657
FXUS66 KMTR 041801
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1001 AM PST SUN JAN 4 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 117 PM PST SAT JAN 3 2026
- ONE LAST DAY OF COASTAL FLOODING FROM KING TIDES
- CHANCE OF THUNDERSTORMS TODAY
- HAZARDOUS BEACH CONDITIONS THROUGH TONIGHT
- DAILY RAIN SHOWERS EXPECTED THROUGH MONDAY
SHORT TERM
ISSUED AT 1202 AM PST SUN JAN 4 2026
(TODAY AND TONIGHT)
THE UNSETTLED WEATHER CONTINUES AS ANOTHER COLD FRONT APPROACHES
THE COAST OVER THE NEXT 12 HOURS. SCATTERED SHOWERS ARE BECOMING
MORE ORGANIZED AND NUMEROUS THROUGH THE MORNING. THERE HAVE BEEN A
FEW LIGHTNING STRIKES OVER THE COASTAL WATERS IN THE LAST 30
MINUTES, AND THE ENVIRONMENT LOOKS ABLE TO SUPPORT THIS CONVECTION
OVER THE BAY AREA THROUGH THE EARLY MORNING. THE HEAVIER BAND OF
RAIN WILL GRADUALLY SLIDE SOUTH OVER THE NEXT FEW HOURS, FOCUSING
IMPACTS ON SAN MATEO AND SANTA CRUZ THROUGH MIDDAY. HEAVIER
SHOWERS WILL LIKELY LEAD TO NUISANCE FLOODING AND POSSIBLE
LANDSLIDES. IF THE THUNDERSTORMS MAKE IT TO LAND, IT'S UNLIKELY
THEY WILL PRODUCE SEVERE WIND GUSTS OR TORNADOES. THERE IS STILL
SEVERAL HUNDRED J/KG OF CAPE, BUT THE LOW LEVEL SHEAR HAS
DECREASED BELOW 10 KTS, TOO WEAK TO SUPPORT TORNADOGENESIS. GARDEN
VARIETY THUNDERSTORMS STILL BRING HAZARDS, NAMELY LIGHTING
STRIKES, HEAVY DOWNPOURS AND SMALL HAIL. SHOWER ACTIVITY WILL
GRADUALLY DECREASE THROUGH THE EVENING BEFORE THE NEXT ROUND ON
MONDAY.
LONG TERM
ISSUED AT 1202 AM PST SUN JAN 4 2026
(MONDAY THROUGH SATURDAY)
HIGH RESOLUTION MODELS ARE SHOWING A BRIEF BREAK IN THE RAIN
BETWEEN SUNDAY EVENING AND EARLY MONDAY MORNING AS A DRY SLOT
MOVES THROUGH AFTER FRONTAL PASSAGE. THE MOISTURE WILL QUICKLY
RECHARGE AS A LOW PRESSURE SYSTEM MOVES NEAR THE COAST. THIS
SYSTEM WILL FLIP THE DRY POST-FRONTAL NW WINDS TO MOIST SW'RLY
FLOW. MONDAY WILL BE ANOTHER WET ONE. EVERYONE SHOULD PICK UP
ANOTHER 1-2" FROM NOW UNTIL TUESDAY MORNING. AT THAT POINT THE LOW
WILL WEAKEN IN PLACE. THERE'S A LOT OF UNCERTAINTY REGARDING
TUESDAY. SINCE THE LOW ISN'T REALLY MOVING, IT'S HARD TO PIN DOWN
EXACTLY WHAT WILL HAPPEN TO THE ASSOCIATED MOISTURE. OUR OFFICIAL
QPF FORECAST DRIES OUT STARTING TUESDAY, BUT THERE'S STILL A
DECENT PROBABILITY OF PRECIPITATION THROUGH EVEN WEDNESDAY. BY
THURSDAY HIGH PRESSURE WILL CONFIDENTLY MOVE IN, SHUTTING DOWN
RAIN CHANCES AND CLEARING UP THE WEATHER FOR THE WEEKEND. LOW
TEMPERATURES WILL RESPOND TO THE CLEARING SKIES THANKS TO ENHANCED
RADIATIONAL COOLING AT NIGHT. MANY INLAND AREAS WILL BE DROPPING
BACK INTO THE 30S STARTING THURSDAY MORNING AND WE SHOULD SEE SOME
FROST FRIDAY. AS A HIGH AMPLITUDE RIDGE BUILDS, THE DRY WEATHER
LOOKS TO SETTLE IN PLACE, WITH NO SIGNIFICANT CHANCE OF RAIN
THROUGH THE END OF NEXT WEEK.
AVIATION
(18Z TAFS)
ISSUED AT 1001 AM PST SUN JAN 4 2026
SHOWERS ARE CONTINUING TO MOVE ACROSS THE BAY AREA AND CENTRAL COAST
WITH LARGELY MVFR CONDITIONS EXPECTED. RAIN RATES ARE LIGHT TO
MODERATE WITH LOCALIZED SHORT PERIODS OF HEAVY RAIN. WINDS ARE
BREEZY BUT NOT AS GUSTY AS YESTERDAY WITH PEAK WINDS AROUND 15 KNOTS
THROUGH THIS AFTERNOON. EXPECTED CIG HEIGHTS TO RISE BY LATE
AFTERNOON/EARLY EVENING BEFORE LOWERING AGAIN OVERNIGHT AS ANOTHER
ROUND OF RAIN AIMS AT THE BAY AREA AND CENTRAL COAST. EXPECT
VISIBILITIES AND CEILINGS TO DROP BELOW WHAT IS LISTED IN THE TAF IF
A PARTICULARLY STRONG SHOWER MOVES OVER THE AIRPORT.
