841
FXUS66 KMTR 040514
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1014 PM PDT THU SEP 3 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1147 AM PDT THU SEP 3 2026
- WELL BELOW NORMAL TEMPERATURES WITH BENEFICIAL RAIN THURSDAY
- HAZARDOUS BEACH CONDITIONS AT PACIFIC COAST BEACHES FRIDAY
THROUGH MONDAY
- BELOW NORMAL TEMPERATURES THROUGH THE WEEKEND, GRADUAL WARMING
AND DRYING TREND MONDAY THROUGH WEDNESDAY
SHORT TERM
ISSUED AT 1147 AM PDT THU SEP 3 2026
(THURSDAY THROUGH THURSDAY NIGHT)
CLOUD COVER WILL INCREASE THROUGH THE DAY AS A COLD FRONT APPROACHES
FROM THE NORTHWEST. FROPA WILL OCCUR THIS AFTERNOON INTO THIS
EVENING FROM NORTHWEST TO SOUTHEAST. THE STANDARD WIND SHIFT FROM
SOUTHEASTERLY TO NORTHWESTERLY WILL OCCUR PRE AND POST-FRONTAL,
RESPECTIVELY, WITH GUSTS UP TO 25 MPH TO BE EXPECTED. GUSTS OF 30-40
MPH ARE EXPECTED THROUGH TERRAIN FAVORED GAPS AND PASSES SUCH AS THE
DELTA, ALTAMONT PASS, AND PACHECO PASS, AS WELL AS DOWN THE SALINAS
VALLEY. FOR THE NORTH BAY, RAINFALL TOTALS UP TO 0.25" WITH LOCALLY
HIGHER AMOUNTS UP TO 0.75" IN THE HIGHER TERRAIN ARE EXPECTED. SOUTH
OF THE GOLDEN GATE BRIDGE, LESS THAN 0.10" IS EXPECTED WITH
ACCUMULATION FAVORING THE COAST AND HIGHER TERRAIN WITH THE HELP OF
OROGRAPHIC LIFT. OVERPERFORMANCE IS STILL A POSSIBILITY WITH THE
STRUGGLES OF GUIDANCE/MODELS IN THE EARLY SEASON. WHILE RAINFALL IS
EXPECTED TO BE BENEFICIAL, WET ROADWAYS WILL CREATE SLICK DRIVING
CONDITIONS AND INCREASE STOPPING DISTANCE. WITH AMPLE LOW-LEVEL
MOISTURE AND POST-FRONTAL CLEARING, THE MARINE LAYER WILL TRY TO
REFORM TONIGHT. AS A RESULT, PATCHY FOG/STRATUS WILL BE POSSIBLE FOR
THE FRIDAY MORNING COMMUTE.
LONG TERM
ISSUED AT 1147 AM PDT THU SEP 3 2026
(FRIDAY THROUGH WEDNESDAY)
THE MOST IMPACTFUL WEATHER PHENOMENON FRIDAY THROUGH MONDAY WILL BE
HAZARDOUS CONDITIONS AT PACIFIC COAST BEACHES. TWO SETS OF LONG
PERIOD SOUTHERLY SWELL FROM DISTANT HURRICANE KARINA AND HURRICANE
MARIE WILL RESULT IN AN INCREASED RISK FOR SNEAKER WAVES AND STRONG
RIP CURRENTS WITH BREAKING WAVES UP TO 10 FEET. WITH PLEASANT
SENSIBLE WEATHER EXPECTED, THESE ARE THE TYPE OF DAYS THAT ARE MOST
DEADLY; WITH IT BEING THE LABOR DAY HOLIDAY WEEKEND, THAT WILL
LIKELY ONLY MAKE MATTERS WORSE. IF YOU WANT AN OUTDOOR ACTIVITY THIS
