469
FXUS66 KMTR 221808
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1108 AM PDT TUE SEP 22 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1201 AM PDT TUE SEP 22 2026
- WARMING TREND BEGINS TODAY THROUGH THURSDAY
- COOLER CONDITIONS FRIDAY INTO THE WEEKEND
UPDATE
ISSUED AT 904 AM PDT TUE SEP 22 2026
THERE WAS COASTAL DRIZZLE REPORTED AT SEVERAL LOCATIONS THIS
MORNING, BUT NOTHING MORE THAN A FEW HUNDREDTHS OF AN INCH. STRATUS
PUSHED WELL INLAND INTO MOST INTERIOR VALLEYS EARLY THIS MORNING AND
IS FORECAST TO RETREAT TO THE IMMEDIATE COAST BY LATE MORNING/EARLY
AFTERNOON. THIS WILL GIVE WAY TO MOSTLY SUNNY CONDITIONS INLAND THIS
AFTERNOON WITH TEMPERATURES WARMING INTO THE 60S NEAR THE COAST,
UPPER 60S TO LOW 70S AROUND THE BAYSHORE, AND MID 70S TO MID 80S
ACROSS THE INTERIOR. COASTAL AREAS WILL BE SOME 5-10 DEGREES BELOW
SEASONAL AVERAGES WITH THE INTERIOR HOLDING NEAR AVERAGE. A WARMING
TREND REMAINS ON TAP FOR WEDNESDAY AND THURSDAY, YET NO SIGNIFICANT
HEAT ANTICIPATED WITH THIS BRIEF WARMING TREND.
RGASS
SHORT TERM
ISSUED AT 1201 AM PDT TUE SEP 22 2026
(TODAY AND TONIGHT)
EXTENSIVE STRATUS HAS FLOWED INTO THE NORTH BAY VALLEYS, MONTEREY
BAY REGION, SALINAS VALLEY, HOLLISTER AREA, AND THE EAST BAY WEST OF
THE BERKELEY HILLS. ACROSS THE REST OF THE SF BAY AREA, PATCHES OF
STRATUS HAVE DEVELOPED NEAR LIVERMORE AND NORTH OF SAN JOSE, WITH
FURTHER EXPANSION EXPECTED THROUGH THE PRE-DAWN HOURS. THE CLOUD
DECK RETREATS BACK TO THE IMMEDIATE COAST LATE THIS MORNING INTO THE
EARLY AFTERNOON, BUT BY THE TIME IT DEVELOPS AGAIN TONIGHT, THE
MARINE LAYER WILL BE COMPRESSED, LEADING TO UNCERTAINTY OVER JUST
HOW FAR INLAND THE CLOUDS WILL GO.
THE CUT-OFF LOW THAT GAVE US THE LAST COUPLE DAYS OF COOLER
TEMPERATURES IS MOVING ACROSS THE STATE WITH THE CENTER CRAWLING
THROUGH THE MOJAVE DESERT INTO THE GREAT BASIN. THIS ALLOWS FOR MORE
ZONAL FLOW TO COME INTO THE STATE AND A WARMING TREND TO BEGIN
TODAY, WITH HIGH TEMPERATURES IN THE UPPER 70S TO THE MIDDLE 80S
ACROSS THE INLAND VALLEYS, INTO THE UPPER 80S IN THE FAR INTERIOR
REGIONS OF THE NORTH BAY AND SOUTHERN MONTEREY COUNTY, THE MIDDLE
60S TO THE MIDDLE 70S CLOSE TO THE BAYS, AND THE LOWER TO MIDDLE 60S
ALONG THE IMMEDIATE COAST. A BREEZY ONSHORE WIND WILL DEVELOP IN THE
AFTERNOON AND EVENING HOURS, WITH THE STRONGEST GUSTS OF 20 TO 30
MILES PER HOUR ALONG THE COAST, THROUGH FAVORED GAPS AND PASSES, AND
WITHIN THE NORTHERN SALINAS VALLEY.
AS A QUICK SIDE NOTE, TODAY WILL MARK THE AUTUMNAL EQUINOX AND THE
START OF ASTRONOMICAL FALL. AT 505 PM PACIFIC TIME, THE SUN'S
APPARENT PATH ON THE EARTH CROSSES THE EQUATOR, GIVING US 12 HOURS
EACH OF SUNLIGHT AND NIGHTTIME.
