677
FXUS66 KMTR 230201
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
701 PM PDT FRI MAY 22 2026
..NEW UPDATE
KEY MESSAGES
UPDATED AT 1250 PM PDT FRI MAY 22 2026
- DIURNALLY DRIVEN ONSHORE WINDS DURING THE AFTERNOON AND EARLY
EVENING THROUGH EARLY NEXT WEEK
- GRADUAL COOLING TREND CONTINUES WITH SEASONAL TEMPERATURES FOR
THE UPCOMING WEEKEND AND COOLER TEMPERATURES EARLY NEXT WEEK
UPDATE
ISSUED AT 658 PM PDT FRI MAY 22 2026
COASTAL STRATUS IS BEGINNING TO FLOW INTO THE INLAND REGIONS THIS
EVENING, PARTICULARLY THROUGH THE PETALUMA GAP, GOLDEN GATE, AND
ACROSS THE MONTEREY BAY REGION. THE LATEST READINGS FROM THE
BODEGA BAY PROFILER SUGGEST THAT THE MARINE LAYER HAS FURTHER
THICKENED TO AROUND 2000 FEET. IF THIS HOLDS OVERNIGHT, THE HIGHER
ELEVATIONS AND PERHAPS THE VERY EASTERN SECTIONS OF CONTRA COSTA
COUNTY WILL BE THE ONLY REGIONS TO ESCAPE STRATUS COVER TONIGHT.
DIALH
SHORT TERM
ISSUED AT 1250 PM PDT FRI MAY 22 2026
(THIS EVENING THROUGH SATURDAY)
THE MARINE LAYER DEEPEN TO ~1500 FT THIS MORNING AND RESULTED IN
COOLER CONDITIONS ALONG THE COAST AND ADJACENT VALLEYS. MAY NOT HAVE
LOWERED TEMPERATURE IN THESE AREAS ENOUGH, HOWEVER THEY ARE ON A
WARMING TREND NOW THE SUN IS OUT. THUS, EXPECTING AFTERNOON
TEMPERATURES TO WARM INTO THE UPPER 70S TO MIDDLE 80S ACROSS THE
INTERIOR, LOWER 60S TO LOWER 70S AROUND THE SAN FRANCISCO BAYSHORE,
AND UPPER 50S TO MIDDLE 60S NEAR THE COAST. DRY CONDITIONS PERSIST
THIS AFTERNOON WITH ELEVATIONS ABOVE 1500 FT ARE SEEING 10%-30%
HUMIDITY VALUES.
AS THE MARINE LAYER IS FORECAST TO REMAIN STEADY, LOW CLOUDS NEAR
THE COAST WILL SPREAD FURTHER INLAND THIS EVENING AND SPREAD DEEPER
INTO THE VALLEYS EARLY SATURDAY MORNING. THERE IS ALSO THE POTENTIAL
FOR COASTAL DRIZZLE, YET THE PROBABILITY IS NOT GREAT ENOUGH TO
INCLUDE IN THE OFFICIAL FORECAST GRIDS.
FOR SATURDAY AFTERNOON, WE ARE EXPECTING SLIGHTLY COOLER
TEMPERATURES THAN TODAY AS STRATUS WILL BE SLOWER TO CLEAR. THIS IS
ALSO IN RESPONSE TO MORE ZONAL FOR DEVELOPING OVER THE REGION.
LONG TERM
ISSUED AT 1250 PM PDT FRI MAY 22 2026
(SATURDAY NIGHT THROUGH NEXT THURSDAY)
ZONAL FLOW WILL PERSIST ON SUNDAY, THUS TEMPERATURES WILL BE SIMILAR
TO THOSE ON SATURDAY AS FAR AS AFTERNOON MAXIMUM TEMPERATURES GO.
DURING THE LATE EVENING AND OVERNIGHT HOURS, CANNOT RULE OUT COASTAL
DRIZZLE AGAIN SATURDAY NIGHT INTO SUNDAY MORNING.
BY LATE MONDAY AND EARLY TUESDAY, A COLD FRONT ASSOCIATED WITH A
DEEP UPPER LEVEL THROUGH IS FORECAST TO SWEEP ACROSS THE REGION.
THIS WOULD RESULT IN DRIZZLE AND/OR LIGHT RAIN AS THE FRONT MOVES
FROM NORTH TO SOUTH ACROSS THE BAY AREA AND CENTRAL COAST. HOWEVER,
WIDESPREAD RAINFALL IS NOT EXPECTED AND WILL BE VERY LIGHT NOT
AMOUNTING TO MUCH MORE THAN A FEW HUNDREDTHS OF AN INCH. IN WAKE OF
THE FRONTAL PASSAGE, THE MARINE LAYER MAY MIX OUT AND ALLOW FOR
COASTAL LOCATIONS SLIGHTLY WARMER COMPARED TO THIS WEEKEND. WINDS
ARE ALSO FORECAST TO STRENGTHEN OVER THE COASTAL WATERS ON TUESDAY
AND WEDNESDAY.
