190
FXUS66 KMTR 301821
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1121 AM PDT THU APR 30 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1149 PM PDT WED APR 29 2026
- WARMING AND DRYING TREND CONTINUES INTO FRIDAY FOR AREAS AWAY
FROM THE COAST
- OVERNIGHT AND EARLY MORNING STRATUS REMAINS IN THE FORECAST AS
THE MARINE LAYER DEEPENS THIS WEEKEND
- COOLER CONDITIONS RETURN THIS WEEKEND WITH A CHANCE OF DRIZZLE
AND/OR LIGHT RAIN INTO EARLY NEXT WEEK
SHORT TERM
ISSUED AT 1149 PM PDT WED APR 29 2026
(TONIGHT THROUGH FRIDAY)
VERY SIMILAR CONDITIONS TO LAST NIGHT AT THIS TIME, AND VERY
SIMILAR NIGHT AHEAD. COASTAL STRATUS IS BUILDING ALONG THE SF
PENINSULA AND AROUND POINT REYES. THIS CLOUD COVER WILL BEGIN TO
PUSH INLAND OVER THE NEXT FEW HOURS FILLING AROUND THE BAYS AS
POCKETS OF FOG FORM IN THE VALLEYS ACROSS THE REGION.
AGAIN THIS IS A GOOD INDICATOR OF THE MARINE LAYER STAYING INTACT
DESPITE THE RIDGING PATTERN TO THE NORTH. THIS RIDGE HAS BEEN
RESPONSIBLE FOR THE WARMING TREND FOR THE MORE INLAND AREAS, WHILE A
CUTOFF LOW TO THE SOUTH HAS ALLOWED FOR THE MARINE LAYER STICK
AROUND AND KEEP THE COAST ON THE COOL SIDE. THE PRESSURE GRADIENT
BETWEEN THE RIDGE AND LOW HAS BEEN A BIG FACTOR IN THE BREEZINESS
IN THE MARINE ENVIRONMENT AND THE IMMEDIATE COAST.
THURSDAY SEES THE MARINE INFLUENCE KEEPING COASTAL AND SLIGHTLY
INLAND TEMPERATURES SIMILAR TO PREVIOUS DAYS, WITH A FEW SPOTS BEING
SLIGHTLY COOLER AS COASTALS STRATUS LINGERS INTO THE AFTERNOON IN A
FEW SPOT. THE MORE INLAND AREAS NOT AFFECTED BY THE MARINE LAYER
WILL CONTINUE THE WARMING TREND. HIGHS IN THE FAR INTERIOR LOOK TO
PEAK IN THE LOW TO MID 80S, AND THE COAST WILL STAY AROUND 60
DEGREES, AND ALL THE AREAS IN BETWEEN WILL STICK TO THE 70S.
LONG TERM
ISSUED AT 1149 PM PDT WED APR 29 2026
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
COASTAL CLOUD COVER WILL LINGER INTO THE AFTERNOON AGAIN ON FRIDAY,
AND THE MARINE LAYER STAYS STRONG, SO THE COAST WILL STAY ON THE
COOL SIDE. THE BEGINNING OF A SHIFT IN THE UPPER LEVEL PATTERN WILL
PREVENT THE NORTH BAY FROM CONTINUED WARMING, WITH MOST AREAS SEEING
SIMILAR HIGHS TO THURSDAY, IF NOT SLIGHTLY COOLER. OTHER MORE INLAND
AREAS WILL SEE THE WARMING TREND PEAK EXPECT MORE AREAS TO BREAK
INTO THE 80S AND THE MID TO UPPER 80S IN THE FAR INTERIOR WITH MAYBE
A FEW SPOTS BREAKING 90 DEGREES IN SOUTHERN MONTEREY CO.
THE PATTERN CHANGE REALLY GOES IN EFFECT FRIDAY NIGHT AS THE RIDGE
PUSHES EAST AND ANOTHER LOW PRESSURE AND TROUGH BUILDS ALONG THE
PACIFIC COAST. HIGHER CLOUDS WILL BUILD THAT NIGHT, AND THE
REDUCTION IN PRESSURE WILL ALLOW FOR THE MARINE LAYER TO EXPAND AND
PUSH FARTHER INLAND. THESE FACTORS, ALONG WITH INCREASING ONSHORE
FLOW, WILL ALLOW FOR A STRONG COOLING TREND THROUGH THE WEEKEND.
ALONG WITH COOLING TEMPERATURES, THE LOW PRESSURE LOOKS TO MOVE
INLAND OVER THE BAY AREA SUNDAY NIGHT. THIS WILL START WITH DRIZZLY
CONDITIONS EARLY SUNDAY WITH CHANCES FOR SCATTERED LIGHT RAIN
POSSIBLE LATER THAT NIGHT AS THE LOW CENTERS OVER THE REGION. LIGHT
RAIN AND WIDESPREAD DRIZZLE CHANCES LOOK TO LAST THROUGH MOST OF
MONDAY WITH SOME POTENTIAL FOR THE LOW TO SLOW ITS MOMENTUM AND
OFFER PRECIP CHANCE INTO TUESDAY BEFORE EXITING.
