759
FXUS66 KMTR 201119
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
419 AM PDT SUN SEP 20 2026
..NEW AVIATION, MARINE, FIRE WEATHER
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
(12Z TAFS)
ISSUED AT 416 AM PDT SUN SEP 20 2026
CURRENTLY LIFR-MVFR WITH HIGH CLOUDS STREAMING IN. IFR-MVFR CEILINGS
WILL PREVAIL THROUGH LATE-MORNING BEFORE STRATUS RETREATS TO THE
COAST. CONFIDENCE IS DECREASING IN ANY FOG DEVELOPMENT THIS MORNING.
MODERATE TO HIGH CONFIDENCE IN IFR-MVFR CEILINGS RETURNING TO ALL
TERMINALS TONIGHT. DRIZZLE WILL BE POSSIBLE IN THE MORNINGS. DIURNAL
WINDS WILL PREVAIL.
VICINITY OF SFO...CURRENTLY MVFR WITH WESTERLY FLOW. HIGH CONFIDENCE
IN A CEILING ON THE CUSP OF IFR/MVFR PREVAILING THROUGH LATE-
MORNING. HIGH (80%) CONFIDENCE IN AN MVFR CEILING RETURNING
TONIGHT. DIURNAL WINDS WILL PREVAIL.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CURRENTLY IFR WITH WESTERLY FLOW AT MRY AND
IFR WITH SOUTHWESTERLY FLOW AT SNS. IFR WILL PREVAIL THROUGH THE
MORNING WITH STRATUS RETREATING TO THE COAST DURING THE AFTERNOON.
THE CLOSE PROXIMITY MAY KEEP MRY SUB-VFR THROUGH THE TAF PERIOD WITH
AN EARLY RETURN SLATED TONIGHT. DIURNAL WINDS WILL PREVAIL.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 416 AM PDT SUN SEP 20 2026
FRESH TO STRONG NORTHERLY BREEZES WILL CREATE HAZARDOUS CONDITIONS
FOR SMALL CRAFT ACROSS MOST OF THE COASTAL WATERS THROUGH MONDAY
MORNING. MODERATE TO FRESH NORTHERLY BREEZES WILL PREVAIL TUESDAY
THROUGH THURSDAY WITH LOCALLY STRONG BREEZES ACROSS THE NORTHERN
OUTER WATERS. SLIGHT TO MODERATE SEAS WILL PREVAIL THROUGH MONDAY,
BUILDING TO BECOME MODERATE TO ROUGH TUESDAY THROUGH THURSDAY.
FIRE WEATHER
ISSUED AT 416 AM PDT SUN SEP 20 2026
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES, DIURNAL WINDS, A DEEP
MARINE LAYER, AND A CHANCE FOR DRIZZLE ARE ON TAP FOR SUNDAY AND
MONDAY. WARMING AND DRYING TREND KICKS OFF TUESDAY WITH TEMPERATURES
UP TO 15 DEGREES ABOVE NORMAL BY THURSDAY. AREAS OF MODERATE
HEATRISK ARE EXPECTED AS A RESULT WEDNESDAY AND THURSDAY. THE MARINE
LAYER WILL COMPRESS BELOW 1,000 FEET DURING THIS WARM-UP WITH
NOCTURNAL DRYING EXPECTED ABOVE IT. DIURNAL WINDS WILL PREVAIL;
HOWEVER, THEY WILL BE WEAKER THAN THE PRECEDING DAYS.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM PDT THIS MORNING 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 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...SARMENT
MARINE...SARMENT
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