068
FXUS66 KMTR 201914
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1214 PM PDT THU AUG 20 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1147 PM PDT WED AUG 19 2026
- GRADUAL COOLING TREND TODAY INTO THE BEGINNING OF THE WEEKEND
- ELEVATIONS ABOVE ABOUT 1000 FEET WILL HAVE WARM TEMPERATURES
AND RH VALUES IN THE TEENS EARLY THIS MORNING INTO THE
AFTERNOON
SHORT TERM
ISSUED AT 1147 PM PDT WED AUG 19 2026
(TODAY AND TONIGHT)
WE'VE BEEN IN THE MIDDLE OF A SUBTLE BACK AND FORTH BETWEEN
TROUGHING OVER THE EPAC AND RIDGING OVER THE DESERT SOUTHWEST THE
PAST WEEK OR SO. THE NET RESULT HAS BEEN ONLY SMALL CHANGES IN OUR
DAY-TO-DAY AMBIENT WEATHER CONDITIONS. HOWEVER, THE INFLUENCE OF
TROUGHING NUDGING BACK TO THE EAST TOWARD OUR COASTLINE TODAY, WILL
RESULT IN THE BEGINNING OF GRADUAL COOLING, THAT WILL CONTINUE INTO
THE WEEKEND. IMPROVED LOWER BOUNDARY LAYER ONSHORE FLOW WILL HELP
BRING TEMPERATURES AROUND 5-10 DEGREES BELOW NORMAL AWAY FROM THE
COAST, WHILE STILL REMAINING ABOVE NORMAL IN SOUTHERN MONTEREY
COUNTY. THE DEPTH OF THE MARINE LAYER INFLUENCE WILL INCREASE AS
WELL TODAY HELPING TO FURTHER SUPPORT COOLER TEMPERATURES. THE MORE
MILD OVERNIGHTS WE'VE BEEN SEEING WILL MODERATE CLOSER TO NORMAL
TOO, LEADING TO STRATUS PUSHING FARTHER INLAND AFTER SUNSET INTO
EARLY FRIDAY MORNING.
LONG TERM
ISSUED AT 1147 PM PDT WED AUG 19 2026
(FRIDAY THROUGH WEDNESDAY)
THE GRADUAL COOLING TREND INTO THE BEGINNING OF THE WEEKEND LEVELS
OFF BY SUNDAY INTO THE BEGINNING OF NEXT WEEK WITH ONLY MINOR,
LIKELY UNNOTICEABLE CHANGES THROUGH THE REMAINDER OF THE EXTENDED
FORECAST. THE STRONG DOME OF HIGH PRESSURE OVER THE DESERT
SOUTHWEST SHOWS HINTS OF SHIFTING BACK TO THE WEST BY THE END OF
NEXT WEEK, WHICH WOULD BRING WARMER TEMPERATURES, HOWEVER THERE IS
STILL NO SIGNAL FOR A SIGNIFICANT PATTERN CHANGE. TROPICAL WAVE
ACTIVITY IS STILL EXPECTED TO STEER WELL SOUTH AND WEST OF OUR
AREA WITH LITTLE TO NO IMPACTS ON OUR FORECAST ATTM.
AVIATION
(18Z TAFS)
ISSUED AT 1211 PM PDT THU AUG 20 2026
STRATUS HAS RETREATED TO THE COASTLINE WITH MOST TERMINALS IN VFR
AND A PARADE OF HIGH CLOUDS CRUISING OVERHEAD. HAF IS THE EXCEPTION
AS THEY MAY HAVE A BRIEF SCATTERING PERIOD THIS AFTERNOON BEFORE
DEVELOPING IFR CEILINGS AGAIN. TYPICAL ONSHORE BREEZE PATTERN
PERSISTS THROUGH THE TAF PERIOD WITH AN INCREASE THIS AFTERNOON. THE
MARINE LAYER RETURNS THIS EVENING WITH A MIXTURE OF MVFR, IFR, AND
LIFR CEILINGS IMPACTING COASTAL SITES AS EARLY AS SUNSET AND INLAND
SITES AROUND MIDNIGHT. MEDIUM CONFIDENCE ON THE CEILING FORECASTS
FOR LVK AND SJC AS THE MARINE LAYER IS EXPECTED TO COMPRESS SLIGHTLY
OVERNIGHT WHICH MAY IMPACT CEILING HEIGHTS AS WELL AS COVERAGE.
VICINITY OF SFO...ONSHORE WINDS INCREASE THROUGH THE DAY WITH VFR
CONDITIONS PREVAILING DURING MOST OF THE AFTERNOON. BORDERLINE
MVFR-IFR CEILINGS ROLL IN AROUND SUNSET TONIGHT AND PERSIST UNTIL
LATE MORNING FRIDAY. WESTERLY WINDS DECREASE THROUGH THE
OVERNIGHT HOURS AND INCREASE AS STRATUS CLEARS TOMORROW MORNING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR THROUGH THE AFTERNOON WITH WEST TO
NORTHWEST WINDS INCREASING TO AROUND 10 KT. IFR CEILINGS IMPACT
BOTH SNS AND MRY AROUND SUNSET TIME AND DROP TO LIFR OVERNIGHT AS
THE MARINE LAYER COMPRESSES. THIS COMPRESSION WILL IMPACT
VISIBILITY DUE TO MIST/DRIZZLE. CONDITIONS WILL GRADUALLY IMPROVE
BY LATE FRIDAY MORNING. MEDIUM CONFIDENCE ON EXACT TIMING OF LIFR
CONDITIONS.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 430 AM PDT THU AUG 20 2026
A MODERATE TO FRESH NORTHWESTERLY BREEZE PREVAILS THROUGH FRIDAY.
HAZARDOUS CONDITIONS FOR SMALL CRAFT DUE TO OCCASIONAL STRONG
NORTHWEST GUSTS CONTINUE ACROSS THE OUTER WATERS AND COASTAL JET
REGIONS INTO FRIDAY. MODERATE SEAS CONTINUE ACROSS THE OUTER
WATERS WITH WAVE HEIGHTS INCREASING TO BETWEEN 7 TO 8 FEET BEFORE
DECREASING FRIDAY INTO THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PIGEON PT
TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT FRIDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...JM
LONG TERM....JM
AVIATION...NAVARRETE
MARINE...KENNEDY
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