333
FXUS66 KMTR 041150
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
350 AM PST TUE NOV 4 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 257 AM PST TUE NOV 4 2025
- WIND GUSTS OF 45 TO 65 MPH ARE FORECAST FOR PORTIONS OF THE
NORTH BAY, EAST BAY, SF BAY, AND SANTA CRUZ MOUNTAINS.
- LOW POTENTIAL FOR NUISANCE FLOODING IN THE NORTH BAY, BUT
MODERATE RAINFALL WILL BE LARGELY BENEFICIAL.
- THUNDERSTORM CHANCES REMAIN AROUND 10 TO 20 PERCENT WITH THE
MAIN HAZARDS BEING POCKETS OF HEAVIER RAINFALL AND ENHANCED
OUTFLOW WINDS.
SHORT TERM
ISSUED AT 257 AM PST TUE NOV 4 2025
(TODAY AND TONIGHT)
QUIET WEATHER TO START THE DAY TODAY WILL TRANSITION TO MORE
TURBULENT CONDITIONS TONIGHT AND INTO THE DAY ON WEDNESDAY. HIGH
CLOUDS CONTINUE TO FILTER IN OVERHEAD ACROSS THE NORTH BAY AND
THIS SHOULD CURTAIL THE THREAT FOR WIDESPREAD DENSE FOG (AND
PERHAPS FOG IN GENERAL). FARTHER SOUTH, THE LACK OF MID AND UPPER
LEVEL CLOUDS HAS FACILITATED MORE IN THE WAY OF RADIATIVE
COOLING AND WE'RE STARTING TO SEE SOME SITES DIP DOWN TO 1/2 MILE.
TRENDS WILL BE MONITORED THIS MORNING FOR A SHORT-FUSED DENSE FOG
ADVISORY (WOULD BE THE SC MOUNTAINS AND SALINAS VALLEY). FOG
SHOULD MIX OUT RAPIDLY BY MID TO LATE MORNING.
OUR WELL ADVERTISED UPPER LOW WILL INCH TOWARD NORTHERN
CALIFORNIA THROUGH THE DAY. AS IT DOES, IT'LL INDUCE PRESSURE
FALLS AND TIGHTEN THE SURFACE PRESSURE/HEIGHT GRADIENT. IN
RESPONSE, SOUTHERLY WINDS WILL RAMP UP, ESPECIALLY AFTER 00Z
ACROSS MARINE ZONES AND ADJACENT COASTAL REGIONS. ACROSS THE
SOUTHERN BIG SUR COAST, THERE WILL LIKELY BE SUFFICIENT ASCENT FOR
SOME WAA CONVECTION AND AFTER DISCUSSION WITH LOX, OPTED TO ADD
IN SOME SHOWERS.
THE LARGEST IMPACT WITH THIS SYSTEM IS ANTICIPATED TO BE THE
WIND. THE GENERAL TIMELINE FOR WINDS WILL BE FROM ROUGHLY 10PM
TONIGHT THROUGH 4PM WEDNESDAY. OVER THE LAST FEW DAYS, MODEL
GUIDANCE HAS COME INTO GREATER AGREEMENT WITH REGARD TO PLACEMENT
OF THE GREATEST CORRIDOR OF WINDS WILL RESIDE. JUST ABOUT ALL
DETERMINISTIC GUIDANCE INDICATES THAT A BELT OF 50 TO 60 KNOT FLOW
WILL NOSE IN FROM THE SOUTHWEST ACROSS THE SONOMA AND MARIN
COASTLINE. AT THE SURFACE, OUR TRUSTY MTRWRF AND PG&E/SJSU WRFS
SUPPORT SURFACE WIND GUSTS IN EXCESS OF 60 MPH FOR THE PACIFIC
COAST NORTH OF THE GOLDEN GATE STRAIT AND I'VE UPGRADED THIS
REGION TO A HIGH WIND WARNING FOR WIND GUSTS OF 60 TO 65 MPH WHICH
ALIGNS WITH THE CORRIDOR OF HIGH 925MB WINDS. TAKING AN
EXAMINATION AT SOME THE EXTREME FORECAST INDEX TOOLS, THERE'S A
VERY STRONG SIGNAL THAT THE EPS ENSEMBLE FORECAST DISTRIBUTION IS
SUBSTANTIALLY HIGHER THAN THE MODEL'S CLIMATOLOGY. IN FACT THERE'S
SOME INDICATION THAT A FEW OF THE EPS ENSEMBLE MEMBERS ARE QUITE
ANOMALOUS/EXTREME. WHAT THIS TRANSLATES TO IS A POTENTIAL FOR
65-70MPH WIND GUSTS IN SPOTS.
