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FXUS66 KMTR 021753
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
953 AM PST FRI JAN 2 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1236 AM PST FRI JAN 2 2026
- HIGH ASTRONOMICAL TIDES COMBINED WITH STORM SURGE WILL BRING
SUBSTANTIAL TIDAL FLOODING THROUGH SUNDAY
- STRONG SOUTHERLY WINDS FRIDAY NIGHT INTO SATURDAY MORNING
- CHANCE OF THUNDERSTORMS FRIDAY NIGHT THROUGH THE WEEKEND
- DAILY RAIN SHOWERS EXPECTED THROUGH MONDAY
UPDATE
ISSUED AT 904 AM PST FRI JAN 2 2026
IT HAS BEEN FAIRLY QUITE OVERNIGHT INTO THIS MORNING WITH RAIN
MOSTLY CONFINED TO THE COASTAL TERRAIN AND THE NORTH BAY. RAINFALL
AMOUNTS IN THE PAST 6 HOURS HAVE BEEN UP TO 0.15" IN THE
AFOREMENTIONED AREAS. THE ONGOING FORECAST REMAINS ON TRACK WITH NO
UPDATES ANTICIPATED THIS MORNING. OUR NEXT STORM SYSTEM IS STILL ON
TRACK TO ARRIVE LATE THIS EVENING AND CONTINUE INTO EARLY SATURDAY
MORNING WITH SOUTHERLY WINDS INCREASING BY THIS AFTERNOON. GUSTS UP
TO 50 MPH WILL BE LIKELY ALONG THE COAST AND IN THE HIGHER TERRAIN
ACROSS THE REGION WHERE A WIND ADVISORY REMAINS IN EFFECT FROM 1 PM
FRIDAY TO 1 PM SATURDAY. ALSO, RAIN WILL INCREASE IN INTENSITY LATE
TONIGHT AND INTO SATURDAY MORNING.
RGASS
SHORT TERM
ISSUED AT 1236 AM PST FRI JAN 2 2026
(TODAY AND TONIGHT)
THERE'S A FEW SCATTERED SHOWERS ON RADAR, BUT WE'RE MOSTLY
ENJOYING A BREAK BEFORE THE NEXT ROUND OF HEAVY RAIN AND STRONG
WIND ARRIVES TONIGHT. SOUTHERLY WINDS ARE STARTING TO SHOW UP
ALONG THE COAST AND IN PROPERLY ORIENTED VALLEYS. SALINAS AND HALF
MOON BAY ARE BOTH REPORTING A MODERATE SOUTHERLY BREEZE WITH
GUSTS UP TO 20 KNOTS. THE IR SATELLITE IMAGE SHOWS WHAT WE'RE UP
AGAINST LATER TODAY. A MATURE LOW PRESSURE SYSTEM IN THE EASTERN
PACIFIC AROUND 40N137W IS SUPPORTING A VERY LONG COLD-TYPE
OCCLUDED FRONT. AS THIS FRONT APPROACHES THE COAST OVERNIGHT, THE
RAIN INTENSITY AND WIND STRENGTH WILL BOTH INCREASE. WINDS WILL
STEADILY INCREASE THROUGH THE DAY, PEAKING AROUND MIDNIGHT.
SUSTAINED WINDS OF 15-25 MPH ARE EXPECTED, WITH OCCASIONAL GUSTS
TO 50 MPH ALONG THE COAST AND IN HIGHER TERRAIN. THAT'S A LITTLE
WEAKER THAN LAST WEEK'S STORMS, BUT STILL ENOUGH TO CAUSE TREE
DAMAGE AND POSSIBLE POWER OUTAGES. ON AVERAGE WE'RE EXPECTING
ABOUT 1/2" OF RAIN OVERNIGHT, WITH UP TO 3" IN THE COASTAL
MOUNTAINS AND CLOSER TO 1/4" IN THE RAIN SHADOWED VALLEYS.
