575
FXUS66 KMTR 161114
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
414 AM PDT TUE SEP 16 2025
..NEW SHORT TERM, LONG TERM, MARINE
KEY MESSAGES
UPDATED AT 412 AM PDT TUE SEP 16 2025
- DENSE FOG ADVISORY FOR PORTIONS OF THE CENTRAL COAST UNTIL 10AM
- ABOVE NORMAL TEMPERATURES WITH MODERATE HEATRISK PERSISTS TODAY
AND WEDNESDAY
- ISOLATED TO SCATTERED THUNDERSTORMS POSSIBLE THURSDAY INTO
EARLY FRIDAY
SHORT TERM
ISSUED AT 412 AM PDT TUE SEP 16 2025
(TODAY AND TONIGHT)
AREAS OF DENSE FOG HAVE DEVELOPED OVERNIGHT FROM THE SAN FRANCISCO
PENINSULA COAST SOUTH THROUGH SANTA CRUZ, MONTEREY BAY, THE SALINAS
VALLEY AND THE BIG SUR COASTLINE, WITH A DENSE FOG ADVISORY OUT
UNTIL 10AM. OTHERWISE WE'RE LOOKING AT ANOTHER DAY WITH TEMPERATURES
WELL ABOVE NORMAL AND WIDESPREAD MODERATE HEATRISK, EXPECT DAYTIME
HIGHS TODAY TO BE SLIGHTLY HIGHER THAN YESTERDAY. REMEMBER TO REMAIN
HYDRATED WITH PLENTY OF WATER AND ELECTROLYTES, LIMIT TIME OUTDOORS
DURING PEAK HEATING IF POSSIBLE, AND NEVER LEAVE CHILDREN OR PETS
UNATTENDED IN VEHICLES.
KEEPING WITH THE WARM TREND, OVERNIGHT LOWS INTO WEDNESDAY MORNING
WILL CONTINUE TO BE ABOVE NORMAL AS WELL, WITH SOME ELEVATED AREAS
IN THE BAY AREA, EAST BAY HILLS, DIABLO RANGE, AND SANTA LUCIAS
REMAINING IN THE 70S WITH POOR RH RECOVERY.
LONG TERM
ISSUED AT 412 AM PDT TUE SEP 16 2025
(WEDNESDAY THROUGH MONDAY)
WEDNESDAY WILL BE THE LAST DAY OF THE THREE DAY HEAT WAVE, WITH
TEMPERATURES SIMILAR TO TODAYS HIGHS AND WIDESPREAD MODERATE
HEATRISK. A PATTERN SHIFT FOR THURSDAY AND FRIDAY INTO THE WEEKEND
WILL CONTINUE TO BRING COOLER TEMPERATURES, RAINFALL CHANCES AND
ELEVATED THUNDERSTORM CHANCES. HOWEVER, THERE HAS BEEN A NOT SO
SUBTLE SHIFT IN GUIDANCE ACROSS THE BOARD IN THE MOST RECENT
UPDATES. ISOLATED TO SCATTERED THUNDERSTORMS REMAIN IN THE FORECAST
FOR NOW FROM THE BAY AREA SOUTH THROUGH THE CENTRAL COAST DURING THE
DAY THURSDAY INTO EARLY FRIDAY. THE UPPER LEVEL PATTERN HAS SHIFTED
QUITE A BIT FROM MONDAY AFTERNOONS FORECAST UPDATE TO THIS MORNING.