VICINITY OF SFO...BREEZY SOUTHERLY TO SOUTHWESTERLY WINDS CONTINUE
THROUGH THE TAF PERIOD. SHOWERS WILL BECOME MORE SCATTERED IN NATURE
BY THIS AFTERNOON AS THE MAIN RAIN BAND MOVES FURTHER SOUTH. A
SECOND ROUND OF LIGHT TO MODERATE RAIN ARRIVES TONIGHT WITH
CONDITIONS STAYING ON THE BORDER OF MVFR-VFR. EXPECT TEMPORARY DROPS
IN VISIBILITY AND CEILING HEIGHTS IF A STRONGER SHOWER MOVES OVER
SFO.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...MVFR. THE MAIN RAIN BAND IS TRAINING OVER
THE MONTEREY PENINSULA WITH MODERATE TO AT TIMES HEAVY RAIN
CONTINUING THROUGH THIS AFTERNOON. SHOWERS BECOME MORE SCATTERED
THIS EVENING BEFORE ANOTHER ROUND OF LIGHT TO MODERATE RAIN RETURNS
OVERNIGHT. CONFIDENCE IS LOW TO MODERATE THAT MVFR CIGS WILL RISE
ABOVE 3000 FT LATE TONIGHT. IT IS POSSIBLE AS THE SECOND RAIN BAND
REACHES MRY AND SNS AROUND 14/15Z THAT CIGS WILL LOWER BELOW 3000 FT
AGAIN.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 1001 AM PST SUN JAN 4 2026
RAIN AND A SLIGHT CHANCE OF THUNDERSTORMS CONTINUE TODAY WITH
SHOWERS EXPECTED TO CONTINUE THROUGH MONDAY. WINDS REMAIN BREEZY
THROUGH THIS EVENING BEFORE STRENGTHENING OVERNIGHT. HAZARDOUS
SEAS BETWEEN 12 TO 16 FEET CONTINUE FOR SMALLER CRAFT BEFORE WINDS
AND SEAS DIMINISH EARLY NEXT WEEK. WINDS AND SEAS ARE EXPECTED TO
BUILD AGAIN DURING THE LATE WEEK.
BEACHES
ISSUED AT 117 PM PST SAT JAN 3 2026
A COASTAL FLOOD ADVISORY IS IN EFFECT FOR THE SAN FRANCISCO BAY,
SAN PABLO BAY, PACIFIC COAST, AND MONTEREY BAY THROUGH 2 PM SUNDAY
DUE TO PERIGEAN SPRING TIDES (KING TIDES) AND UP TO 1 FOOT OF
STORM SURGE. THE COMBINATION OF THESE FACTORS WILL BRING MINOR TO
MODERATE COASTAL FLOODING TO THE LOW-LYING AREAS NEAR SHORELINES
AND TIDAL WATERWAYS DURING HIGH TIDE LATE SUNDAY MORNING.
HIGH TIDE IS EXPECTED TO BE 1.9 FT ABOVE NORMAL AT 11:18 AM
SUNDAY. THESE PREDICTIONS INCLUDE UP TO 1 FOOT OF STORM SURGE THAT
WILL ENHANCE THE ASTRONOMICAL TIDE AND FLOODING THREAT. HIGH TIDE
VARIES UP TO 90 MINUTES EARLIER OR LATER ALONG THE PACIFIC COAST
AND THROUGH THE SAN FRANCISCO BAY, RESPECTIVELY.
A BEACH HAZARD STATEMENT IS IN EFFECT SUNDAY THROUGH 10 PM. LARGE
SWELL WILL IMPACT THE PACIFIC BEACHES, GENERATING LARGE BREAKING
WAVES UP TO 20 FEET, STRONG RIP CURRENTS, AND SNEAKER WAVES.
INEXPERIENCED SWIMMERS SHOULD AVOID THE WATER. NOBODY SHOULD CLIMB
THE COASTAL ROCKS. NEVER TURN YOUR BACK ON THE OCEAN.
MTR WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT UNTIL 10 PM PST THIS EVENING FOR CAZ006-
505-509-529-530.
COASTAL FLOOD ADVISORY UNTIL 3 PM PST MONDAY FOR CAZ006-506-508.
COASTAL FLOOD ADVISORY UNTIL 2 PM PST THIS AFTERNOON FOR CAZ505-
509-529-530.
PZ...SMALL CRAFT ADVISORY FROM 3 AM TO 9 PM PST MONDAY FOR MRY BAY.
SMALL CRAFT ADVISORY UNTIL 3 PM PST MONDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT REYES TO PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PST MONDAY FOR PIGEON PT TO PT
PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PST MONDAY FOR PT ARENA TO PT
REYES 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
GALE WARNING FROM 9 AM TO 3 PM PST MONDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PST THIS EVENING FOR PIGEON PT
TO PT PINOS 10-60 NM.
SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PST MONDAY FOR PIGEON PT
TO PT PINOS 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...KENNEDY
MARINE...KENNEDY
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