LONG TERM
ISSUED AT 1236 AM PST FRI JAN 2 2026
(SATURDAY THROUGH THURSDAY)
AFTER THE FRONT PASSES SATURDAY MORNING, THE PRECIPITATION MODE
WILL SWITCH FROM STRATIFORM RAIN TO CONVECTIVE SHOWERS. SOME OF
THESE SHOWERS WILL BE STRONG, AND THERE IS A DECENT CHANCE FOR
THUNDERSTORMS THROUGHOUT THE DAY SATURDAY AS A FEW POST FRONTAL
SHORT WAVE TROUGHS MOVE THROUGH. THE 06Z HRRR SHOWS ONE OF THESE
PULSES WILL LINE UP WELL WITH THE WARMER, MORE UNSTABLE CONDITIONS
IN THE AFTERNOON. THERE IS A MARGINAL CHANCE FOR SEVERE
THUNDERSTORMS IN THE NORTH AND EAST BAY, WITH TORNADOES AS THE
MOST LIKELY SEVERE THREAT IN THE TYPICAL LOW CAPE, HIGH SHEAR
ENVIRONMENT. HIGH RESOLUTION MODEL POINT SOUNDINGS IN THE NORTH
BAY SHOW AROUND 100 J/KG OF CAPE, WITH 40-50 KTS OF 0-1KM SHEAR,
LOW LCL HEIGHTS, AND A NICELY CURVED LOW LEVEL HODOGRAPH SATURDAY
AFTERNOON. THE SEVERE THREAT IS FOCUSED ON THE NORTH BAY, BUT NOT
CONFINED THERE. LANDFALLING WATERSPOUTS ARE POSSIBLE ALONG THE
COAST.
REINFORCING WET COLD FRONTS WILL MOVE THROUGH SUNDAY AND MONDAY,
WITH A MUCH DRIER FROPA MIDWEEK. THIS PARADE OF COLD FRONTS WILL
DROP THE 1000-500 MB THICKNESS FROM 5,530 M TODAY TO 5,340 M BY
FRIDAY, BRINGING SNOW LEVELS TO AROUND 3,000 FEET. IF WE CAN GET
ANY MOISTURE LATE NEXT WEEK WE'D HAVE A REAL CHANCE FOR SOME SNOW
FLAKES IN THE HIGHER PEAKS AROUND THE BAY AREA AND CENTRAL COAST.
OTHERWISE WE'LL SEE TEMPERATURES DROP BACK INTO THE 30S FOR
INLAND AREAS TOWARDS THE END OF NEXT WEEK AS A DRIER, MORE STABLE
PATTERN MOVES IN.
AVIATION
(18Z TAFS)
ISSUED AT 952 AM PST FRI JAN 2 2026
CURRENTLY VFR BUT EXPECT UNSETTLED WEATHER TO DEVELOP THROUGHOUT THE
DAY WITH AN ATMOSPHERIC RIVER ARRIVING TONIGHT. WINDS STRENGTHEN
LATE THIS MORNING/EARLY THIS AFTERNOON WITH GUSTS PEAKING BETWEEN 30
TO 35 KNOTS TONIGHT. LOCALLY HIGHER GUSTS TO AROUND 40 KNOTS ARE
EXPECTED ALONG THE COASTLINE AND WITHIN VALLEYS. RAIN CHANCES
INCREASE THIS EVENING INTO TOMORROW MORNING WITH MODERATE TO HEAVY
RAIN EXPECTED AS THE MAIN RAIN BAND ROLLS THROUGH OVERNIGHT. THERE
IS SOME POTENTIAL FOR LOW LEVEL WIND SHEAR BUT, IN AGREEMENT WITH
THE PREVIOUS FORECASTER, THERE LOOKS TO BE ENOUGH MIXING DOWNWARDS
OF STRONGER WINDS SO AS TO PREVENT WIDESPREAD LLWS. AFTER THE MAIN
RAIN BAND MOVES THROUGH, SCATTERED LIGHT TO MODERATE SHOWERS ARE
EXPECTED TOMORROW MORNING/AFTERNOON. THERE IS A 15-20% CHANCE OF
THUNDERSTORMS BOTH WITHIN THE MAIN RAIN BAND AND IN SCATTERED
SHOWERS CONTINUING ON SATURDAY. VISIBILITIES ARE ON THE MORE
PESSIMISTIC SIDE IN THE TAFS WITH LOWER VISIBILITIES SUPPORTED BY
LOCALLY MODERATE TO HEAVY RAIN AND STRONG WINDS. THERE IS THE
POTENTIAL FOR VISIBILITIES TO DROP EVEN FURTHER THAN CURRENTLY
LISTED IN THE TAF IF A PARTICULARLY STRONG CELL MOVES OVER THE TAF
SITE.