WEEKEND, HIT THE TRAILS INSTEAD OF THE BEACH. THERE'S GOOD AGREEMENT
THROUGH THE WEEKEND THAT THERE WILL BE AN UPPER-LEVEL LOW OVER THE
PACIFIC NORTHWEST WHICH WILL KEEP OUR REGION UNDER THE INFLUENCE OF
TROUGHING. AS SUCH, EXPECT BELOW NORMAL TEMPERATURES AND ONSHORE
FLOW TO CONTINUE WITH THE RETURN OF THE MARINE LAYER. THE FORECAST
IS NOW DRY THIS WEEKEND WITH THE FARTHER WEST TRACK OF MARIE AND DRY
AIR FILTERING IN FROM THE NORTHWEST. UNCERTAINTY ARRIVES MONDAY IN
TERMS OF LOW VERSUS TROUGH, BUT GLOBAL ENSEMBLE CLUSTERS ARE IN
AGREEMENT THAT THE PATTERN BECOMES PROGRESSIVE AGAIN AS THE LOW
BEGINS TO FILL AND MOVE EAST. THIS WILL ALLOW FOR RIDGING TO BUILD
IN FROM THE DESERT SOUTHWEST, KICKING OFF THE GRADUAL WARMING AND
DRYING TREND. IT IS NOW LOOKING LIKELY THAT AT LEAST SOME OF MARIE'S
REMNANT MOISTURE WILL EVENTUALLY BE BROUGHT INTO OUR AREA AS SOON AS
TUESDAY. WHETHER THIS TRANSPIRES AS CLOUDS OR RAINFALL WILL BE
DEPENDENT ON THE REINFORCING LOW/TROUGH AND THE STRENGTH OF THE
FLANKING RIDGES. RIGHT NOW, THE OFFICIAL FORECAST HAS LIGHT RAINFALL
TUESDAY THROUGH THURSDAY FAVORING THE CENTRAL COAST.
AVIATION
(06Z TAFS)
ISSUED AT 1014 PM PDT THU SEP 3 2026
THE FRONT IS WORKING ITS WAY THROUGH THE BAY AREA AND INTO THE
CENTRAL COAST, WITH LIGHT RAIN BEING REPORTED AT THE TERMINALS
AROUND SAN FRANCISCO. NORTH BAY COUNTIES HAVE DRIED OUT, LEAVING
BEHIND IT CLEARING SKIES AND MAINLY VFR CONDITIONS. THE QUESTION FOR
TONIGHT WILL BE, DO WE CONTINUE TO CLEAR OR WILL BE GET SOME POCKETS
OF SUNRISE STRATUS AND FOG AFTER THE FRONT PASSES? THE LATEST
GUIDANCE LEANS TOWARDS THE LATTER WITH STRATUS AND FOG DEVELOPING
AROUND SUNRISE AND ERODING A FEW HOURS AFTER THAT. VFR CONDITIONS
THEN LOOK TO PREVAIL THROUGH THE FORECAST PERIOD. MEDIUM
CONFIDENCE IN THE FORECAST.
VICINITY OF SFO...THE FRONT IS HERE WHILE WRITING THE AFD AND LIGHT
RAIN IS BEING OBSERVED AROUND THE SAN FRANCISCO BAY TERMINALS ALONG
WITH MVFR CIGS. EXPECT THESE CONDITIONS TO LINGER THROUGH THE NEXT
FEW HOURS, WITH RAIN CHANCES DIMINISHING AS THE FRONT MOVES SOUTH.
THE QUESTION FOR THESE KSFO AND KOAK WILL BE, DOES THE STRATUS LAST.
GUIDANCE SEEMS TO BE THE MOST BULLISH HERE WITH CIGS FLIRTING AROUND
SF BAY. OPTED KEEP THE PESSIMISTIC FORECAST IN, THOUGH IT MIGHT BE
MORE OF A TEMPO SITUATION OR JUST OUTSIDE OF THE RANGE RINGS.
