622
FXUS66 KMTR 301737
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1037 AM PDT THU OCT 30 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 303 AM PDT THU OCT 30 2025
- PLEASANT WEATHER AND SLIGHTLY ABOVE NORMAL TEMPERATURES
CONTINUE THROUGH THIS WEEKEND
- COOLING TREND BEGINS MONDAY WITH SEASONAL TEMPERATURES
RETURNING
- UNSETTLED WEATHER RETURNS EARLY TO MID NEXT WEEK WITH RAIN
LIKELY ACROSS THE BAY AREA AND CENTRAL COAST
UPDATE
ISSUED AT 839 AM PDT THU OCT 30 2025
SATELLITE IMAGERY SHOWS STRATUS FILLING THE NORTH BAY VALLEYS,
MUCH OF THE BAY AREA TO THE WEST OF THE BERKELEY HILLS, THE SOUTH
BAY, AND THE SOUTHERN MONTEREY BAY REGION, WITH PATCHY DENSE FOG
OBSERVED ACROSS THE NORTH BAY VALLEYS AND NEAR SALINAS. DRIVERS
WHO ENCOUNTER DENSE FOG SHOULD SLOW DOWN, USE LOW-BEAM
HEADLIGHTS, AND ALLOW EXTRA SPACE BETWEEN THEM AND THE CAR IN
FRONT. THE LAST FEW SATELLITE FRAMES HAVE SHOWN THE STRATUS DECK
CONTINUING TO EXPAND, BUT IT IS EXPECTED TO DISSIPATE AS THE SUN
CONTINUES TO RISE AND WARM THE REGION. BEYOND THE MORNING, SOME
MID- TO HIGH-LEVEL CLOUDS ARE POSSIBLE ACROSS THE BAY AREA THIS
AFTERNOON.
DIALH
SHORT TERM
ISSUED AT 303 AM PDT THU OCT 30 2025
(TODAY AND TONIGHT)
BIT OF A CHANGE COMPARED TO THE LAST TWO NIGHTS FOR ANY NIGHT OWLS,
THE APPROACHING SHORTWAVE TROUGH IS ALLOWING THE MARINE LAYER TO
DEEPEN WITH WIDESPREAD STRATUS DEVELOPING OVER THE MARINE
ENVIRONMENT. STRATUS AND FOG ARE POSSIBLE ALONG THE COASTLINE AND
ACROSS THE NORTH BAY INTERIOR VALLEYS THIS MORNING. A DRY COLD FRONT
WILL PASS THROUGH THE BAY AREA TODAY AND BRING COOLER, MORE SEASONAL
TEMPERATURES TO THE REGION. THIS WILL BE A FAIRLY NOTICEABLE
DIFFERENCE WITH HIGH TEMPERATURES RUNNING ANYWHERE BETWEEN 5 TO 10
DEGREES COOLER TODAY THAN YESTERDAY. INTERIOR HIGH TEMPERATURES WILL
BE IN THE LOW TO MID 70S, UPPER 60S TO LOW 70S ALONG THE BAY
SHORELINE, AND IN THE UPPER 50S TO 60S ALONG THE COASTLINE.
TEMPERATURES WILL REMAIN WARMER ACROSS THE INTERIOR CENTRAL COAST
WHERE HIGHS WILL BE IN THE LOW TO MID 80S. LIGHT OFFSHORE FLOW
CONTINUES ACROSS THE INTERIOR MOUNTAIN RANGES WITH WINDS TO BECOME
ONSHORE BY THIS AFTERNOON. WINDS STRENGTHEN ACROSS THE MARINE
ENVIRONMENT TODAY WITH BREEZY AFTERNOON WINDS ALONG THE COASTLINE
AND WITHIN VALLEYS.
LONG TERM
ISSUED AT 303 AM PDT THU OCT 30 2025
(FRIDAY THROUGH WEDNESDAY)
UPPER LEVEL RIDGING AND HIGH PRESSURE RETURN FRIDAY AND BRING WARMER
TEMPERATURES BACK TO THE BAY AREA. HIGH TEMPERATURES WILL BE IN THE
MID 70S TO LOW 80S ACROSS THE INTERIOR WHILE COASTAL AREAS STAY IN
THE UPPER 50S TO MID 60S. TEMPERATURES COOL SLIGHTLY MONDAY AS THE
CENTER OF THE UPPER LEVEL RIDGE PROGRESSES EASTWARD AND AN UPPER
LEVEL TROUGH APPROACHES FROM THE WEST. HIGH TEMPERATURES ACROSS THE
INTERIOR ON MONDAY WILL GENERALLY BE IN THE 70S WHILE COASTAL AREAS
STAY IN THE 60S. TEMPERATURES DROP MORE NOTICEABLY, AS THE TROUGH
ARRIVES, TUESDAY AND WEDNESDAY WITH INTERIOR HIGH TEMPERATURES
DROPPING INTO THE 60S TO LOW 70S AND COASTAL AREAS IN THE UPPER 50S
TO 60S. GIVEN THE PLEASANT FALL WEEKEND ON TAP, IT WOULD BE A GOOD
TIME TO MAKE SURE ANY OUTDOORS ITEMS ARE SECURED AND GUTTERS ARE
CLEAR AHEAD OF NEXT WEEKS POTENTIAL RAIN EVENT.
