119
FXUS66 KMTR 141057
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
357 AM PDT THU AUG 14 2025
..NEW AVIATION, MARINE
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.
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
(12Z TAFS)
ISSUED AT 356 AM PDT THU AUG 14 2025
CURRENTLY A MIXED BAG OF LIFR-MVFR AT THE TERMINALS WITH A MARINE
LAYER OF 1,400 FEET. ASIDE FROM HAF AND MRY, HIGH CONFIDENCE IN VFR
PREVAILING THROUGH THE AFTERNOON WITH LESS THAN A 40% CHANCE FOR SUB-
VFR CEILINGS TO RETURN TO BAYSHORE AND INLAND TERMINALS WITH A 70%
CHANCE FOR CEILINGS ON THE CUSP OF LIFR/IFR TO RETURN TO COASTAL
TERMINALS TONIGHT. THE REASON FOR THIS IS SURFACE HIGH PRESSURE
BUILDING INTO NORTHERN CALIFORNIA (COMPRESSING THE MARINE LAYER)
WILL SUPPORT A NORTHERLY (DRYING) COMPONENT - THUS, ENTRAINING DRY
AIR INTO THE MARINE LAYER.
VICINITY OF SFO...CURRENTLY IFR WITH WESTERLY FLOW. HIGH CONFIDENCE
IN VFR THROUGH THE AFTERNOON WITH ONLY A 40% CHANCE FOR SUB-VFR
CEILINGS TO RETURN TO THE TERMINAL TONIGHT. WESTERLY WINDS WILL
PREVAIL THROUGH THE TAF PERIOD.
SFO BRIDGE APPROACH...HIGH CONFIDENCE IN THE APPROACH REMAINING VFR
THROUGH THE AFTERNOON WITH ONLY A 40% CHANCE FOR LOW STRATUS CLOUDS
TO IMPACT THE SAN MATEO BRIDGE APPROACH AT ALL AFTER THIS MORNING,
AND THAT WOULD BE ONLY ON THE FAR NORTHERN SIDE OF IT.
MONTEREY BAY TERMINALS...CURRENTLY IFR WITH SOUTHWESTERLY FLOW AT
MRY AND IFR WITH NORTHWESTERLY FLOW AT SNS. BRIEF VFR WILL BE
ACHIEVED AT SNS WITH MODERATE (30-50%) CONFIDENCE THAT MRY REMAINS
IN THE SUB-VFR CATEGORY. HIGH (70%) CONFIDENCE THAT CEILINGS ON THE
CUSP OF IFR/LIFR RETURN TO BOTH TERMINALS TONIGHT.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 356 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 FROM 9 AM THIS MORNING TO 3 PM PDT THIS
AFTERNOON FOR PT ARENA TO PT REYES 0-10 NM.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 3 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 3 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 3 AM PDT FRIDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT THIS AFTERNOON FOR PT ARENA
TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 9 PM PDT THIS
EVENING FOR PIGEON PT TO PT PINOS 10-60 NM.
GALE WARNING FROM 9 PM THIS EVENING TO 3 AM PDT FRIDAY FOR
PIGEON PT TO PT PINOS 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...SARMENT
MARINE...SARMENT
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