715
FXUS66 KMTR 151146
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
346 AM PST MON DEC 15 2025
..NEW SHORT TERM, LONG TERM, MARINE
KEY MESSAGES
UPDATED AT 343 AM PST MON DEC 15 2025
- DENSE FOG WILL CONTINUE TO IMPACT BAYSHORE, COASTAL, AND VALLEY
LOCATIONS THROUGH THE MORNING
- WET WEATHER RETURNS LATE TODAY AND PERSISTS THROUGH THE WEEK
AND LIKELY INTO NEXT WEEK
SHORT TERM
ISSUED AT 343 AM PST MON DEC 15 2025
(TODAY AND TONIGHT)
TODAY WILL START OFF FOGGY ONCE AGAIN FOR BAYSHORE, COASTAL, AND
VALLEY LOCATIONS. LOW VISIBILITY COULD MAKE DRIVING CONDITIONS
HAZARDOUS. IF DRIVING, SLOW DOWN, USE YOUR LOW-BEAM HEADLIGHTS, AND
LEAVE PLENTY OF DISTANCE AHEAD OF YOU. IF COMMUTING, ALLOW EXTRA
DRIVE TIME TO REACH YOUR DESTINATION SAFELY.
A CHANGE IS ON THE WAY THOUGH! IN FACT IT CAN BE SEEN IN THE FORM OF
HIGH CLOUDS STREAMING IN FROM THE WEST. THESE HIGH CLOUDS ARE
ASSOCIATED WITH A STORM FORCE LOW OFF THE COAST OF THE
OREGON/WASHINGTON BORDER THAT IS HEADED TO BRITISH COLUMBIA. THE
ACCOMPANYING COLD FRONT WILL LOSE STEAM AS IT APPROACHES THE AREA,
ALL BUT BECOMING STATIONARY. WHILE RAINFALL IS POSSIBLE AS EARLY AS
TONIGHT, IT WILL MORE THAN LIKELY HAVE TO WAIT UNTIL TOMORROW. THIS
IS WHEN SOME FORM OF UPPER-LEVEL SUPPORT (LONGWAVE TROUGH) SKIRTS
THE REGION. THE AFOREMENTIONED FEATURE WILL ACT TO SWEEP THROUGH
WHAT IS LEFT OF THE FIRST COLD FRONT BY BRINGING A GALE FORCE LOW
AND ITS ATTENDANT COLD FRONT ALONG WITH IT. RAINFALL WILL BE LIGHT
AND BENEFICIAL, GENERALLY REMAINING CONFINED NORTH OF THE GOLDEN
GATE WITH THE CENTRAL COAST REMAINING DRY OUTSIDE OF MAYBE SOME
COASTAL/HIGHER TERRAIN DRIZZLE. PROBABLY OF MORE INTEREST IS THAT
THIS PATTERN CHANGE WILL FINALLY PUT AT LEAST A TEMPORARY END TO THE
GLOOMY DAYS AS THE ATMOSPHERE BECOMES TOO TURBULENT TO SUPPORT
RADIATION FOG.
LONG TERM
ISSUED AT 343 AM PST MON DEC 15 2025
(TUESDAY THROUGH SUNDAY)
SOME LINGERING RAIN SHOWERS ARE POSSIBLE WEDNESDAY AND THURSDAY, BUT
GENERALLY SPEAKING IT WILL BE DRY. THE NEXT SYSTEM ARRIVES FRIDAY AS
A SURFACE LOW PRESSURE SYSTEM ENTERS INTO NORTHERN CALIFORNIA. THE
ATTENDANT COLD FRONT WILL BECOME A STATIONARY FRONT SATURDAY INTO
SUNDAY. THIS WILL BE THE THING TO WATCH AS STATIONARY FRONTS OFFER
AN AREA OF CONVERGENCE AND ARE A CONVEYOR BELT OF MOISTURE. STILL,
AS OF NOW, EVERYTHING THIS WEEK SEEMS BENEFICIAL, ESPECIALLY COMING
OFF OF A NOTABLE DRY SPELL FOR NOVEMBER/DECEMBER. WHEN ALL IS SAID
AND DONE, THE OFFICIAL RAINFALL TOTAL FORECAST FOR THE WEEK (MONDAY
THROUGH SUNDAY) HAS 2.50"-4.00" FOR THE HIGHER TERRAIN OF THE NORTH
BAY, 1.25"-2.50" FOR NORTH BAY INTERIOR VALLEYS, 0.50"-1.25" FOR THE
EAST BAY, SOUTH BAY, SAN FRANCISCO PENINSULA, AND CENTRAL COAST, AND
0.50" OR LESS FOR THE INTERIOR CENTRAL COAST.