AN UNUSUAL SYNOPTIC PATTERN (A DOUBLE OMEGA BLOCK ACROSS CONUS?),
AGREED UPON IN NUMEROUS FORMS OF DETERMINISTIC GUIDANCE HAS THE
REMNANTS OF MARIO BECOMING THE MORE DOMINANT FEATURE AS IT LIFTS
NORTH INTO SOCAL. AS A RESULT, THE BULK OF RAINFALL AND
INSTABILITY HAS TAKEN A NOTABLE SHIFT EAST AND SOUTH AWAY FROM OUR
FORECAST AREA. THAT DOESN'T MEAN WE WON'T SEE ANY SHOWERS OR
THUNDERSTORMS OVER THE NEXT 72 HOURS, BUT CONFIDENCE IS LOWER THAN
IT WAS YESTERDAY AND THE TREND APPEARS TO BE DRIER. THERE IS TIME
FOR THE FORECAST TO WHIPLASH BACK TO WETTER AND MORE UNSTABLE FOR
OUR AREA, ESPECIALLY ACROSS THE CENTRAL COAST. BUT FOR NOW
(INCLUDING MOST RECENT 06Z GFS UPDATE, AND SLOWER NORTHERLY
PROGRESSION OF 06Z HRRR), IT APPEARS THAT MARIO GETS ABSORBED
INLAND ACROSS SOCAL UNDER THE NEGATIVELY TILTED RIDGE AXIS FROM SE
OREGON TO SOUTHERN ARIZONA. PWATS WILL STILL BE WELL ABOVE NORMAL
AND EVEN IF WE DON'T SEE ANY RAINFALL IT WILL FEEL MUGGY. WE
OFTEN SAY 'CHECK BACK FOR UPDATES', TODAY IS DEFINITELY ONE OF
THOSE DAYS.
AVIATION
(06Z TAFS)
ISSUED AT 1017 PM PDT MON SEP 15 2025
WINDS ARE REDUCING, AND IFR/LIFR CIGS BUILD ALONG THE COAST,
AFFECTING HAF AND THE MONTEREY BAY TERMINALS. FOG IS EXPECTED IN
THOSE AREAS FURTHER INTO THE NIGHT AND INTO THE MORNING. MOMENTS OF
IFR CIGS LOOK TO AFFECT OAK INTO TUESDAY MORNING, BUT DON'T FILL
OVER THE SITE CONSISTENTLY. CLOUD COVER RETREATS INTO THE LATE
MORNING ON TUESDAY CLEARING FOR ALL BUT HAF WHICH SEES LIFR CIGS
TURN TO IFR LEVELS THAT AFTERNOON THEN A BRIEF PERIOD OF SCATTERING.
MODERATE TO BREEZY WINDS ARRIVE TUESDAY AFTERNOON AND LOOK TO LINGER
INTO THAT EVENING. LIFR CIGS RETURN TO HAF TUESDAY EVENING AS WINDS
REDUCE.
VICINITY OF SFO...VFR THROUGH THE TAF PERIOD. WINDS ARE REDUCING AND
WILL BECOME LIGHT AND VARIABLE THROUGH THE NIGHT AND TUESDAY
MORNING. MODERATE NORTHWEST BUILD INTO TUESDAY AFTERNOON, BUT REDUCE
INTO THAT NIGHT.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR/LIFR CIGS ARE BUILDING AROUND THE THE
BAY AS WINDS BECOME LIGHT. CIGS LOWER AND FOG BUILDS AROUND THE
MONTEREY BAY INTO THE LATE NIGHT. SNS CLEARS INTO THE MID MORNING,
WHILE MRY SEES SOME IMPROVEMENTS IN VISIBILITIES, BUT HOLDS LIFR
CIGS UNTIL CLEARING IN THE LATE MORNING. EXPECT VFR AND MODERATE
WEST WINDS FOR TUESDAY AFTERNOON. WINDS REDUCE THAT EVENING AND INTO
THE NIGHT WITH CIGS RETURNING BEYOND THE TAF PERIOD.
MARINE
(TODAY THROUGH SUNDAY)
ISSUED AT 412 AM PDT TUE SEP 16 2025
A GENTLE TO MODERATE NORTHERLY BREEZE WILL PREVAIL TODAY,
INCREASING TO BECOME FRESH TO STRONG FOR THE NORTHERN OUTER WATERS
WEDNESDAY AND THURSDAY. MODERATE SEAS WILL PREVAIL TODAY,
BUILDING TO BECOME ROUGH FOR THE OUTER WATERS WEDNESDAY THROUGH
FRIDAY. ISOLATED THUNDERSTORMS ARE POSSIBLE WEDNESDAY AND
THURSDAY WITH ISOLATED RAIN SHOWERS LINGERING THROUGH SATURDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR CAZ509-
528>530.
PZ...DENSE FOG ADVISORY UNTIL 10 AM PDT THIS MORNING FOR MRY BAY.
SHORT TERM...JM
LONG TERM....JM
AVIATION...MURDOCK
MARINE...SARMENT
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