AREAS SOUTH OF THE GOLDEN GATE ARE ON THE FRINGES OF THE
AFOREMENTIONED 925MB JET MAX, BUT WIND GUSTS IN THE 45 TO 55 MPH
(AND THUS A WIND ADVISORY) ARE ADVERTISED FOR SF, THE SAN MATEO
PENINSULA, EAST BAY, AND SANTA CRUZ MOUNTAINS, THOUGH IT'S NOT OUT
OF THE REALM OF POSSIBILITY THAT SOME OF THESE AREAS MAY NEED TO
BE ADDED TO THE HIGH WIND WARNING, ESPECIALLY IF THE CORRIDOR OF
STRONGEST WINDS SHIFTS SOUTHWARD. REGARDLESS OF HIGH WIND WARNING
OR WIND ADVISORY, INDIVIDUALS SHOULD SECURE ANY LOOSE OUTDOOR
ARTICLES/DECOR AND ANTICIPATE DRIVING DIFFICULTY FOR HIGH-PROFILE
AND LIGHTWEIGHT VEHICLES (ESPECIALLY ON EAST-WEST ORIENTED
ROADWAYS). IN ADDITION, THERE WILL BE THE POTENTIAL FOR SPORADIC
POWER OUTAGES, PARTICULARLY ACROSS THE PACIFIC COAST NEAR/NORTH OF
THE GOLDEN GATE.
LONG TERM
ISSUED AT 257 AM PST TUE NOV 4 2025
(WEDNESDAY THROUGH MONDAY)
POTENTIALLY ENHANCING WINDS VIA PRECIPITATION LOADING WILL BE
POCKETS OF MODERATE TO AT TIMES HEAVY RAINFALL. THIS WILL BE MOST
PROBABLE ACROSS THE NORTH BAY WHERE INSTABILITY IS FORECAST TO BE
THE GREATEST. IN FACT, FORECAST SOUNDINGS AND HI-RES NWP INDICATE
MEAGER, BUT SUFFICIENT AMOUNTS OF MUCAPE OF AROUND 100-250 J/KG
ACROSS THE NORTH BAY AND THE THUNDER POTENTIAL IS LARGELY CONFINED
TO THIS REGION AND ADJACENT WATERS. THE MAIN HAZARD WITH STORMS
WILL BE BURSTS OF STRONGER WINDS AND HEAVIER PRECIPITATION. WHILE
HEAVY RAINFALL IS POSSIBLE, THE POTENTIAL FOR WIDESPREAD FLOODING
APPEARS TO BE ON THE LOW SIDE FOR A COUPLE OF REASONS. 1) NEAR
SURFACE SOIL MOISTURES ARE RUNNING NEAR OR BELOW NORMAL PER NASA
SPORT OUTPUT, AND 2) THE PROGRESSIVE NATURE OF THIS SYSTEM SHOULD
MINIMIZE THE POTENTIAL FOR TRAINING THUNDERSTORMS. EXAMINATION OF
EXPERIMENTAL FLOOD MAPPING AS WELL AS THE HYDROLOGIC FORECAST
ENSEMBLE SYSTEM INDICATES LITTLE TO NO RESPONSES ACROSS THE MAIN
STEM RIVERS. THAT SAID, SOME OF THE MORE HEFTIER PRECIPITATION
RATES WILL TRANSPIRE DURING THE WEDNESDAY MORNING COMMUTE AND THIS
MAY RESULT IN TRAFFIC IMPACTS AS WATER MIXES WITH OILS IN
ROADWAYS AND PONDING/NUISANCE FLOODING TAKES PLACE IN URBAN/POOR
DRAINAGE AREAS. AGAIN, THE SYSTEM APPEARS THAT IT'LL REMAIN
PROGRESSIVE AND WE DON'T ANTICIPATE A HIGH POTENTIAL FOR
STALLING/TRAINING OF PRECIPITATION BANDS.
