336
FXUS66 KMTR 200426
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
925 PM PDT SAT SEP 19 2026
..NEW KEY MESSAGES, SHORT TERM, LONG TERM, AVIATION
KEY MESSAGES
UPDATED AT 925 PM PDT SAT SEP 19 2026
- BRIEF COOLING SUNDAY THROUGH MONDAY
- MORE SUBSTANTIAL WARMING TREND TUESDAY THROUGH THURSDAY
SHORT TERM
ISSUED AT 925 PM PDT SAT SEP 19 2026
(TONIGHT THROUGH MONDAY NIGHT)
RESIDUAL POLAR JET STREAM WINDS WILL MERGE WITH THE SUBTROPICAL JET
STREAM AT THE BASE OF A WEAK 500 MB LOW CURRENTLY ~ 500 MILES WEST
OF MONTEREY AND MOVE THE LOW EASTWARD ACROSS OUR FORECAST AREA
LATER SUNDAY THROUGH MONDAY. COOL ONSHORE BREEZES WILL HELP KEEP
TEMPERATURES BELOW NORMAL. DAYTIME HIGHS SUNDAY WILL BE COOLER
THAN TYPICAL FOR SEP 20TH WITH HIGHS IN THE 60S COASTSIDE/BAYSIDE
TO THE 70S AND 80S INLAND. HIGHS MONDAY WILL BE ABOUT THE SAME AS
ON SUNDAY. A FEW PATCHES OF LATE NIGHT AND MORNING LIGHT DRIZZLE
MAY FORM IN THE COOLED AIR NEAR SURFACE TO ALOFT.
LONG TERM
ISSUED AT 925 PM PDT SAT SEP 19 2026
(TUESDAY THROUGH NEXT SATURDAY)
500 MB LOW AMPLITUDE RIDGING WILL DEVELOP TUESDAY INTO EARLY
THURSDAY. THIS WILL BRING A WARMING TREND HERE DURING THESE THREE
DAYS, WHICH WILL HELP PUSH DAYTIME HIGHS UP TO THE 90S/100 INLAND
WED-THU (COOLER AT THE COASTLINE AND BAYS). THE PATTERN ACROSS
THE NORTH PACIFIC TO THE WESTERN CONUS IS PROGRESSIVE, WHICH LOWERS
CONFIDENCE A LITTLE IN THE TIMING OF 500 MB RIDGING RESIDENCE TIME
AND THIS MAY INFLUENCE THE DURATION OF WARM/HOT WEATHER CURRENTLY
FORECAST FOR MID NEXT WEEK. STAY TUNED TO THE LATEST UPDATES.
AVIATION
(00Z TAFS)
ISSUED AT 921 PM PDT SAT SEP 19 2026
VFR PREVAILS EXCEPT FOR COASTAL STRATUS AND MIST/FOG /IFR/. ONSHORE
WINDS WILL BRING STRATUS AND MIST/FOG /IFR-LIFR/ INLAND TONIGHT AND
SUNDAY MORNING. CONDITIONS IMPROVE TO MVFR-VFR NEAR THE COASTLINE
SUNDAY AFTERNOON WHILE VFR CONTINUES FARTHEST INLAND. STRATUS AND
MIST/FOG /IFR-LIFR/ RETURN INLAND SUNDAY NIGHT AND EARLY MONDAY
MORNING.
VICINITY OF SFO...VFR AND A WEST WIND NEAR 15 KNOTS DURING THE
EVENING, WEST WIND THEN DIMINISHING TO NEAR 10 KNOTS TONIGHT AND
SUNDAY MORNING. MVFR STRATUS CEILING FORECAST 07Z-19Z SUNDAY.
STRATUS /MVFR/ REDEVELOPS SUNDAY EVENING AND NIGHT. WEST WIND 10
TO 15 KNOTS SUNDAY AFTERNOON AND EVENING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...STRATUS AND MIST/FOG /IFR-LIFR/ ARE NEARBY
AND WILL MOVE INLAND TONIGHT AND SUNDAY MORNING. CONDITIONS IMPROVE
TO MVFR-VFR BY LATE SUNDAY MORNING AND AFTERNOON. STRATUS /IFR-LIFR/
REDEVELOPS SUNDAY NIGHT. MAINLY ONSHORE WINDS 5 TO 15 KNOTS.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 828 PM PDT SAT SEP 19 2026
MODERATE NORTHWEST WINDS WILL CONTINUE TONIGHT INTO SUNDAY THEN
INCREASE SUNDAY AFTERNOON AND EVENING AS A WEAK UPPER LOW
APPROACHES THE REGION. FRESH WIND WAVE SEAS WILL CONTINUE OVER A
LONG PERIOD SOUTHERLY SWELL. HIGH PRESSURE BUILDS TUESDAY THROUGH
THURSDAY WITH WINDS EASING NEAR SHORE.
FIRE WEATHER
ISSUED AT 1229 PM PDT SAT SEP 19 2026
THE MARINE LAYER IS AROUND 1,500 FEET DEEP AND COMPRESSING. THERE
WERE SOME OFFSHORE WINDS THIS MORNING, BUT THE SEA BREEZE IS
TAKING OVER AS THE OFFSHORE GRADIENT RELAXES. TODAY WILL BE WARMER
AND SLIGHTLY DRIER THAN RECENT DAYS, ALTHOUGH WINDS WILL BE
LIGHTER THROUGH THE PEAK BURN PERIOD. COOLER AND MORE HUMID
CONDITIONS ARRIVE SUNDAY-MONDAY BEFORE A LONGER WARMING TREND
TUESDAY THROUGH THURSDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM PDT SUNDAY FOR PT ARENA TO PT
REYES 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SUNDAY FOR PIGEON PT TO PT
PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT SUNDAY FOR PIGEON PT
TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT MONDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT MONDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...CANEPA
LONG TERM....CANEPA
AVIATION...CANEPA
MARINE...RW/CANEPA
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