836
FXUS66 KMTR 140815
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
115 AM PDT THU AUG 14 2025
..NEW SHORT TERM, LONG TERM
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
(06Z TAFS)
ISSUED AT 1001 PM PDT WED AUG 13 2025
BREEZY ONSHORE FLOW COUPLED WITH THE MARINE LAYER GRADUALLY
INCREASING THIS EVENING, HAS RESULTED IN LOW STRATUS PUSHING FARTHER
INLAND THAN AT THIS TIME TWENTY FOUR HOURS AGO. EXPECT MVFR/IFR
CEILINGS TO PERSIST THROUGH THE OVERNIGHT WITH OCCASIONAL DROPS TO
LIFR FOR THE NORTH BAY AND BAY AREA POSSIBLE, MORE CONFIDENT FOR
PERIODS OF LIFR AT THE MONTEREY BAY TERMINALS.
VICINITY OF SFO...EXPECT MVFR/IFR CEILINGS TO PERSIST THROUGH THE
OVERNIGHT UNTIL EARLY THURSDAY AFTERNOON WITH AN EXPANDING MARINE
LAYER AND BREEZY ONSHORE FLOW. THE WINDOW FOR VFR ON THURSDAY
AFTERNOON WILL LIKELY BE SMALLER THAN THE PREVIOUS COUPLE OF DAYS.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR WILL CONTINUE THROUGH THE OVERNIGHT,
WITH A PERIOD OF LIFR EXPECTED IN THE HOURS SURROUNDING SUNRISE
THURSDAY MORNING. LOW CONFIDENCE IN THE TIMING OF VFR THURSDAY
AFTERNOON IF THERE IS ANY. MVFR CEILINGS MAY PERSIST THROUGH THE
AFTERNOON AND, IF SO, UNTIL THE END OF THE TAF PERIOD.
MARINE
(TONIGHT THROUGH NEXT TUESDAY)
ISSUED AT 904 PM PDT WED AUG 13 2025
MODERATE NORTHWESTERLY BREEZES OVERNIGHT WILL INCREASE TO BECOME
STRONG ON THURSDAY. HAZARDOUS CONDITIONS WILL BE PRESENT THURSDAY
WITH GALE FORCE GUSTS ACROSS THE OUTER WATERS AND ALONG THE
COASTAL JET REGION OF POINT REYES AND NEAR-GALE FORCE GUSTS ACROSS
THE REST OF THE INNER WATERS. MODERATE SEAS WILL INCREASE ON
FRIDAY, BECOMING ROUGH ACROSS BOTH THE INNER AND OUTER WATERS
THROUGH FRIDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT EARLY THIS MORNING FOR SF
BAY N OF BAY BRIDGE.
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...JM
MARINE...JM
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