OVERALL RAINFALL AMOUNTS REMAIN SOMEWHAT CONSISTENT WITH PREVIOUS
FORECAST ITERATIONS, THOUGH THERE HAVE BEEN SOME ADJUSTMENTS
UPWARD IN THE HIGHER TERRAIN/FAVORED COASTAL REGIONS. NORTH BAY
RAIN AMOUNTS APPEAR THAT THEY'LL STILL AVERAGE ANYWHERE BETWEEN
0.50" IN THE 'RAIN SHADOWED' AREAS TO THE 1-2.5" RANGE ACROSS THE
HIGHER TERRAIN. SOME OF THE MORE PROMINENT NORTH BAY MOUNTAINS MAY
BE THE RECIPIENTS OF MORE OPTIMAL UPSLOPE FLOW WITH VALUES JUST
UNDER 3". WE'LL NEED TO POTENTIALLY MAKE SOME LAST MINUTE
REFINEMENTS TO QPF AS THERE ARE SOME MEANINGFUL PROBABILITIES OF
OVER 3" AMOUNTS ACROSS COASTAL SONOMA COUNTY BETWEEN SEA RANCH AND
BODEGA BAY. FARTHER SOUTH, RAIN AMOUNTS AVERAGE BETWEEN 0.25" TO
0.75" ACROSS THE BAY AREA AND CENTRAL COAST, WITH AMOUNTS OVER 1"
ACROSS THE SANTA CRUZ MOUNTAINS, SANTA LUCIA RANGE, AND BIG SUR
COAST.
PRECIPITATION IS ANTICIPATED TO TAPER OFF THROUGH WEDNESDAY
NIGHT. RAPID CLEARING IN THE WAKE OF THE PRECIPITATION AND
DIMINISHING WINDS MAY SET THE STAGE FOR A DECENT RADIATION FOG
EVENT, ESPECIALLY ACROSS THE NORTH BAY WHERE THE HEAVIEST RAINFALL
IS ANTICIPATED. HOWEVER, THIS MAY BE MODULATED BY LINGERING CLOUD
COVER, WIND SPEEDS AND/OR THE AMOUNT OF DRY AIR THAT FILTERS IN
BEHIND A FRONT.
THE WEATHER PATTERN APPEARS THAT IT'LL REMAIN PROGRESSIVE WITH
LARGELY ZONAL FLOW ANTICIPATED AS WE ROUND OUT THE FIRST FULL WEEK
OF NOVEMBER. THERE ARE SOME HINTS AT A FEW PERTURBATIONS RIPPLING
THROUGH THE FLOW THAT MAY GIVE THE NORTH BAY A FEW OPPORTUNITIES
FOR ADDITIONAL LIGHT RAINFALL.
AVIATION
(12Z TAFS)
ISSUED AT 347 AM PST TUE NOV 4 2025
CURRENTLY A MIXED BAG OF VLIFR-VFR AT THE TERMINALS WITH DENSE FOG
BEING REPORTED IN MONTEREY BAY. OTHERWISE, HIGH-END MVFR TO LOW-END
VFR CEILINGS ARE BLANKETING MUCH OF THE REGION. LOW-END VFR CEILINGS
WILL LIKELY LINGER THROUGH THE TAF PERIOD, ESPECIALLY FOR THE NORTH
BAY. CEILINGS WILL LOWER THROUGH THE DAY WITH THE APPROACHING COLD
FRONT. SOUTHERLY WINDS WILL INCREASE THROUGH THE MORNING, BECOMING
STRONG AND GUSTY THIS AFTERNOON WITH THE PASSAGE OF THE COLD FRONT.
NO LOW-LEVEL WIND SHEAR IS EXPECTED WITH SOUTHERLY WINDS AT LEAST
UP TO FL020, BUT A BUMPY RIDE CAN STILL BE EXPECTED. RAIN
APPROACHES THE NORTH BAY AND VICINITY OF SFO TERMINALS TOWARDS THE
END OF THE TAF PERIOD.
