144
FXUS66 KMTR 141751
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1051 AM PDT THU AUG 14 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1222 AM PDT THU AUG 14 2025
- A DEEP MARINE LAYER WILL BRING COASTAL DRIZZLE THIS MORNING.
- TEMPERATURES WILL WARM SLIGHTLY THROUGH FRIDAY BEFORE RETURNING
BACK BELOW NORMAL THIS WEEKEND.
- STRONG NW WINDS WILL ARRIVE TO THE COAST TODAY AND SPREAD
INLAND FRIDAY - SATURDAY.
UPDATE
ISSUED AT 927 AM PDT THU AUG 14 2025
MARINE LAYER IS WHERE IT'S AT THIS MORNING. SOLID MARINE LAYER
WITH EXCELLENT INLAND PUSH TO KICK OFF THE DAY. LOW LEVEL FORCING
AND TOPOGRAPHIC ENHANCEMENT HAD LED TO AMPLE DRIZZLE THIS
MORNING. SAMPLING OF AUTOMATED SENSORS AROUND THE REGION SHOWS A
FEW BUCKET TIPS HAVE OCCURRED OVER THE LAST SIX HOURS, APPROX
.01-0.03 INCHES. IT'S GOING TO BE A SLOW PROCESS, BUT GRADUAL
THINNING AND ROLLING BACK OF THE MARINE LAYER BACK TO THE COAST
WILL OCCUR THROUGH LATE MORNING. CURRENT FORECAST CAPTURES NEAR
TERM SENSIBLE WEATHER. NO UPDATE NEEDED AT THIS TIME.
SHORT TERM
ISSUED AT 1222 AM PDT THU AUG 14 2025
(TODAY AND TONIGHT)
DUE TO A 500MB TROUGH JUST OFFSHORE, A DEEP MARINE LAYER IS
BRINGING EXTENSIVE STRATUS COVERAGE TO THE BAY AREA AND CENTRAL
COAST TONIGHT. THE FT. ORD PROFILER IS RECORDING THE MARINE LAYER
DEPTH AT OVER 2,000 FEET AND AIRPORTS ARE REPORTING CEILINGS AS
LOW AS 500 FEET. THAT MEANS THE CLOUD LAYER DEPTH IS AROUND 1,500
FEET, WHICH IS MORE THAN ENOUGH TO BRING DRIZZLE TO THE USUAL
COASTAL AND TERRAIN ENHANCED AREAS THIS MORNING. THE CLOUDS WILL
EVENTUALLY CLEAR FOR MOST BY MID-DAY, BUT WITH STRONG NW WINDS,
THE SF PENINSULA AND SOUTHERN MONTEREY BAY MAY BE STUCK IN THE
CLOUDS ALL DAY.
THE EUREKA-SFO GRADIENT HAS REACHED 2.1 MB AS OF 07Z, AND SHOULD
CONTINUE TO STRENGTHEN TO 5 OR 6 MB THROUGH THE DAY AS SURFACE
HIGH PRESSURE BUILDS OVER NORTHERN CALIFORNIA. THE PGE-WRF
ENSEMBLE MEAN PEAKS AT 6.1 MB JUST AFTER MIDNIGHT. THIS N-S
GRADIENT, COMBINED WITH THE TYPICAL DIURNALLY DRIVEN W-E GRADIENT,
WILL BRING STRONG NW WINDS THIS EVENING WITH GUSTS REACHING UP TO
25 MPH ALONG THE COAST AND IN N-S ORIENTED VALLEYS.
LONG TERM
ISSUED AT 1222 AM PDT THU AUG 14 2025
(FRIDAY THROUGH WEDNESDAY)
THE HIGH PRESSURE OVER N. CALIFORNIA WILL PERSIST THROUGH THE DAY
FRIDAY, MAINTAINING THE STRONG NW WINDS FROM THURSDAY. THE HIGH
PRESSURE AND STRONG WINDS ABOVE THE BOUNDARY LAYER WILL BOTH
COMPRESS THE MARINE LAYER AND MIX IN SOME DRY AIR. THIS WILL LEAD
TO LESS CLOUD COVERAGE FRIDAY MORNING. AS A RESULT THE
TEMPERATURES WILL BE A FEW DEGREES WARMER BY THE AFTERNOON,
APPROACHING SEASONAL NORMALS. IT MAY NOT FEEL AS WARM WITH THE
STRONG WINDS THROUGHOUT THE DAY. THE N-S GRADIENT WILL GRADUALLY
DECREASE OVER THE WEEKEND ALLOWING THE WINDS TO ABATE AND
TEMPERATURES TO RETURN BACK BELOW NORMAL. THROUGH THE WORK WEEK
THE OVERALL TROUGHING PATTERN WILL REMAIN, ALTHOUGH THERE IS SOME
INDICATION THAT THE 4-CORNERS HIGH WILL START TO PUSH WEST,
BRINGING A SLIGHT WARMING TREND THROUGH THE WORK-WEEK.
