISSUED AT 907 AM PDT SAT SEP 26 2026
MODERATE NORTH WINDS WILL PERSIST THROUGH THE REMAINDER OF THE
WEEKEND INCREASING SUNDAY NIGHT INTO MONDAY BECOMING STRONG AND
GUSTY AS A RIDGE OF HIGH PRESSURE BEGINS BUILDING IN OVER THE
EPAC TIGHTENING THE PRESSURE GRADIENT ACROSS THE COASTAL WATERS.
STRONGEST WINDS WILL BE OVER THE OUTER COASTAL WATERS ACCOMPANIES
BY HAZARDOUS BOATING CONDITIONS.
FIRE WEATHER
ISSUED AT 420 AM PDT SAT SEP 26 2026
OUR DIFFUSE COLD FRONT CONTINUES TO SLOWLY MOVE SOUTHWARD THROUGH
SOUTHERN CALIFORNIA. IN ITS WAKE, SOME AREAS HAVE BENEFITED FROM
THE COOLER AND SLIGHTLY MORE "MOIST" CONDITIONS THIS MORNING. THE
EXCEPTION, HOWEVER, IS ACROSS THE HIGHER TERRAIN OF THE SANTA
CRUZ MOUNTAINS AS WELL AS THE SANTA LUCIA AND DIABLO RANGES WHERE
RH RECOVERY REMAINS POOR (20-40%). AFTERNOON HUMIDITY WILL REMAIN
UNDER 40%, LARGELY FOR AREAS AWAY FROM THE COAST. A PUSH OF
ONSHORE FLOW IS EXPECTED LATER THIS EVENING INTO SUNDAY MORNING
RESULTING IN THE MARINE LAYER DEEPENING TO AROUND 2,000 FEET AHEAD
OF AN UPPER TROUGH. THIS MOISTURE PUSH SHOULD DIMINISH THE AREAL
COVERAGE OF POOR RH RECOVERY SUNDAY AND MONDAY MORNING. A FEW
SPRINKLES CANNOT BE RULED OUT ALONG THE HIGHEST PEAKS ASSOCIATED
WITH THIS UPPER LOW SUNDAY AM. DRY AND MODEST OFFSHORE BREEZES
WILL BE A POSSIBILITY TUESDAY AND INTO WEDNESDAY, WITH THE
POTENTIAL FOR WIND GUSTS ABOVE 35 MPH BEING GREATEST ACROSS THE
HIGHER TERRAIN OF THE NORTH BAY IN THE WAKE OF THIS UPPER LOW.
FARTHER SOUTH ACROSS THE CENTRAL COAST, THE PRIMARY IMPACT FROM
THIS LOW WILL BE A RETURN TO WIDESPREAD POOR RH RECOVERY WITH SOME
LOCALES ACROSS THE SANTA LUCIA RANGE STRUGGLING TO SEE MAX RH
ABOVE 30% WEDNESDAY MORNING.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT MONDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT MONDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PIGEON PT
TO PT PINOS 10-60 NM.
SHORT TERM...CANEPA
LONG TERM....CANEPA
AVIATION...CW
MARINE...CW
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