LONG TERM
ISSUED AT 1201 AM PDT TUE SEP 22 2026
(WEDNESDAY THROUGH MONDAY)
SLIGHT RIDGING WILL DEVELOP OVER CALIFORNIA OVER THE NEXT COUPLE OF
DAYS, AND WHILE THE RIDGE AXIS QUICKLY MOVES INTO THE INTERMOUNTAIN
WEST, THE RIDGE INFLUENCE WILL ALLOW FOR FURTHER WARMING WEDNESDAY
AND THURSDAY. HIGH TEMPERATURES WARM INTO THE MIDDLE 80S TO THE
MIDDLE 90S IN THE INLAND VALLEYS, THE MIDDLE 70S TO THE MIDDLE 80S
CLOSE TO THE BAYS, AND THE MIDDLE 60S TO THE LOWER 70S ALONG THE
PACIFIC COAST. POCKETS OF MODERATE HEATRISK ARE SCATTERED ACROSS THE
INTERIOR REGIONS, PARTICULARLY NEAR SAN JOSE, THE INTERIOR EAST BAY,
AND THE SANTA LUCIA RANGE. THESE POCKETS ARE NOT EXPANSIVE ENOUGH TO
MERIT A HEAT ADVISORY.
BY FRIDAY, A DEVELOPING TROUGH IN THE EASTERN PACIFIC COMES INTO THE
WEST COAST, AND A COOLING TREND WILL CAUSE TEMPERATURES TO DIP NEAR
AND BELOW SEASONAL AVERAGES. WEEKEND HIGHS RANGE FROM THE MIDDLE 70S
TO THE MIDDLE 80S IN THE INLAND VALLEYS AND THE MIDDLE 60S TO THE
MIDDLE 70S CLOSE TO THE BAYS. TEMPERATURES WILL RECOVER EARLY NEXT
WEEK AS THE TROUGH FLATTENS AND ENSEMBLE MODEL CLUSTER ANALYSIS
HINTS AT A RIDGE DEVELOPING SOMEWHERE WITHIN THE WESTERN UNITED
STATES, ALTHOUGH THE EXACT IMPACTS ARE NOT CERTAIN AT THIS POINT.
AVIATION
(18Z TAFS)
ISSUED AT 1107 AM PDT TUE SEP 22 2026
MVFR TO IFR CEILINGS ASSOCIATED WITH THE MARINE LAYER WILL GRADUALLY
SCATTER OUT IN THE NEXT COUPLE OF HOURS, RESULTING IN WIDESPREAD VFR
CONDITIONS AT MOST TERMINALS. LOW CONFIDENCE ON WHETHER HAF WILL SEE
THE SUN AS THERE MAY BE A BRIEF PERIOD OF SCATTERED CLOUDS BEFORE
BECOMING BKN AGAIN. THE USUAL DIURNAL ONSHORE WIND PATTERN PREVAILS
THROUGH THE AFTERNOON WITH A LIGHT SOUTH TO SOUTHWEST FLOW OVERNIGHT
ACROSS OUR REGION. THE MARINE LAYER WILL COMPRESS OVERNIGHT. EXACTLY
HOW MUCH IS UNCERTAIN. MODERATE CONFIDENCE FOR STS, LVK, SJC, AND
SFO TO REMAIN VFR THROUGH THE TAF CYCLE WITH ADVERTISED SCT DECKS
EARLY WEDNESDAY MORNING. THERE IS A 60-70% CHANCE FOR APC AND OAK TO
DEVELOP BKN CEILINGS GIVEN THEIR EXPOSED LOCATIONS, THOUGH IT MAY BE
INTERMITTENT DEPENDING ON THE MARINE LAYER DEPTH TONIGHT.
VICINITY OF SFO...VFR PREVAILS THIS AFTERNOON WITH LOW TO MEDIUM
CONFIDENCE ON THE RETURN OF MVFR CEILINGS TONIGHT. SHOULD CEILINGS
DEVELOP, THEY WILL LIKELY ROLL IN AROUND THE TIME OF THE SCT DECKS
AS ADVERTISED. OAK HAS A HIGHER PROBABILITY OF DEVELOPING MVFR
CEILINGS EARLY WEDNESDAY MORNING COMPARED TO SFO. WESTERLY WINDS
INCREASE TO MODERATE THIS AFTERNOON AND EASE TO A LIGHT
SOUTHWESTERLY FLOW WEDNESDAY MORNING BEFORE INCREASING AGAIN.
