390
FXUS66 KMTR 171150
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
450 AM PDT SUN AUG 17 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 247 AM PDT SUN AUG 17 2025
- COOL AND CLOUDY TODAY, ESPECIALLY ALONG THE COAST
- PATCHY DRIZZLE OR VERY LIGHT RAIN ALONG THE PACIFIC COAST ON
SUNDAY
- A WARMING TREND IS FORECAST STARTING TUESDAY
SHORT TERM
ISSUED AT 247 AM PDT SUN AUG 17 2025
(TODAY AND TONIGHT)
A LITTLE LESS WET TONIGHT AS WE'RE NOT SEEING AS MUCH AS A MOISTURE
TAP AHEAD OF THE PASSING FRONT COMPARED TO LAST NIGHT. SAID COLD
FRONT IS SLOWLY EXITING THE BAY AREA AND MOVING SOUTH AND EAST WITH
A SLIGHT DRY SECTOR DIRECTLY BEHIND IT. THIS WILL LIMIT SOME OF THE
COASTAL DRIZZLE AS WELL AND CAUSE SOME MIXING OUT OF SOME OF THE
LOWER CLOUDS.
THE COOLER AND SLIGHTLY DRIER AIR FILTERING INTO THE REGION WILL
ALLOW FOR A SLIGHTLY CLEARER DAY FOR THE REGION, BUT STILL LOOKS
TO KEEP SUNDAY THE COOLEST DAY OF THE FORECAST. EXPECT HIGHS TO
RANGE FROM THE 50S ALONG THE IMMEDIATE COAST, 60S TO LOW 70S FOR
AREAS SLIGHTLY INLAND, INTO THE 80S FOR THE INTERIOR, AND THE LOW
90S FOR THE FAR INTERIOR PORTIONS OF MONTEREY CO.
CLOUD COVER DOES LOOK TO QUICKLY FILTER BACK IN TO THE SF BAY THIS
EVENING AND INTO THE NIGHT WITH THE MARINE LAYER SLIGHTLY
COMPRESSING BUT STILL SEEING A GOOD PUSH INLAND.
LONG TERM
ISSUED AT 247 AM PDT SUN AUG 17 2025
(MONDAY THROUGH SATURDAY)
THE MARINE LAYER WILL COMPRESS DUE TO OUR CHANGING UPPER LEVEL
PATTERN THAT PLACES THE REGION BACK INTO A RIDGING SET UP. MODELS
SEEM TO BE IN GOOD AGREEMENT OF STEADY WARMING INTO THE WORK WEEK
AFTER ONLY SLIGHTLY WARMER CONDITIONS FOR MONDAY. AS THE RIDGE OF
HIGH PRESSURE BUILDS, THE INTERIOR AREAS WILL REALLY SEE THE WARMING
TREND WHILE THE IMMEDIATE COAST AND ADJACENT VALLEYS SEE ONLY SLIGHT
WARMING AS THE MARINE LAYER IS SET TO COMPRESS, BUT NOT COMPLETELY
ERODE INTO THE WEEK.
A QUICK NOTE ABOUT THE COAST: THE ASTRONOMICAL SET UP WILL GIVE US A
BIT MORE MOVEMENT IN THE TIDES INTO THE NEXT WEEK. THE HIGH TIDES
WILL BE HIGHER AND THE LOW TIDES WILL BE LOWER. THIS WILL GET HIGH
TIDE LEVELS CLOSE TO COASTAL FLOODING CRITERIA, BUT NOT CROSSING THE
THRESHOLD FOR COASTAL FLOOD ADVISORIES. IT'S STILL WORTH NOTING
BECAUSE PEOPLE MAY BE HEADING TO THE SF BAY SHORELINE TO BEAT THE
HEAT IN THE NEXT FEW DAYS.
METEOROLOGIST SARMENT, TONIGHT'S MARINE FORECASTER, PROVIDED SOME
ADDITIONAL INFO:
"LOCALIZED MINOR COASTAL FLOODING WILL LIKELY OCCUR IN BAYSIDE MARIN
COUNTY THROUGH SUNDAY, AUGUST 24TH AS HIGH TIDES WILL REMAIN IN
EXCESS OF 6.0 FEET. COASTAL LOCATIONS THAT ARE DIRECTLY LOCATED NEXT
TO RICHARDSON BAY SUCH AS SAUSALITO, TAM VALLEY, MANZANITA, THE
SAUSALITO-MILL VALLEY BIKE PATH, AND THE MANZANITA PARK N RIDE CAN
EXPECT NUISANCE FLOODING WHERE TYPICALLY DRY LAND GETS WET. IMPACTS
ARE EXPECTED TO BE MINOR AT MOST - REMEMBER, DO NOT DRIVE AROUND
BARRICADES OR THROUGH WATER OF UNKNOWN DEPTH."
GETTING BACK TO THE LONGER TERM FORECAST, MODELS CONTINUE TO SHOW A
PEAKING/PLATEAUING OF THE WARMING TREND BY THE END OF THE WORK WEEK.
HIGHS LOOK TO BREAK INTO THE 100S FOR THE FAR INTERIOR WITH AROUND
105 DEGREES BEING THE WARMEST FOR THE CWA. THE COAST, HOWEVER LOOKS
TO BE PROTECTED BY A FAIRLY SHALLOW, BUT STILL INTACT MARINE LAYER
WITH HIGHS IN THE 60S AND LOW 70S.
