956
FXUS66 KMTR 031716
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1016 AM PDT SAT OCT 3 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1243 AM PDT SAT OCT 3 2026
- MODERATE TO MAJOR HEATRISK ACROSS THE BAY AREA AND CENTRAL
COAST SATURDAY AND SUNDAY
- MODERATE TO MAJOR HEATRISK ACROSS THE INTERIOR BAY AREA AND
CENTRAL COAST MONDAY THROUGH THURSDAY
- ELEVATED FIRE WEATHER CONDITIONS ACROSS THE HIGHER TERRAIN
THROUGH THURSDAY
SHORT TERM
ISSUED AT 1243 AM PDT SAT OCT 3 2026
(SATURDAY AND SUNDAY)
THE 00Z SOUNDING OBSERVED AN 850 MB TEMPERATURE OF 22.95 DEGREES
CELSIUS AND A 500 MB HEIGHT OF 5900 METERS, BOTH OF THESE ARE ABOVE
THE 90TH PERCENTILE. THE HEAT WILL PEAK THIS WEEKEND AS AN UPPER-
LEVEL LONGWAVE RIDGE DRIFTS IN FROM THE EASTERN PACIFIC OCEAN. A
HEAT ADVISORY WILL GO INTO EFFECT AT 11 AM SATURDAY AND RUN THROUGH
10 PM SUNDAY FOR MOST OF THE BAY AREA AND CENTRAL COAST. IT WAS
EXTENDED IN AREA TO INCLUDE THE CARMEL VALLEY, HOLLISTER VALLEY,
MARIN COASTAL RANGE, NORTHERN MONTEREY BAY, NORTHERN SALINAS VALLEY,
AND SAN FRANCISCO. NOW, THE ONLY PLACES THAT ARE NOT INCLUDED IS THE
NORTH BAY COAST, SAN FRANCISCO PENINSULA COAST, AND SOUTHERN
MONTEREY BAY; THIS IS BANKING ON A COMPRESSED MARINE LAYER KEEPING
THESE SPOTS COOL. IF THE COMPRESSED MARINE LAYER IS ABLE TO SURVIVE,
EXPECT REDUCED VISIBILITY FROM FOG ALONG THE COAST. IF IT IS NOT
ABLE TO SURVIVE, COASTAL CONDITIONS WILL BE HOTTER THAN CURRENTLY
FORECAST. MODERATE TO MAJOR HEATRISK WILL RESULT FROM MAXIMUM
TEMPERATURES 10 TO 20 DEGREES ABOVE NORMAL. MINIMUM TEMPERATURES 10
TO 20 DEGREES ABOVE NORMAL WITH WEAKER THAN NORMAL ONSHORE FLOW WILL
BRING LIMITED RELIEF OVERNIGHT, ALSO CONTRIBUTING TO HEATRISK. EVEN
LESS RELIEF IS EXPECTED IN THE HIGHER TERRAIN WHERE ELEVATED FIRE
WEATHER CONDITIONS CONTINUE WITH HOT AND DRY CONDITIONS, PROMINENT
THERMAL BELTING, AND PROLONGED BURN PERIODS.
LONG TERM
ISSUED AT 1243 AM PDT SAT OCT 3 2026
(MONDAY THROUGH FRIDAY)
THE HEAT ADVISORY WILL REMAIN IN EFFECT THROUGH 10 PM MONDAY FOR THE
INTERIOR BAY AREA AND CENTRAL COAST. UPPER-LEVEL SHORTWAVE TROUGHING
WILL UNDERCUT THE RIDGE AND BRING AN INCREASE IN ONSHORE FLOW
MONDAY; HOWEVER, THE INTERIOR WILL REMAIN HOT. GLOBAL ENSEMBLE
CLUSTERS ARE IN AGREEMENT THAT HEIGHTS WILL REBUILD TUESDAY AND PEAK
WEDNESDAY. WITH LITTLE CHANGE IN THE DAY-TO-DAY FORECAST AND THE
CUMULATIVE HEAT IMPACTS, WE COULD BE LOOKING AT AN EXTENDED HEAT
ADVISORY. THIS IS ESPECIALLY TRUE FOR THE EAST BAY AND SOUTH BAY
WHERE MAJOR HEATRISK IS LIKELY (60%+) THROUGH WEDNESDAY. THE MARINE
LAYER WILL REMAIN COMPRESSED DURING THIS TIME, KEEPING THE COAST
COOL AND LIKELY REDUCING VISIBILITY FROM FOG. ELEVATED FIRE WEATHER
CONDITIONS WILL CONTINUE IN THE HIGHER TERRAIN THROUGH THURSDAY FOR
HOT AND DRY CONDITIONS WITH PROMINENT THERMAL BELTING AND PROLONGED
BURN PERIODS. THURSDAY REMAINS UNCERTAIN ON RIDGE VS. TROUGH, BUT BY
FRIDAY IT IS LIKELY THAT HEIGHTS WILL BEGIN TO FALL.