WHILE RAIN CHANCES ARE GOOD, OVERALL RAINFALL AMOUNTS WILL BE LIGHT.
MOST AREAS WILL ONLY SEE TRACE AMOUNTS TO A FEW HUNDREDTHS OF AN
INCH OF RAIN FROM THIS SYSTEM.
BEHIND IT, MOST MODELS HINT AT ANOTHER RIDGE BUILDING QUICKLY IN THE
MIDWEEK. CLOUD COVER WILL ERODE, THE MARINE LAYER WILL COMPRESS, AND
TEMPERATURES WILL WARM AGAIN.
AVIATION
(18Z TAFS)
ISSUED AT 1117 AM PDT THU APR 30 2026
COASTAL LOCATIONS ARE HOLDING ON TO MVFR CIGS WITH VFR RETURNING
TO THE REMAINDER OF THE REGION. ONSHORE WINDS WILL INCREASE THIS
AFTERNOON AND PERSIST THROUGH ABOUT SUNSET BEFORE DIMINISHING
SLIGHTLY. THE MARINE LAYER IS FORECAST TO DEEPEN OVERNIGHT TO
AROUND 1,500 FT ALLOWING FOR A DEEPER INLAND PENETRATION OF
STRATUS. THUS, IFR/MVFR CONDITIONS ARE MOST LIKELY LATE THIS
EVENING AND INTO FRIDAY MORNING. THE GREATEST POTENTIAL FOR LIFR
CONDITIONS ARE IN THE NORTH BAY, SAN FRANCISCO PENINSULA, AND
AROUND THE MONTEREY BAY TERMINALS LATE TONIGHT AND INTO FRIDAY
MORNING. FAIRLY HIGH CONFIDENCE IN SUB-MVFR WITH MEDIUM CONFIDENCE
IN LIFR OVERNIGHT. ONSHORE WINDS INCREASE ONCE AGAIN FRIDAY
AFTERNOON WITH INLAND CONDITIONS RETURNING TO VFR BETWEEN 17Z-20Z.
VICINITY OF SFO...WESTERLY WINDS DOMINATE THIS TAF PERIOD WITH
BREEZY CONDITIONS EXPECTED THURSDAY AFTERNOON INTO THE EVENING.
THE WINDS SHOULD DECREASE OVER NIGHT AND SKY COVER WILL BEGIN TO
TRANSITION FROM VFR INTO MVFR AROUND 03Z FRIDAY. MODERATE
CONFIDENCE THAT MVFR CIGS WILL PERSIST AROUND 09Z FRIDAY AND
REMAIN BEFORE MIXING OUT BY LATE MORNING FRIDAY WITH THE HELP OF
INCREASED WINDS AND DAYTIME HEATING. THERE MAY BE A FEW LOWER
CLOUD DECKS IN THE MIX AROUND 14Z, BUT CONFIDENCE IS TOO LOW TO
CLAIM AS A PREVAILING CONDITION.
SFO BRIDGE APPROACH...VFR CONDITIONS WILL PREVAIL UNTIL THE
EVENING WHEN MVFR CIGS BEGIN TO IMPACT THE BAY. WINDS WILL HAVE A
NW TO W COMPONENT THROUGH THE TAF PERIOD WITH THE WIND SPEED TREND
TO MATCH THAT OF SFO'S. MVFR CIGS ARE EXPECTED AROUND 04Z THOUGH
WILL BE SLIGHTLY HIGHER AT TIMES THAN THOSE FOUND DIRECTLY OVER
SFO. THE STRATUS DECK SHOULD CLEAR BY LATE FRIDAY MORNING.
MONTEREY BAY TERMINALS...MVFR AT KMRY, WHILE KSNS HAS RETURNED TO
VFR. THERE IS MEDIUM TO HIGH CONFIDENCE FOR SEVERAL HOURS OF VFR
CONDITIONS AT BOTH TERMINALS BEFORE MVFR CIGS RETURN EARLY
EVENING. CIGS LOWER TO IFR (40%-80%) AND POTENTIALLY AS LOW AS
LIFR (20%-40%) LATE TONIGHT OR EARLY FRIDAY MORNING AND PERSIST
THROUGH MUCH OF THE MORNING. CIGS ARE THEN FORECAST TO GRADUALLY
LIFT AND SCATTER OUT BETWEEN 16Z-18Z FRIDAY.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 1117 AM PDT THU APR 30 2026
A FRESH TO STRONG NORTHWEST BREEZE CONTINUES OVER THE COASTAL
WATERS INTO THIS WEEKEND. WINDS WILL BE STRONGEST OVER THE
NORTHERN OUTER WATERS WHERE WINDS WILL RESULT IN MODERATE SEAS
BUILDING TO BETWEEN 10 TO 12 FEET. WINDS DECREASE AND SEAS SUBSIDE
BY LATE SATURDAY WITH CONDITIONS IMPROVING THROUGH THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR PIGEON PT TO PT PINOS 0-10 NM-PT ARENA TO PT
REYES 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PIGEON PT
TO PT PINOS 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT FRIDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...MURDOCK
LONG TERM....MURDOCK
AVIATION...RGASS/AN
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