THERE IS STILL A FAIR AMOUNT OF UNCERTAINTY REGARDING OUR INCOMING
SYSTEM. FIRST OFF, GUIDANCE HAS REMAINED CONSISTENT IN SHOWING A
DEEP UPPER LEVEL TROUGH EXTENDING INTO THE BAY AREA AND CENTRAL
COAST ARRIVING NEXT WEEK. HOWEVER, GUIDANCE HAS PUSHED BACK THE
ARRIVAL OF THE TROUGH FROM MONDAY/TUESDAY TO TUESDAY/WEDNESDAY. THIS
MAKES MONDAY MORE OF A TRANSITION DAY FROM UPPER LEVEL RIDGING TO
UPPER LEVEL TROUGHING RATHER THAN THE FIRST DAY OF OUR NEXT SYSTEM.
ENSEMBLE MEMBERS ARE LEANING TOWARDS THE BULK OF THIS SYSTEM TAKING
PLACE WEDNESDAY/THURSDAY SO WE MAY SEE FURTHER ADJUSTMENTS TO THE
TIMING OF THIS SYSTEM AS IT GETS CLOSER. BOTH THE ECMWF AND GFS ARE
COMING ON BOARD THAT THE BAY AREA AND CENTRAL COAST WILL SEE
PRECIPITATION EARLY TO MID NEXT WEEK BUT UNCERTAINTY REMAINS AS TO
HOW MUCH WE WILL SEE. ENSEMBLE GUIDANCE CONTINUES TO SHOW A SPLIT
BETWEEN "BOOM" (MODERATE AMOUNT OF RAIN) VS "BUST" (LITTLE RAIN)
SCENARIOS. FOR EXAMPLE, USING THE 00Z 30TH OCTOBER GFS RUN, OUT OF
30 ENSEMBLE MEMBERS 14 MEMBERS SHOW THE SANTA ROSA AIRPORT RECEIVING
GREATER THAN 1 INCH OF RAIN IN 24 HOURS WHILE 16 SHOW IT RECEIVING
LESS THAN AN INCH OF RAIN IN 24 HOURS. ENSEMBLE GUIDANCE FROM THE
ECMWF SHOWS A SIMILAR SPLIT BETWEEN MEMBERS SHOWING HIGHER
PRECIPITATION TOTALS VS LOWER PRECIPITATION TOTALS. WE WILL START
TO SEE A BETTER CONSENSUS ON PRECIPITATION TOTALS AS THIS SYSTEM
APPROACHES AND THE TIMING/TRACK OF THE SYSTEM COME INTO BETTER
FOCUS. WINDS LOOK TO STRENGTHEN AROUND THE TIME OF FRONTAL
PASSAGE BUT CURRENTLY STAY BELOW WIND ADVISORY CRITERIA. SPECIFICS
RELATING TO THIS SYSTEM ARE LIKELY TO CONTINUE EVOLVING AS IT
GETS CLOSER IN TIME SO RESIDENTS ARE ADVISED TO STAY UP TO DATE
WITH THE FORECAST AS WE HEAD INTO NEXT WEEK.
AVIATION
(18Z TAFS)
ISSUED AT 1037 AM PDT THU OCT 30 2025
SATELLITE SHOWS AREAS OF STRATUS AND FOG /IFR-LIFR/ OTHERWISE IT'S
VFR WITH STEADY MIXING OCCURRING THROUGH LATE MORNING AND AFTERNOON.
STRATUS AND FOG /IFR-LIFR/ RETURN THIS EVENING AND OVERNIGHT INTO
FRIDAY MORNING.
VICINITY OF SFO...IFR UNTIL 20Z THEN VFR THROUGH THE AFTERNOON AND
EVENING. IFR DUE TO STRATUS RETURNS 12Z FRIDAY MORNING, MIXING OUT
21Z FRIDAY. WESTERLY WIND NEAR 12 KNOTS INCREASING TO 15 TO 20 KNOTS
THIS AFTERNOON AND EVENING. WIND DECREASING TONIGHT AND BECOMING LIGHT
AND VARIABLE FRIDAY MORNING THEN WESTERLY 10 KNOTS FRIDAY AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR STEADILY MIXING OUT EXCEPT LINGERING
VICINITY KMRY INTO THE AFTERNOON. STRATUS AND FOG /IFR-LIFR/ RETURN
THIS EVENING, OVERNIGHT AND FRIDAY MORNING. ONSHORE WINDS 5 TO 10
KNOTS DURING THE AFTERNOON AND EARLY EVENING BECOMING LIGHT EAST TO
SOUTHEAST TONIGHT AND FRIDAY MORNING.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 839 AM PDT THU OCT 30 2025
EXPECT MODERATE TO FRESH BREEZES WITH OCCASIONAL NEAR GALE FORCE
WINDS OVER THE OUTER WATERS AND NEARSHORE SOUTH OF POINT SUR
THROUGH THE WEEKEND. SEAS BUILD TODAY BUT SUBSIDE SLIGHTLY ON
FRIDAY THEN REBUILD AGAIN OVER THE WEEKEND WITH A LONGER PERIOD
SWELL. WINDS REDUCE INTO THE EARLY WORK WEEK BUT BUILD AGAIN IN
THE MID WEEK AHEAD OF FRONTAL PASSAGES AND RAIN CHANCES.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT FRIDAY
FOR MRY BAY.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PIGEON PT TO PT
PINOS 0-10 NM-PT ARENA TO PT REYES 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM FRIDAY TO 3 AM PDT SATURDAY FOR
PIGEON PT TO PT PINOS 0-10 NM-PT ARENA TO PT REYES 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR PT REYES TO PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT FRIDAY FOR PT ARENA TO PT
REYES 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PIGEON PT TO PT
PINOS 10-60 NM.
SHORT TERM...KENNEDY
LONG TERM....KENNEDY
AVIATION...CANEPA
MARINE...CANEPA
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