FROM THE PREVIOUS FORECASTER: "TOWARDS THE LATER PART OF THE WEEK,
THE ENSEMBLE MODEL RUNS BEGIN TO DIVERGE AS THE EVOLUTION OF THE
UPPER LEVEL LOW AND INCOMING RIDGING BECOMES UNCERTAIN. MOST RUNS
LEAN TOWARDS A WARMING TREND FOR THAT PERIOD, WHICH IS REFLECTED IN
THE CURRENT FORECAST, WITH A SIGNIFICANT MINORITY (AROUND 30-40% OF
THE RUNS) SUGGESTING THAT SOME FORM OF TROUGH LINGERS THROUGH THE
PERIOD."
AVIATION
(00Z TAFS)
ISSUED AT 533 PM PDT FRI MAY 22 2026
A PROMINENT COASTAL STRATUS DECK IS EXPECTED TO IMPACT MOST
TERMINALS FRIDAY NIGHT INTO THE OVERNIGHT HOURS AS THE MARINE LAYER
DEEPENS TO ~1800 FEET BY EARLY SATURDAY MORNING. THE STRATUS PUSH
ONSHORE WILL BRING IFR-LIFR CEILINGS TO ALL TERMINALS EXCEPT FOR THE
INTERIOR SOUTH AND EAST BAY VALLEYS. VISIBILITY IMPACTS WILL BE
LIMITED TO THE COASTAL AND NORTH BAY SITES COINCIDING WITH THE LOWER
CEILINGS. CONDITIONS ARE EXPECTED TO IMPROVE TO VFR BY SATURDAY
AFTERNOON WITH COASTAL SITES EXPERIENCING SOME LINGERING LOW-LEVEL
STRATUS. GENTLE TO MODERATE BREEZES WILL PREVAIL THROUGH THE TAF
PERIOD.
VICINITY OF SFO...MODERATE WINDS PREVAIL THROUGH THE EVENING BEFORE
EASING UP LATE FRIDAY NIGHT. AS THE WINDS BECOME LIGHT, THE STRATUS
DECK WILL BEGIN TO CREEP IN WITH BORDERLINE MVFR-IFR CEILINGS. THE
STRATUS DECK IS EXPECTED TO REMAIN UNTIL IT SCATTERS OUT BY LATE
MORNING SATURDAY WHEN WINDS INCREASE TO MODERATE STRENGTH.
CONDITIONS WILL REMAIN VFR THROUGH THE END OF TAF PERIOD, THOUGH
THERE MAY BE ANOTHER RETURN OF LOW CEILINGS SATURDAY NIGHT.
SFO BRIDGE APPROACH...THE MARINE LAYER WILL NOT BE AS PROMINENT OR
DEEP. THEREFORE, ANY DEVELOPING LOW CLOUD DECK WILL LIKELY REMAIN
FEW TO SCATTERED BEFORE DISSIPATING BY LATE SATURDAY MORNING. WINDS
FOLLOW THE SAME GENERAL PATTERN AS SFO, THOUGH REMAIN MORE NW TO W.
MONTEREY BAY TERMINALS...THE MARINE LAYER IS BEGINNING TO FUNNEL
INTO SALINAS VALLEY AS OF 5:30PM PDT FRIDAY. THE MARINE STRATUS WILL
CONTINUE TO PUSH INLAND BRINGING IFR CEILINGS AND MISTY CONDITIONS
TO THE TERMINALS BY FRIDAY EVENING. BY LATE FRIDAY NIGHT, IFR
CEILINGS WILL DEVELOP AS LOCAL LIGHT BREEZES DEVELOP. STRATUS SHOULD
BEGIN TO MIX OUT OF THE TERMINALS, RESULTING IN VFR CONDITIONS, BY
LATE SATURDAY MORNING AS ONSHORE WINDS INCREASE.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 838 AM PDT FRI MAY 22 2026
LIGHT TO MODERATE WINDS WILL SHIFT ACROSS THE WATERS THROUGH THE
DAY, BECOMING SOUTHWESTERLY AND LIGHT. THE SEA STATE WILL IMPROVE
HEADING INTO THE HOLIDAY WEEKEND AS NORTHWESTERLY SWELL CONTINUES
TO DECREASE.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM PDT SATURDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...RGASS
LONG TERM....RGASS
AVIATION...NAVARRETE
MARINE...MURDOCK
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