261
FXUS66 KMTR 160446
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
939 PM PDT FRI AUG 15 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1211 AM PDT FRI AUG 15 2025
- STRONG NW WINDS THROUGH SATURDAY NIGHT.
- MODERATE HEATRISK TODAY IN PORTIONS OF THE INTERIOR NORTH AND
EAST BAY.
- TEMPERATURES WILL COOL THIS WEEKEND.
UPDATE
ISSUED AT 918 PM PDT FRI AUG 15 2025
STRATUS IS ROLLING BACK IN ACROSS THE BAY AREA AND CENTRAL COAST
WITH WIDESPREAD OVERCAST SKIES EXPECTED TONIGHT. THE FORT ORD
PROFILER SHOWS THE MARINE LAYER HAS DEEPEND TO A DEPTH OF
APPROXIMATELY 1500-2000 FT AS UPPER LEVEL TROUGHING REDEVELOPS
ACROSS THE WEST COAST. COASTAL DRIZZLE IS LIKELY TONIGHT AS WE
SEE AN INFLUX OF MOISTURE FROM A LOW PRESSURE SYSTEM OVER THE
PACIFIC NORTHWEST. THE HALF MOON BAY AIRPORT WEB CAMERA IS
CURRENTLY SHOWING DRIZZLE WITH A NEARBY COOP SITE IN PACIFICA
REPORTING 0.03" OF PRECIPITATION OVER THE LAST THREE HOURS. WE'LL
HAVE TO SEE HOW MUCH DRIZZLE IS ABLE TO ACCUMULATE TONIGHT SO STAY
TUNED TOMORROW TO SEE WHAT THE RESULTS ARE.
SHORT TERM
ISSUED AT 230 PM PDT FRI AUG 15 2025
(THIS EVENING THROUGH SATURDAY)
LOTS TO SEE ON THE AFTERNOON SATELLITE IMAGERY OVER CA: STRATUS
OVER THE EPAC/COASTAL WATER, STANDING WAVE CLOUDS DOWNSTREAM OF PT
REYES, OCCASIONAL WISPS OF SMOKE FROM VARIOUS FIRES, SWIRLING
EDDIES ALONG THE SOCAL COAST, AND THUNDERSTORMS POPPING OFF OVER
THE SIERRA. THERE ARE A FEW INTERESTING THINGS TO HIGHLIGHT AT THE
SURFACE TOO: WINDS ARE INCREASING ALONG THE COAST/INLAND AND A
SOLID TEMPERATURE REBOUND INLAND. WE'RE IN A LITTLE BIT OF A
TEMPERATURE ROLLER COASTER AS TEMPERATURES WERE COOL THURSDAY,
TEMPERATURES REBOUNDED TODAY, AND WE'LL SEE ANOTHER COOLDOWN THIS
WEEKEND.
THIS EVENING THROUGH SATURDAY: THE ONSHORE GRADIENT IS PUSHING 3
MB WHILE THE N-S GRADIENT CONTINUES INCREASE AS WELL. THE RESULT?
INCREASING WINDS THIS AFTERNOON AND THIS EVENING. WINDS ARE STILL
THE BIGGEST NEAR TERM IMPACT. IF YOU HAVE EVENING PLANS JUST BE
PREPARED FOR SOME BREEZY TO GUSTY CONDITIONS. THANKFULLY, WINDS
WILL EASE OVERNIGHT AS PRESSURE GRADIENTS RELAX. THE RELAXING
GRADIENTS WILL LEAD TO BETTER STRATUS DEVELOPMENT OVERNIGHT.
ADDITIONALLY, AN UPSTREAM UPPER LEVEL TROUGH WILL REINFORCE
STRATUS DEVELOP TONIGHT. THEREFORE EXPECT MORE STRATUS COVERAGE
ALONG THE COAST AND INLAND, ESPECIALLY N AND E BAY. THE LOW LEVELS
WILL BE MOIST ENOUGH THAT WE'LL LIKELY WRING OUT SOME DRIZZLE
EARLY SATURDAY. SATURDAY WILL BE COOLER THAN FRIDAY WITH SOME
INLAND SUNSHINE, BUT COAST WILL HOLD ONTO SOME CLOUDS. THERE'S
NOTHING IN THE OFFICIAL FORECAST AS OF NOW, BUT ONE THING WE'LL BE
WATCHING CLOSELY WILL BE A CHANCE FOR A FEW WIDELY SCATTERED
SHOWERS LATE SATURDAY AND SATURDAY NIGHT. LATEST NWP CAMS ARE NOW
SUGGESTING A FEW POPCORN SHOWERS RIDING THE TAIL END OF A COLD
FRONT SWEEPING THROUGH NORCAL. IF THEY DO OCCUR IMPACTS WILL BE
MINIMAL FOR THE BAY AREA.