VICINITY OF SFO...MODERATE RAIN, LOWERED VISIBILITIES, AND STRONG
WINDS WILL IMPACT SFO OVERNIGHT INTO TOMORROW. WINDS STRENGTHEN THIS
EVENING WITH GUSTS TO AROUND 38 KNOTS EXPECTED OVERNIGHT INTO
TOMORROW. THE MAIN RAIN BAND WILL ARRIVE LATE THIS EVENING BRINGING
MODERATE TO AT TIMES HEAVY RAIN BEFORE TRANSITIONING TO MODERATE
SHOWERS EARLY SATURDAY MORNING. WINDS DECREASE MID SATURDAY MORNING
BUT CONDITIONS WILL REMAIN GUSTY BEFORE STRENGTHENING AGAIN LATER IN
THE DAY. GUIDANCE INDICATES SOME POTENTIAL FOR CEILINGS TO LOWER
BELOW 3000 FT AT THE END OF THE TAF PERIOD BUT CONFIDENCE IS LOW.
SFO BRIDGE APPROACH...STRONG, GUSTY WINDS ARE EXPECTED OVER THE
SOUTHERN SF BAY WHICH MAY BRING LOW LEVEL WIND SHEAR CONCERNS TO THE
SFO BRIDGE APPROACH. CURRENT THINKING IS THAT THERE WILL BE ENOUGH
MIXING OF STRONG WINDS WITHIN THE LOWER LEVELS OF THE ATMOSPHERE TO
REDUCE LLWS CONCERNS BUT IT REMAINS A POSSIBILITY. OTHERWISE,
SIMILAR TO SFO.
MONTEREY BAY TERMINALS...WINDS STRENGTHEN THIS AFTERNOON/EVENING
WITH GUSTS TO AROUND 30-35 KNOTS EXPECTED OVERNIGHT. PERIODS OF
MODERATE RAIN AND MODERATE SHOWERS ARE EXPECTED OVERNIGHT AS A
STRONG COLD FRONT PASSES THROUGH THE REGION. WINDS DECREASE BY MID
TOMORROW MORNING WITH SHOWERS DECREASING FROM MODERATE TO LIGHT.
VISIBILITIES MAY DROP FURTHER THAN CURRENTLY LISTED IN THE TAF IF A
STRONG CELL MOVES DIRECTLY OVER THE AIRPORT. ANY ADDITIONAL DROPS IN
VISIBILITY ARE EXPECTED TO BE TEMPORARY.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 904 AM PST FRI JAN 2 2026
GALE FORCE WINDS HAVE DEVELOPED OVER THE NORTHERN WATERS AND WILL
SPREAD ACROSS THE REST OF THE COASTAL WATERS TODAY. LOCALIZED
STORM FORCE WINDS ARE POSSIBLE TONIGHT ACROSS THE NORTHERN OUTER
WATERS. WINDS DIMINISH SATURDAY WITH GALE FORCE WINDS CONTINUING
FOR THE NORTHERN WATERS AND STRONG TO NEAR GALE FORCE WINDS
ELSEWHERE. MODERATE RAIN AND A SLIGHT CHANCE OF THUNDERSTORMS
CONTINUES THROUGH THE WEEKEND WITH LIGHT RAIN EXPECTED TO
CONTINUE THROUGH EARLY NEXT WEEK.
