402
FXUS66 KMTR 290342
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
841 PM PDT FRI AUG 28 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1253 PM PDT FRI AUG 28 2026
- SLIGHT CHANCE OF RAIN SHOWERS THROUGH THIS AFTERNOON WITH
THUNDERSTORM CHANCES FOCUSED ON THE CENTRAL COAST, TAPERING OFF
BY THIS EVENING
- COOLING TREND CONTINUES INTO EARLY NEXT WEEK
SHORT TERM
ISSUED AT 1253 PM PDT FRI AUG 28 2026
(THIS EVENING THROUGH SATURDAY NIGHT)
TEMPERATURES ARE STRUGGLING TO WARM TO THEIR FORECASTED MAXIMUM
VALUES THIS AFTERNOON. THIS IS AS ABUNDANT MID-TO-HIGH LEVEL CLOUD
COVER FROM REMNANT MOISTURE FROM FORMER TROPICAL STORM ISELLE MOVES
OVER THE REGION. HOWEVER, WE ARE SEEING VIA SATELLITE THAT BREAKS IN
THIS CLOUD COVER ARE APPEARING OFF OF THE CENTRAL COAST. THIS MAY
RESULT IN ENOUGH HEATING TO DESTABILIZE CONDITIONS ACROSS THIS
REGION. AS SUCH, WE ARE KEEPING THE RED FLAG WARNING IN EFFECT
THROUGH 3 PM THIS AFTERNOON GIVEN THE DRY LIGHTNING POTENTIAL.
THE MID-TO-UPPER LEVEL MOISTURE IS FORECAST TO SHIFT EASTWARD INTO
THE SIERRA NEVADA AS THE TROUGH OFF OF THE PACIFIC NORTHWEST COAST
DEEPENS. THUS, RAIN SHOWERS AND THE POTENTIAL FOR THUNDERSTORMS
GREATLY DIMINISHES AFTER SUNSET. HOWEVER, THE AFOREMENTIONED TROUGH
WILL RESULT IN A DEEPENING OF THE MARINE LAYER TONIGHT AND INTO THE
UPCOMING WEEKEND. THEREFORE, AN INCREASED PROBABILITY OF STRATUS NEAR
THE COAST AND INTO THE ADJACENT VALLEYS OVERNIGHT TONIGHT.
SLIGHTLY WARMER TEMPERATURES ARE EXPECTED ON SATURDAY AS LOW CLOUDS
THAT DO DEVELOP OVERNIGHT RETREAT BACK TO THE COASTLINE BY TOMORROW
AFTERNOON AND GIVE WAY TO MOSTLY SUNNY SKIES ACROSS THE INTERIOR.
LONG TERM
ISSUED AT 1253 PM PDT FRI AUG 28 2026
(SUNDAY THROUGH NEXT THURSDAY)
A REINFORCING TROUGH DEEPENS OFF OF THE PACIFIC NORTHWEST COAST BY
MONDAY, ALLOWING AFTERNOON TEMPERATURES TO BE SOME 5 TO 15 DEGREES
BELOW SEASONAL AVERAGES. BEYOND MONDAY AND TUESDAY, THE LATEST
GUIDANCE INDICATES TROUGHING OFF OF THE WEST COAST WILL BE STRONGER
THAN PREVIOUS ANTICIPATED. THEREFORE, LESS LIKELY TO SEE TROPICAL
MOISTURE FROM THE EASTERN PACIFIC TO ADVECT NORTHWARD. HOWEVER,
CONFIDENCE REMAINS LOW AT THIS TIME. BE SURE TO KEEP UP TO DATE WITH
THE LATEST FORECAST INFORMATION FROM A TRUSTED AND RELIABLE
SOURCE.
AVIATION
(06Z TAFS)
ISSUED AT 841 PM PDT FRI AUG 28 2026
IT'S VFR EXCEPT FOR AREAS OF STRATUS /MVFR-IFR/ ALONG THE
IMMEDIATE COASTLINE. THE MID-LATITUDE WIND FLOW PATTERN IS
RETURNING WITH DRYING AIR TONIGHT AND SATURDAY. THE GFS SHOWS
PRECIPITABLE WATER QUICKLY LOWERING TONIGHT AND SATURDAY, NEAR THE
10TH PERCENTILE ON OAKLAND UPPER AIR SOUNDINGS FOR LATE AUGUST. WITH
DECREASING WATER VAPOR ALOFT THIS WILL RESULT IN RADIATIVE COOLING
AND WITH LINGERING BOUNDARY LAYER MOISTURE IT'S LIKELY TO CONTINUE
COOLING TO SATURATION RESULTING IN ADDITIONAL FOG AND STRATUS
/IFR-LIFR/. DIURNAL SURFACE WARMING WILL MIX OUT FOG AND STRATUS
IMPROVING CONDITIONS TO MVFR-VFR BY LATE SATURDAY MORNING AND
AFTERNOON. STRATUS AND FOG /MVFR-IFR/ REDEVELOP SATURDAY NIGHT.
VICINITY OF SFO...VFR UNTIL TEMPO STRATUS /MVFR/ 06Z-08Z TONIGHT,
THEN STRATUS /MVFR/ PREVAILING TONIGHT TO 18Z SATURDAY MORNING.
THEREAFTER VFR IS FORECAST SATURDAY AFTERNOON TO MID EVENING. WEST
WIND NEAR 15 KNOTS TONIGHT DECREASING TO 8 TO 10 KNOTS LATE TONIGHT
AND SATURDAY MORNING. WEST WIND INCREASING TO 15 TO 25 KNOTS
SATURDAY AFTERNOON AND EVENING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR THEN STRATUS /IFR-LIFR/ REDEVELOPS
TONIGHT AND SATURDAY MORNING. SURFACE WARMING WILL MIX OUT STRATUS
BY LATE SATURDAY MORNING AND AFTERNOON. STRATUS /IFR/ REDEVELOPS
SATURDAY NIGHT. WEST TO NORTHWEST WINDS 5 TO 15 KNOTS.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 834 PM PDT FRI AUG 28 2026
FRESH NORTHWEST BREEZES WITH OCCASIONAL NEAR GALE FORCE GUSTS
CONTINUE THROUGH THE WEEKEND AS WELL AS A LONG PERIOD SOUTHERLY
SWELL. THE LONG PERIOD SOUTHERLY SWELL PEAKS ON SATURDAY AROUND 17
TO 18 SECONDS AND GRADUALLY DIMINISHES BY SUNDAY NIGHT. WIND
DRIVEN SEAS BRIEFLY BUILD TO ROUGH SATURDAY AFTERNOON INTO SUNDAY
AND GRADUALLY SUBSIDE TO MODERATE THROUGH NEXT WEEK.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 9 AM SATURDAY TO 3 AM PDT SUNDAY FOR
MRY BAY.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT SUNDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT ARENA TO PT REYES 0-10 NM-PT ARENA TO PT
REYES 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SUNDAY FOR PIGEON PT TO PT
PINOS 0-10 NM.
SHORT TERM...RGASS
LONG TERM....RGASS
AVIATION...CANEPA
MARINE...CANEPA
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, X, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
X.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page