THE CLIMATE PREDICTION CENTER CONTINUES TO HIGHLIGHT A MODERATE RISK
FOR PRECIPITATION MONDAY, DECEMBER 22ND THROUGH FRIDAY, DECEMBER
26TH, MODERATE RISK FOR HIGH WINDS MONDAY, DECEMBER 22ND THROUGH
SUNDAY, DECEMBER 28TH, AND A HIGH RISK FOR PRECIPITATION FOR THE
NORTH BAY MONDAY, DECEMBER 22ND THROUGH THURSDAY, DECEMBER 25TH. ALL
OF THE RAINFALL THAT WE RECEIVE THIS PRECEDING WEEK WILL
UNDOUBTEDLY PLAY A ROLE IN POTENTIAL IMPACTS NEXT WEEK.
AVIATION
(06Z TAFS)
ISSUED AT 925 PM PST SUN DEC 14 2025
PATCHY LOW CLOUDS AND FOG ARE BEGINNING TO FILL BACK IN OVER THE
REGION. LOW CIGS AND LOCALLY DENSE FOG IS EXPECTED ONCE AGAIN
TONIGHT. MODELS INDICATE CIGS WILL SCATTER OUT AROUND 17Z-19Z.
HOWEVER HIGH CLOUDS DRIFTING IN OVER THE REGION MAY HELP MIX OUT
THE BOUNDARY LAYER A BIT RESULTING IN SOME EARLIER CLEARING MONDAY
MORNING ACROSS AREA TERMINALS.
VICINITY OF SFO...VFR CONDITIONS PREVAIL CURRENTLY HOWEVER AREAS
OF PATCHY LOW CLOUDS ARE ANTICIPATED TO FILL BACK IN OVER THE BAY
TONIGHT. CONFIDENCE IS LOW AS TO THE EXTENT OF COVERAGE IMPACTING
SFO AND OAK. MODELS INDICATE CIGS MAY STAY OUT OF SFO AND OAK
HOWEVER SATELLITE IMAGERY INDICATES RAPID SPREAD CLOSE TO
THE TERMINALS AND WILL NEED TO WATCH CLOSELY.
SFO BRIDGE APPROACH...LOW CLOUDS OVER THE APPROACH EXPECTED TO
FILL IN OVERNIGHT WITH LOCALLY DENSE FOG.
MONTEREY BAY TERMINALS...IFR CIGS WILL PREVAIL THROUGH TONIGHT
WITH CLEARING ANTICIPATED AFTER 17Z MONDAY MORNING.
MARINE
(TODAY THROUGH SATURDAY)
ISSUED AT 343 AM PST MON DEC 15 2025
SOUTHERLY FLOW WILL PREVAIL NORTH OF PIGEON POINT AHEAD OF AN
APPROACHING FRONTAL SYSTEM. CONDITIONS ARE IDEAL FOR DENSE FOG
ACROSS THE BAYS AND CLEARING MAY BE SLOW TODAY FROM THE SAN
FRANCISCO BAY TO THE WEST DELTA. MAINLY LIGHT WINDS WILL PREVAIL
ACROSS THE COASTAL WATERS EXCEPT NORTHWESTERLY WINDS BECOMING
GUSTY ACROSS THE SOUTHERN COASTAL WATERS TODAY TO TUESDAY. WINDS
WILL BECOME GUSTY WITH INCREASING RAIN CHANCES OVER THE NORTHERN
WATERS MID-WEEK. LIGHT SEAS WILL GRADUALLY BUILD BECOMING
MODERATE TO ROUGH BY MID WEEK.
MTR WATCHES/WARNINGS/ADVISORIES
CA...DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR CAZ506-508-
510-513-516-528>530.
PZ...DENSE FOG ADVISORY UNTIL 11 AM PST THIS MORNING FOR MRY BAY-SF
BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 PM PST
TUESDAY FOR PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...SARMENT
LONG TERM....SARMENT
AVIATION...CW
MARINE...CANEPA
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