CONDITIONS FOR SURE LOOK TO IMPROVE AROUND AND AFTER SUNRISE, WITH
VFR CONDITIONS PREVAILING DURING THE DAY. ONSHORE WINDS PICK UP MID
TO LATE AFTERNOON, WITH SUSTAINED SPEEDS AROUND 12-15KT AND GUSTS UP
TO 22-25KT THROUGH SUNSET.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...LOW CLOUDS ARE LINGERING AROUND MONTEREY
BAY, WITH HIGH CLOUDS PASSING OVERHEAD AS THE FRONT ARRIVES. LOWER
CLOUDS SHOULD MAKE IT TO KMRY AND KSNS LATER TONIGHT, WITH PERHAPS
EVEN SOME VCSH OR -SHRA FOR A FEW HOURS SEEING HOW WELL THE COLD
FRONT HAS HELD UP. MVFR TO POTENTIALLY IFR CIGS WILL BE POSSIBLE AS
THE FRONT PASSES THROUGH, WITH CONDITIONS GRADUALLY IMPROVING BEHIND
IT.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 1014 PM PDT THU SEP 3 2026
RAIN CHANCES WILL CONTINUE TO DIMINISH TONIGHT, WITH GENTLE TO
MODERATE NORTHWESTERLY BREEZES EXPECTED IN WAKE OF THE FRONTAL
PASSAGE. DIURNAL FRESH TO STRONG GUSTS RETURN WITHIN THE MONTEREY
BAY, THE BIG SUR COAST, AND NEAR POINT REYES FRIDAY INTO THE
WEEKEND. WIDESPREAD FRESH TO STRONG GUSTS RETURN BY EARLY NEXT
WEEK ACROSS THE COASTAL WATERS, DECREASING TO MODERATE TO FRESH
BREEZES BY MIDWEEK. LONG PERIOD SOUTHERLY SWELL ASSOCIATED WITH
TROPICAL ACTIVITY WELL TO OUR SOUTH WILL REACH THE COASTAL WATERS
FRIDAY AND CONTINUE INTO EARLY NEXT WEEK.
BEACHES
ISSUED AT 1010 PM PDT WED SEP 2 2026
A BEACH HAZARDS STATEMENT IS IN EFFECT FRIDAY-MONDAY AS THE SWELL
FROM BOTH HURRICANE MARIE AND HURRICANE KARINA REACHES THE COAST.
AS THESE HURRICANE WHIP UP THE OCEAN, THE WAVES TRAVEL OVER 1,000
MILES IN ALL DIRECTIONS, GRADUALLY FLATTENING OUT TO LOW
AMPLITUDE, BUT LONG PERIOD SWELL. THESE WAVES AREN'T VERY
INTIMIDATING IF YOU'RE ON A BOAT IN THE OPEN OCEAN, BUT THE LONG
PERIOD ALLOWS THEM TO PUSH MUCH FARTHER UP THE BEACH. LONG PERIOD
SWELL ALWAYS INCREASES THE CHANCE FOR SNEAKER WAVES, BUT THAT'S
PARTICULARLY TRUE THIS WEEKEND SINCE THERE ARE 2 DIFFERENT SETS OF
SOUTHERLY SWELL, AND THEIR ENERGY WILL PERIODICALLY COMBINE. IN
ADDITION TO SNEAKER WAVES, EXPECT STRONG RIP CURRENTS AND
BREAKING WAVES UP TO 10 FT. AS THIS IS A HOLIDAY WEEKEND AND THE
WEATHER IS OTHERWISE PRETTY NICE, THE EXPOSURE TO THE RISK IS
HIGH. AVOID THE WATER IF YOU'RE NOT AN EXPERT SWIMMER. IF CAUGHT
IN A RIP CURRENT, SWIM PARALLEL TO SHORE UNTIL YOU STOP FEELING
THE PULL. EVEN ON THE BEACH, BE PREPARED FOR SNEAKER WAVES THIS
WEEKEND AND NEVER TURN YOUR BACK ON THE OCEAN.
MTR WATCHES/WARNINGS/ADVISORIES
CA...BEACH HAZARDS STATEMENT FROM 6 AM PDT FRIDAY THROUGH MONDAY
EVENING FOR CAZ006-505-509-529-530.
PZ...NONE.
SHORT TERM...SARMENT
LONG TERM....SARMENT
AVIATION...KR
MARINE...KR
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