THE BIG QUESTION IN THE LONGER TERM FORECAST IS HOW LONG THE HEAT
PERSISTS. MODELS HINT AT TINY IMPROVEMENTS TO ONSHORE FLOW, BUT
DON'T LOOK TO BREAK THE RIDGE NOR PUSH IT EAST UNTIL THE MIDDLE OF
THE NEXT WORK WEEK. THIS COULD CALL FOR SOME PROLONGED HEAT WITH
ONLY SLIGHT IMPROVEMENTS IN TEMPS. LUCKILY THAT ISN'T SET IN STONE
AND THERE COULD BE MUCH MORE PROMISING CHANGES IN THE NEXT FEW MODEL
AVIATION
(12Z TAFS)
ISSUED AT 446 AM PDT SUN AUG 17 2025
CURRENTLY A MIXED BAG OF LIFR-VFR AT THE TERMINALS WITH SATELLITE
SHOWING JUST A FEW HIGH CLOUDS FROM THE NOW STATIONARY FRONT. THE
MARINE LAYER AND ITS STRATUS HAS IMPRESSIVELY REBOUNDED IN ITS WAKE
WHILE UNHEALTHY STRATUS LIES AHEAD OF IT. WITH THE STATIONARY FRONT
FORECAST TO REMAIN, WELL, STATIONARY THROUGH MOST OF THE TAF
PERIOD, THE FORECAST IS EXTREMELY NUANCED. TO ADD ON TOP OF THAT,
GUIDANCE/MODELS HAVE A VERY POOR IDEA OF WHAT IS UNDERWAY AS MOST
ARE SIGNIFICANTLY OVERDOING CLOUD COVER WHICH WILL UNDOUBTEDLY
PROPAGATE THROUGH THEIR LATER FORECASTS. THUS, CONFIDENCE IS LOWER
THAN NORMAL IN THIS FORECAST, BUT IF STRATUS CAN HOLD OFF ON THE
NORTH BAY TERMINALS OF APC AND STS THIS MORNING (THESE ARE IN
CLOSE PROXIMITY TO THE STATIONARY FRONT), I BELIEVE THAT
OPTIMISTIC FORECAST WILL BE REALIZED AT TERMINALS FARTHER SOUTH
ONCE THE STATIONARY FRONT SAGS SOUTH AND DRIER AIR GETS ADVECTED
INTO THE REGION.
VICINITY OF SFO...CURRENTLY IFR WITH WESTERLY FLOW. WITH THE
STATIONARY FRONT DOING WHAT IT DOES BEST (REMAINING STATIONARY)
THROUGH A MAJORITY OF THE TAF PERIOD, THE FORECAST IS GOING TO BE
EXTREMELY NUANCED. GUIDANCE/MODELS ARE SPLIT WITH ONLY MODERATE
CONFIDENCE NO MATTER HOW YOU SPLIT IT. THE FORECAST WAS CONSTRUCTED
IN A REASONABLE BEST CASE SCENARIO WITH DRY AIR ADVECTION KEEPING
SUB-VFR CEILINGS AWAY FROM THE TERMINAL TONIGHT. REASONABLE WORST
CASE SCENARIO WOULD BE THE CEILING ON THE CUSP OF IFR/MVFR NOT
CLEARING AT ALL THROUGH THE TAF PERIOD. GUSTY WESTERLY WINDS WILL
PREVAIL THROUGH THE TAF PERIOD.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CURRENTLY IFR WITH SOUTHWESTERLY FLOW AT
MRY AND MVFR WITH NORTHWESTERLY FLOW AT SNS. CEILINGS HAVE
CONSISTENTLY RISEN OVER THE PAST 2 HOURS - THAT TREND IS EXPECTED TO
CONTINUE THROUGH THE MORNING WITH HIGH CONFIDENCE IN VFR THIS
AFTERNOON WITH LOW STRATUS CLOUDS STICKING CLOSE TO THE COAST.
MODERATE (50-70%) CONFIDENCE ON SUB-VFR CEILINGS RETURNING TONIGHT -
LIKELY ON THE CUSP OF MVFR/IFR.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 247 AM PDT SUN AUG 17 2025
WIDESPREAD HAZARDOUS CONDITIONS FOR SMALL CRAFT WILL BE PRESENT
TODAY DUE TO THE SEA BREEZE. MODERATE TO FRESH NORTHWESTERLY
BREEZES WILL PREVAIL THROUGH TUESDAY WITH LOCALLY STRONG
NORTHWESTERLY BREEZES ALONG THE COASTAL JET REGIONS OF POINT REYES
AND POINT SUR. MODERATE SEAS WILL PREVAIL THROUGH TUESDAY. BY
WEDNESDAY, NORTHWESTERLY BREEZES WILL INCREASE TO BECOME FRESH TO
STRONG AND SEAS WILL BUILD TO BECOME ROUGH FOR THE OUTER WATERS.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 9 PM PDT THIS
EVENING FOR MRY BAY-PIGEON PT TO PT PINOS 0-10 NM-SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT MONDAY FOR PT ARENA TO PT
REYES 0-10 NM-PT REYES TO PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT MONDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT THIS MORNING FOR PT ARENA TO
PT REYES 10-60 NM.
SHORT TERM...MURDOCK
LONG TERM....MURDOCK
AVIATION...SARMENT
MARINE...SARMENT
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