VICINITY OF SFO...CURRENTLY VFR AND CALM. HIGH-END MVFR CEILING WILL
LIKELY LINGER AROUND THE TERMINAL FOR MOST OF THE MORNING WITH A
CHANCE TO LINGER THROUGH THE DAY. SOUTHERLY WINDS WILL DEVELOP THIS
MORNING, INCREASING AND BECOMING GUSTY BY THIS AFTERNOON. GUSTS IN
EXCESS OF 35 KNOTS ARE EXPECTED FROM 06Z WEDNESDAY THROUGH 00Z
THURSDAY WITH ISOLATED GUSTS UP TO 50 KNOTS POSSIBLE. RAIN
APPROACHES THE TERMINAL BY 12Z WITH RAIN SHOWERS LINGERING THROUGH
THE END OF THE TAF PERIOD.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CURRENTLY VFR WITH EASTERLY FLOW AT MRY AND
VLIFR WITH DRAINAGE FLOW AND DENSE FOG AT SNS. FOG HAS BEEN REPORTED
AT MRY THIS MORNING WITH DENSE FOG BEING REPORTED AT OTHER
TERMINALS; THUS, EVEN IF THE TERMINAL REMAINS VFR DENSE FOG IS STILL
IN THE VICINITY. VFR AND ONSHORE WINDS WILL RETURN MID-TO-LATE
MORNING WITH MVFR CEILINGS AND GUSTY DRAINAGE WINDS RETURNING
TONIGHT. RAIN SHOWERS MAY BE IN THE VICINITY TOWARDS THE VERY END OF
THE TAF PERIOD.
MARINE
(TODAY THROUGH SUNDAY)
ISSUED AT 347 AM PST TUE NOV 4 2025
WIDESPREAD HAZARDOUS CONDITIONS WILL DEVELOP THIS AFTERNOON WITH
CONDITIONS DETERIORATING OVERNIGHT. NEAR GALE TO GALE SUSTAINED
SOUTHERLY WINDS WITH SEVERE GALE TO STORM FORCE GUSTS ARE
EXPECTED, ESPECIALLY LATE TONIGHT INTO EARLY TOMORROW MORNING.
RAIN SHOWERS ARE POSSIBLE TODAY WITH THE HEAVIEST RAIN AND A
SLIGHT CHANCE FOR THUNDERSTORMS TOMORROW MORNING AND AFTERNOON.
MODERATE TO ROUGH SEAS TODAY WILL BUILD TO BECOME VERY ROUGH IN
THE INNER WATERS AND OUTER WATERS BY THURSDAY WITH CONDITIONS
SLOWLY IMPROVING FRIDAY AND INTO THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...COASTAL FLOOD ADVISORY FROM 8 AM THIS MORNING TO 2 PM PST
SATURDAY FOR CAZ006-506-508-529-530.
WIND ADVISORY FROM 10 PM THIS EVENING TO 4 PM PST WEDNESDAY FOR
CAZ006-503-504-506-508>510-512-515.
HIGH WIND WARNING FROM 10 PM THIS EVENING TO 4 PM PST WEDNESDAY
FOR CAZ502-505.
DENSE FOG ADVISORY UNTIL 8 AM PST THIS MORNING FOR CAZ516-
528>530.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PST THIS
EVENING FOR MRY BAY-PIGEON PT TO PT PINOS 0-10 NM-PIGEON PT
TO PT PINOS 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM-
SF BAY N OF BAY BRIDGE.
GALE WARNING FROM 9 PM THIS EVENING TO 3 PM PST WEDNESDAY FOR
MRY BAY-PIGEON PT TO PT PINOS 0-10 NM-PIGEON PT TO PT PINOS
10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM-SF BAY N OF
BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 3 PM PST THIS AFTERNOON FOR PT ARENA
TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 9 PM PST THIS EVENING
FOR PT ARENA TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60
NM-PT REYES TO PIGEON PT 0-10 NM.
STORM WARNING FROM 9 PM THIS EVENING TO 3 AM PST WEDNESDAY FOR
PT ARENA TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM-
PT REYES TO PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 3 PM PST THIS
AFTERNOON FOR PT REYES TO PIGEON PT 0-10 NM.
SHORT TERM...BAIN
LONG TERM....BAIN
AVIATION...SARMENT
MARINE...SARMENT
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