BEACHES
ISSUED AT 1236 AM PST FRI JAN 2 2026
A COASTAL FLOOD WARNING IS IN EFFECT FOR THE SAN FRANCISCO BAY
THROUGH SATURDAY. A COASTAL FLOOD ADVISORY IS IN EFFECT FOR THE
PACIFIC COAST AND MONTEREY BAY THROUGH SUNDAY. PERIGEAN SPRING
TIDES (KING TIDES) WILL IMPACT THE REGION THROUGH SUNDAY. THIS IS
DUE TO THE COMBINATION OF THE FULL MOON ON 1/3, LUNAR PERIGEE ON
1/1, AND PERIHELION ON 1/3. IN OTHER WORDS THE EARTH, SUN AND MOON
ARE LINED UP AND CLOSE TO EACH OTHER. IN ADDITION TO THE HIGH
ASTRONOMICAL TIDE, THE INCOMING LOW PRESSURE SYSTEM WILL BRING
STRONG SOUTHERLY WINDS, GENERATING SOME STORM SURGE, PARTICULARLY
ON SATURDAY MORNING. THE COMBINATION OF THESE FACTORS WILL BRING
MODERATE COASTAL FLOODING TO THE LOW-LYING AREAS NEAR SHORELINES
AND TIDAL WATERWAYS DURING HIGH TIDE THROUGH SUNDAY.
ON THURSDAY, THE SAN FRANCISCO TIDAL GAUGE RECORDED 2.1 FT OF
INUNDATION. LOOKING AHEAD, HIGH TIDE IS EXPECTED TO BE 2.2 FT
ABOVE NORMAL AT 9:34 AM FRIDAY, 2.5 FT ABOVE NORMAL AT 10:26 AM
SATURDAY, AND 1.9 FT ABOVE NORMAL AT 11:18 AM SUNDAY. THESE
PREDICTIONS INCLUDE UP TO 1.3 FEET OF STORM SURGE THAT WILL
ENHANCE THE ASTRONOMICAL TIDE AND FLOODING THREAT. A REASONABLE
WORSE CASE SCENARIO (10% EXCEEDANCE CHANCE) IS 2.7 FT OF
INUNDATION ON SATURDAY. THE ALL TIME RECORD IS 2.8 FT FROM
1/27/1983. 2.5 FT HASN'T BEEN REACHED SINCE 1998. HIGH TIDE
VARIES UP TO 90 MINUTES EARLIER OR LATER ALONG THE PACIFIC COAST
AND THROUGH THE SAN FRANCISCO BAY, RESPECTIVELY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...COASTAL FLOOD WARNING UNTIL 2 PM PST SATURDAY FOR CAZ006-506-508.
WIND ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM PST SATURDAY FOR
CAZ006-502>505-509-512-514>518-528>530.
COASTAL FLOOD ADVISORY FROM 2 PM SATURDAY TO 2 PM PST SUNDAY FOR
CAZ006-506-508.
COASTAL FLOOD ADVISORY UNTIL 2 PM PST SUNDAY FOR CAZ505-509-529-
530.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PST
SATURDAY FOR SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 9 PM PST THIS EVENING FOR MRY BAY.
GALE WARNING FROM 9 PM THIS EVENING TO 3 AM PST SATURDAY FOR MRY
BAY.
GALE WARNING UNTIL 3 AM PST SATURDAY FOR PIGEON PT TO PT PINOS 0-
10 NM-PIGEON PT TO PT PINOS 10-60 NM-PT ARENA TO PT REYES 0-
10 NM-PT REYES TO PIGEON PT 0-10 NM.
GALE WARNING UNTIL 9 AM PST SATURDAY FOR PT PINOS TO PT PIEDRAS
BLANCAS 0-10 NM.
GALE WARNING UNTIL 3 PM PST SATURDAY FOR PT ARENA TO PT REYES 10-
60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...KENNEDY
MARINE...KENNEDY
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