AVIATION
(18Z TAFS)
ISSUED AT 1015 AM PDT SAT OCT 3 2026
HIGH PRESSURE STRENGTHENING OVER THE REGION WILL RESULT IN
CONTINUED VFR CONDITIONS THROUGHOUT THE DAY TODAY WITH WEAK
ONSHORE FLOW RETURNING BY MID-AFTERNOON BEFORE EASING OVERNIGHT.
THE GREATEST POTENTIAL FOR SUB-IFR CONDITIONS WILL BE AROUND THE
MONTEREY BAY TERMINALS LATE TONIGHT INTO EARLY SUNDAY MORNING,
HOWEVER CONFIDENCE IS LOW TO MODERATE.
VICINITY OF SFO...VFR. WEAK OFFSHORE WINDS CURRENTLY WITH WEAK
ONSHORE FLOW EXPECTED BY MID-AFTERNOON. WINDS EASE OVERNIGHT AND
INTO EARLY SUNDAY MORNING WITH GENERALLY HIGH CONFIDENCE OF VFR
CONDITIONS PERSISTING THROUGH THE TAF PERIOD.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR. MODERATE DRAINAGE WINDS CURRENTLY
AT SNS WILL SHIFT ONSHORE BY EARLY AFTERNOON AND PREVAIL THROUGH
THIS EVENING. THE GREATEST POTENTIAL FOR SUB-IFR CONDITIONS WILL
BE AT MRY LATE TONIGHT AND INTO EARLY SUNDAY MORNING, LESS
CONFIDENCE FOR SNS. ANY LOW CLOUDS AND/OR FOG THAT DOES DEVELOP IS
LIKELY TO DISSIPATE BY 15Z SUNDAY.
MARINE
(TODAY THROUGH THURSDAY)
ISSUED AT 1015 AM PDT SAT OCT 3 2026
NORTHERLY TO NORTHWESTERLY BREEZES REMAIN GENTLE TO MODERATE INTO
EARLY WEEK, ALLOWING FOR SLIGHT TO MODERATE SEAS TO PERSIST.
FIRE WEATHER
ISSUED AT 458 AM PDT SAT OCT 3 2026
HOT AND DRY CONDITIONS ARE FORECAST THROUGH NEXT WEEK, WHICH WILL
BE ACCOMPANIED WITH WEAK OFFSHORE FLOW. POOR TO VERY POOR
OVERNIGHT RECOVERY IS EXPECTED FOR THE THERMAL BELTS, GENERALLY
FOR ELEVATIONS ABOVE 1000-1500 FEET, LEADING TO ELEVATED FIRE
WEATHER CONDITIONS. THE MARINE LAYER IS EXPECTED TO BE CONFINED TO
THE IMMEDIATE COAST AND AROUND 500 FEET. A PATTERN CHANGE BEGINS
LATE THURSDAY INTO FRIDAY, WHICH MAY LEAD TO COOLER WEATHER AND
THE POTENTIAL FOR IMPROVED RH RECOVERY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...HEAT ADVISORY UNTIL 10 PM PDT SUNDAY FOR CAZ006-502-528-529.
HEAT ADVISORY UNTIL 10 PM PDT MONDAY FOR CAZ503-504-506-508-510-
512>518.
PZ...NONE.
SHORT TERM...SARMENT
LONG TERM....SARMENT
AVIATION...RGASS
MARINE...RGASS
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO
FOLLOW US ON FACEBOOK, X, AND YOUTUBE AT:
WWW.FACEBOOK.COM/NWSBAYAREA
X.COM/NWSBAYAREA
WWW.YOUTUBE.COM/NWSBAYAREA
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page