LONG TERM
ISSUED AT 236 PM PDT FRI AUG 15 2025
(SATURDAY NIGHT THROUGH NEXT THURSDAY)
FURTHER COOLING IS EXPECTED ON SUNDAY IN A POST FRONTAL REGIME.
SUNDAY'S MAX TEMPS WILL BE 5 TO 15 DEGREES BELOW NORMAL FOR MID-
AUGUST. BY EARLY NEXT WEEK THE UPPER LEVEL TROUGH FROM SUNDAY
BEGINS TO RETROGRADE AS THE RIDGE OVER THE FOUR CORNERS BUILDS
WEST. THE BUILDING RIDGE OF HIGH PRESSURE WILL KICK OFF A WARMING
TREND SLOWLY ON MONDAY/TUESDAY. MORE WIDESPREAD WARMING RETURN
FOR WEDNESDAY AND THURSDAY AS FAR INLAND LOCATIONS MAKE A RUN AT
TRIPLE DIGIT HEAT AGAIN. AS OF NOW, ENOUGH ONSHORE FLOW REMAINS
NEXT WEEK SO HEAT WILL BE MAINLY CONFINED TO INTERIOR LOCATION. A
VERY COMMON THEME THIS SUMMER.
AVIATION
(06Z TAFS)
ISSUED AT 939 PM PDT FRI AUG 15 2025
INCREASING COASTAL STRATUS, FOG AND DRIZZLE /IFR-LIFR/ DEVELOPING
TONIGHT AND SATURDAY MORNING. INLAND IT'S VFR, HOWEVER STRATUS AND
FOG WILL EXTEND LOCALLY INLAND INTO THE BAY AREA AND NORTH CENTRAL
COAST THROUGH THE EVENING ON GUSTY ONSHORE BREEZES. ONSHORE WINDS
EASING OVERNIGHT AND SATURDAY MORNING BEFORE BECOMING GUSTY AGAIN
IN THE AFTERNOON AND EVENING. CONDITIONS IMPROVING TO MVFR-VFR BY
LATE SATURDAY MORNING AND EARLY AFTERNOON. LOWER LEVEL COOL AIR
ADVECTION WILL DEEPEN THE MARINE LAYER TONIGHT THROUGH SATURDAY.
COASTAL STRATUS RETURNING INLAND SATURDAY NIGHT.
VICINITY OF SFO...GUSTY WEST WIND TO AROUND 35 KNOTS THROUGH 05Z
THIS EVENING, OTHERWISE MVFR-IFR IN STRATUS IS FORECAST TONIGHT AND
SATURDAY MORNING. WEST WIND EASING SOMEWHAT AFTER 05Z OTHERWISE WEST
WIND 25 TO 30 KNOTS. STRATUS /MVFR/ IS FORECAST SATURDAY EVENING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...STRATUS, FOG AND DRIZZLE /IFR-LIFR/
TONIGHT AND SATURDAY MORNING. CONDITIONS IMPROVING TO MVFR BY LATE
SATURDAY MORNING, STRATUS /MVFR/ PREVAILING SATURDAY NIGHT. MAINLY
WEST TO NORTHWEST WINDS 5 TO 15 KNOTS EXCEPT LOCAL GUSTS TO 20 KNOTS
SATURDAY AFTERNOON AND EARLY EVENING.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 918 PM PDT FRI AUG 15 2025
GUSTY NORTHWESTERLY BREEZES WILL CONTINUE OVER THE COASTAL WATERS
TONIGHT TO SATURDAY NIGHT. THE BAYS WILL EXPERIENCE HAZARDOUS
CONDITIONS THIS EVENING AND SATURDAY DUE TO FRESH TO STRONG
WESTERLY BREEZES WITH NEAR-GALE FORCE GUSTS. BREEZES WILL SLOWLY
DIMINISH BY LATE WEEKEND WITH ADDITIONAL EASING OCCURING EARLY
NEXT WEEK. MODERATE TO ROUGH SEAS WILL PREVAIL THROUGH SATURDAY
FOR THE INNER WATERS AND OUTER WATERS WITH MODERATE SEAS BY
SUNDAY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT ARENA TO PT REYES 10-60 NM-SF BAY N OF
BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PDT SATURDAY FOR SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT SATURDAY FOR MRY BAY.
GALE WARNING UNTIL 3 AM PDT SATURDAY FOR PT ARENA TO PT REYES 0-
10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT SATURDAY FOR PT REYES TO
PIGEON PT 0-10 NM.
GALE WARNING UNTIL 9 AM PDT SATURDAY FOR PT PINOS TO PT PIEDRAS
BLANCAS 0-10 NM.
SHORT TERM...MM
LONG TERM....MM
AVIATION...CANEPA
MARINE...CANEPA
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