SFO BRIDGE APPROACH...CURRENT SATELLITE IMAGERY SHOWS A FINAL PUSH
OF STRATUS ACROSS THE BRIDGE, BUT SHOULD BECOME VFR IN THE NEXT HOUR
OR SO. PATCHY CLOUD COVER IS POSSIBLE OVER THE EASTERN SIDE OF THE
BRIDGE TONIGHT. OTHERWISE, SIMILAR TO SFO.
MONTEREY BAY TERMINALS...BORDERLINE MVFR-IFR CEILINGS LINGER THROUGH
THE NEXT COUPLE OF HOURS WITH A BRIEF PERIOD OF VFR CONDITIONS.
MEDIUM TO HIGH CONFIDENCE FOR AN EARLY ONSET OF IFR CEILINGS AROUND
4-7 PM PDT IMPACTING MRY FIRST AND THEN SNS. LOW CONFIDENCE ON
WHETHER CEILINGS WILL DROP TO LIFR TERRITORY EARLY WEDNESDAY
MORNING. FOR NOW, THE TAF ADVERTISES BORDERLINE IFR-LIFR WITH SLIGHT
IMPACTS TO VISIBILITY DUE TO MIST AND/OR DRIZZLE. ONSHORE WINDS
INCREASE TO 7-10 KT THIS AFTERNOON AND GRADUALLY BECOME LIGHT
SOUTHERLY BREEZES OVERNIGHT.
MARINE
(TODAY THROUGH SUNDAY)
ISSUED AT 904 AM PDT TUE SEP 22 2026
FRESH NORTHWEST BREEZES WITH STRONG GUSTS GRADUALLY DIMINISH
ACROSS THE SOUTHERN COASTAL WATERS BY WEDNESDAY MORNING. WIND
DRIVEN ROUGH SEAS ABATE TO MODERATE FOR A BRIEF PERIOD WEDNESDAY
NIGHT INTO THURSDAY WITH WIDESPREAD MODERATE NORTHWEST WINDS. BY
FRIDAY, WINDS INCREASE WITH BUILDING ROUGH SEAS.
FIRE WEATHER
ISSUED AT 434 AM PDT TUE SEP 22 2026
SOLID MARINE LAYER COVERAGE ALONG THE COAST AND SALINAS VALLEY
OVERNIGHT. SOUNDING AND PROFILERS PUT THE DEPTH OF THE MARINE
LAYER AROUND THE 2,000-2,500 FOOT RANGE. DEFINITELY SOME
COMPRESSION ON THE MARINE LAYER LEADING TO DRIZZLEFEST AROUND THE
AREA. SEEING SOME REDUCED VSBY TOO, WHICH MAY LEAD TO PATCHY FOG
EARLY THIS MORNING FOR CREWS DEPARTING ICP FOR TIMBER/PLASKETT.
ABOVE THE MARINE LAYER MODERATE TO EXCELLENT HUMIDITY RECOVERY
FOR THE MOST PART WITH THE DRIEST CONDITIONS ABOVE 3,000 FEET.
OTHERWISE, STILL VALID FOR A WARMING AND DRYING TREND KICKING OFF
TUESDAY WITH TEMPERATURES UP TO 10 DEGREES ABOVE NORMAL AND AREAS
OF MODERATE HEATRISK WEDNESDAY AND THURSDAY. THE MARINE LAYER WILL
COMPRESS BELOW 1,000 FEET DURING THIS WARM-UP WITH NOCTURNAL
DRYING EXPECTED ABOVE IT.
MM
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 5 AM PDT WEDNESDAY FOR PT ARENA TO PT
REYES 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 FROM 3 PM THIS AFTERNOON TO 3 AM PDT
WEDNESDAY FOR PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT THURSDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 5 AM PDT
WEDNESDAY FOR PIGEON PT TO PT PINOS 10-60 NM.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...NAVARRETE
MARINE...NAVARRETE
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