593
FXUS66 KMTR 041141
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
341 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
(12Z TAFS)
ISSUED AT 341 AM PST SUN JAN 4 2026
KMUX RADAR SHOWS A BAND OF RAIN OVER THE BAY AREA AND THE NORTH
CENTRAL COAST. CONDITIONS ARE A MIX OF VFR AND MVFR-IFR THE LATTER
DUE TO VISIBILITIES AND CEILINGS LOWERED IN THE RAIN. LOW PRESSURE
DEVELOPING TO THE SOUTHWEST WILL MOVE NORTHEASTWARD TODAY WITH RAIN
CHANGING OVER TO SHOWERS BY LATE AFTERNOON AND EVENING. AN ISOLATED
THUNDERSTORM OR TWO IS A POSSIBILITY TODAY DUE TO INSTABILITY. ANY
CLEARING TONIGHT AND EARLY MONDAY COUPLED TO LIGHT WINDS MAY RESULT
IN PATCHY FOG /VLIFR-IFR/.
VICINITY OF SFO...MVFR TODAY IN RAIN, RAIN CHANGING OVER TO SHOWERS
LATE TODAY AND TONIGHT. SOUTHERLY WIND 10 TO 20 KNOTS WITH A FEW
HIGHER GUSTS INTO THE 20 KNOTS RANGE POSSIBLE.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR-MVFR TODAY IN RAIN, RAIN CHANGING TO
SHOWERS LATE TODAY AND TONIGHT. SOUTHEASTERLY WINDS 5 TO 15 KNOTS.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 332 AM PST SUN JAN 4 2026
A LOW PRESSURE SYSTEM WILL RESULT IN RAIN AND A SLIGHT CHANCE OF
THUNDERSTORMS TODAY. SHOWERS CONTINUE TONIGHT AND MONDAY. BREEZY
TO GUSTY WINDS LINGER TODAY ACROSS THE WATERS, WITH HAZARDOUS
SWELLS FOR SMALLER CRAFT AT 12 TO 16 FEET THAT ABATE EARLY IN THE
WEEK. WINDS AND SEAS 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...COASTAL FLOOD ADVISORY UNTIL 3 PM PST MONDAY FOR CAZ006-506-508.
BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR CAZ006-505-509-
529-530.
COASTAL FLOOD ADVISORY UNTIL 2 PM PST THIS AFTERNOON FOR CAZ505-
509-529-530.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM PST THIS MORNING FOR MRY BAY.
SMALL CRAFT ADVISORY FROM 9 AM TO 3 PM PST MONDAY FOR MRY BAY-
PIGEON PT TO PT PINOS 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PST MONDAY FOR PIGEON PT TO PT
PINOS 0-10 NM-PT ARENA TO PT REYES 0-10 NM-PT REYES TO
PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PST MONDAY FOR 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-PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...CANEPA
MARINE...CANEPA
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