AVIATION
(18Z TAFS)
ISSUED AT 1050 AM PDT THU AUG 14 2025
CONDITIONS ARE RETURNING TO VFR LATE THIS MORNING, WITH THE
EXCEPTION OF MRY AND HAF WHERE IFR/MVFR CONDITIONS MAY PERSIST
THROUGH THE REMAINDER OF THE DAY. HOWEVER, THEIR IS LOW TO MODERATE
CONFIDENCE FOR CONDITIONS AT BOTH SITES TO SCATTER OUT BRIEFLY THIS
AFTERNOON. HIGH CONFIDENCE FOR ONSHORE WINDS TO INCREASE THIS
AFTERNOON BEFORE EASING AFTER SUNSET AROUND THE MONTEREY BAY
TERMINALS AND EARLY FRIDAY MORNING AROUND THE BAY AREA TERMINALS.
HIGH CONFIDENCE FOR IFR/MVFR CEILINGS TO MAKE AN EARLY RETURN TO THE
MONTEREY BAY TERMINALS THIS EVENING. HOWEVER, CONFIDENCE REMAINS LOW
FOR THE BAY AREA TERMINALS TO RECEIVE SUB-VFR CONDITIONS EARLY FRIDAY
MORNING.
VICINITY OF SFO...VFR. ONSHORE WINDS WILL INCREASE THIS AFTERNOON
WITH GUSTS UP TO 25KT AT SFO. LOW CONFIDENCE FOR CEILINGS TO RETURN
AROUND THE BAY AREA TERMINALS EARLY FRIDAY MORNING. ONLY HAVE OAK
WITH A TEMPO FOR A FEW HOURS WITH NO CEILINGS AT SFO FRIDAY MORNING.
ONCE ANY LOW CLOUDS THAT DO DEVELOP SCATTER OUT AND/OR CLEAR,
ONSHORE WINDS WILL ONCE AGAIN INCREASE AND BECOME GUSTY BY FRIDAY
AFTERNOON. THERE IS HIGH CONFIDENCE FOR WIND SPEEDS TO BE STRONGER
THAN PREVIOUS DAYS.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR/MVFR. MODERATE TO HIGH CONFIDENCE
FOR MRY TO REMAIN MVFR THROUGHOUT MUCH OF THE TAF PERIOD.
MEANWHILE, SNS SHOULD RETURN TO VFR CONDITIONS HERE WITHIN THE
NEXT FEW HOURS. ONSHORE WINDS WILL INCREASE THIS AFTERNOON BEFORE
EASING AFTER SUNSET. HIGH CONFIDENCE FOR IFR/MVFR (POTENTIALLY
LOWERING TO LIFR EARLY FRIDAY MORNING) TO RETURN THIS EVENING AND
PERSIST THROUGH THE REMAINDER OF THE TAF PERIOD.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 913 AM PDT THU AUG 14 2025
WIDESPREAD HAZARDOUS CONDITIONS WILL PERSIST THROUGH SATURDAY FOR
THE INNER WATERS AND OUTER WATERS DUE TO FRESH TO STRONG
NORTHWESTERLY BREEZES WITH GALE FORCE GUSTS, ESPECIALLY FOR THE
OUTER WATERS AND COASTAL JET REGIONS OF POINT REYES AND POINT SUR.
THE BAYS WILL EXPERIENCE HAZARDOUS CONDITIONS FRIDAY AND SATURDAY
DUE TO FRESH TO STRONG WESTERLY BREEZES WITH NEAR-GALE FORCE
GUSTS. BREEZES WILL SLOWLY DIMINISH BY LATE WEEKEND AND CONTINUE
THAT TREND INTO EARLY NEXT WEEK. MODERATE TO ROUGH SEAS WILL
PREVAIL THROUGH SATURDAY FOR THE INNER WATERS AND OUTER WATERS
WITH WIDESPREAD MODERATE SEAS BY SUNDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 PM PDT THIS AFTERNOON FOR PT ARENA
TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 9 AM PDT FRIDAY FOR PT
ARENA TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 AM PDT FRIDAY
FOR PT REYES TO PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT FRIDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PIGEON PT
TO PT PINOS 10-60 NM.
GALE WARNING FROM 9 PM THIS EVENING TO 9 AM PDT FRIDAY FOR
PIGEON PT TO PT PINOS 10-60 NM.
UPDATE...MM
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...RGASS
MARINE...RGASS
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