277
FXUS66 KMTR 140026
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
526 PM PDT SAT SEP 13 2025
..NEW SHORT TERM, LONG TERM, MARINE
KEY MESSAGES
UPDATED AT 358 PM PDT SAT SEP 13 2025
- TEMPERATURES AROUND OR SLIGHTLY BELOW NORMAL ON SUNDAY
- MUCH WARMER TEMPERATURES FOR THE FIRST HALF OF THE UPCOMING WORK
WEEK.
- MODERATE HEATRISK POSSIBLE INLAND MONDAY THROUGH WEDNESDAY
- PATTERN CHANGE POSSIBLE LATE WEEK.
SHORT TERM
ISSUED AT 358 PM PDT SAT SEP 13 2025
(THIS EVENING THROUGH SUNDAY)
A SIMILAR FORECAST IS ON TAP FOR TONIGHT AND SUNDAY, AS MAINLY ZONAL
FLOW SITS OVER US WHILE A QUICK MOVING UPPER LEVEL TROUGH SWINGS
OVER THE PACNW. STRATUS SHOULD MAKE A RETURN INLAND TONIGHT, WITH
THE MARINE LAYER RANGING FROM 1500-2000FT. TEMPS TONIGHT WILL RANGE
FROM THE LOW TO MID 50S, WHERE CLOUD COVER EITHER TAKES LONGER TO
APPEAR OR NOT FORM AT ALL, TO THE MID 50S TO LOW 60S ELSEWHERE.
TOMORROW, STRATUS ERODES INLAND AND RETREATS TO THE COAST. HIGHS
WILL BE IN THE MID 60S TO MID 70S NEAR THE COAST, SPREAD ACROSS THE
80S FOR MUCH OF THE INTERIOR, WITH THE LOW 90S POSSIBLE FOR INTERIOR
AND SOUTHERN MONTEREY AND SAN BENITO COUNTIES.
LONG TERM
ISSUED AT 358 PM PDT SAT SEP 13 2025
(SUNDAY NIGHT THROUGH NEXT FRIDAY)
UPPER LEVEL RIDGING TAKES OVER THE FORECAST FOR THE FIRST PART OF
THE EXTENDED PERIOD, LEADING TO A WARMING AND DRYING TREND THROUGH
WEDNESDAY. HIGH TEMPERATURES WILL NEAR NORMAL ALONG THE IMMEDIATE
COAST TO UP TO 15 DEGREES ABOVE NORMAL INLAND. AFTER THAT, THE
PATTERN STARTS TO DIVERGE MID TO LATE WEEK. ENSEMBLES SHOW AN UPPER
LEVEL TROUGH IN THE NORTH EASTERN PACIFIC APPROACH THE PACNW PUSHING
RIDGING EASTWARDS BY THURSDAY OR FRIDAY AND DEEPENING ALONG THE WEST
COAST INTO THE WEEKEND. DETERMINISTIC MODELS AND SOME ENSEMBLES SHOW
A SLUG OF MOISTURE COMING IN FROM THE SOUTH. UNCERTAINTY REMAINS
HIGH IN THE EXTENDED FORECAST, ESPECIALLY IN REGARDS TO ANY LOW OR
TROUGH. THIS MAY LEAD TO UNSETTLED WEATHER LATER IN THE WEEK.
AVIATION
(21Z TAFS)
ISSUED AT 125 PM PDT SAT SEP 13 2025
KSFO AND KOAK CONTINUE TO SEE MVFR CONDITIONS EARLY THIS AFTERNOON
AS WELL AS KMRY AND KSNS. WE HAVE A MODERATE PROBABILITY FOR A
FEW HOURS OF CLEARING LATER THIS AFTERNOON BEFORE IFR/MVFR
CONDITIONS RETURN. HOWEVER, THE FAR INTERIOR AREAS OF THE REGION
RETURNED TO VFR AS OF LATE MORNING.
ONSHORE WINDS WILL INCREASE BEFORE EASING AFTER SUNSET AND MORE
SO INTO SUNDAY MORNING. GENERALLY MODERATE CONFIDENCE FOR IFR/MVFR
CONDITIONS TO RETURN LATE AFTERNOON ACROSS THE MONTEREY BAY
REGION AND LATE EVENING ACROSS THE BAY AREA TERMINALS. THE HRRR
SHOWS LITTLE INDICATION OF LOW CEILINGS RETURNING, ESPECIALLY OVER
THE BAY AREA TERMINALS. HOWEVER, OTHER GUIDANCE INCLUDING THE
LAMP SHOWS A RETURN IN THE AFOREMENTIONED TIMEFRAME. THIS IS
LIKELY DUE TO A DRY FRONTAL BOUNDARY APPROACHING FROM THE NORTH
LATE TONIGHT INTO SUNDAY MORNING.
VICINITY OF SFO...HIGH CONFIDENCE FOR ONSHORE WINDS TO INCREASE THIS
AFTERNOON BEFORE EASING INTO EARLY SUNDAY MORNING. MODERATE
CONFIDENCE FOR MVFR CONDITIONS TO RETURN LATE THIS EVENING AND
PERSIST INTO MID-MORNING ON SUNDAY. LOW CONFIDENCE FOR SUB-MVFR
CONDITIONS EARLY SUNDAY MORNING. EARLIER CLEARING IS EXPECTED SUNDAY
MORNING BETWEEN 16Z-18Z AS THE MARINE LAYER BECOMES MIXED OUT BY THE
APPROACHING DRY FRONTAL BOUNDARY. ONSHORE WINDS INCREASE ONCE AGAIN
SUNDAY AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...MODERATE CONFIDENCE FOR VFR CONDITIONS
TO RETURN BRIEFLY THIS AFTERNOON WITH INCREASING ONSHORE WINDS.
MODERATE CONFIDENCE FOR IFR/MVFR CEILINGS RETURN LATE AFTERNOON
AND PERSIST THROUGH THE NIGHT AS WINDS EASE.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 358 PM PDT SAT SEP 13 2025
NORTHWESTERLY WINDS ARE FORECAST TO INCREASE SATURDAY AFTERNOON
WITH FRESH TO STRONG BREEZES ALONG PROMINENT COASTAL JET AREAS.
MODERATE SEAS PERSIST, ESPECIALLY OFFSHORE. MORE WIDESPREAD FRESH
TO STRONG BREEZES BUILD ACROSS THE REST OF THE WATERS INTO SUNDAY
AFTERNOON BEFORE SUBSIDING INTO THE BEGINNING OF NEXT WEEK.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT SUNDAY FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SUNDAY FOR PT ARENA TO PT
REYES 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM SUNDAY TO 3 AM PDT MONDAY FOR PT
ARENA TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT MONDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...JM
LONG TERM....JM
AVIATION...RGASS
MARINE...MURDOCK
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