267
FXUS66 KMTR 150357
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
857 PM PDT THU AUG 14 2025
..NEW UPDATE, MARINE
KEY MESSAGES
UPDATED AT 222 PM PDT THU AUG 14 2025
- A MARINE LAYER WILL BRING COASTAL DRIZZLE THE NEXT FEW
MORNINGS.
- TEMPERATURES WILL WARM SLIGHTLY THROUGH FRIDAY BEFORE RETURNING
BACK BELOW NORMAL THIS WEEKEND.
- STRONG NW WINDS WILL ARRIVE TO THE COAST TODAY AND SPREAD
INLAND FRIDAY - SATURDAY.
UPDATE
ISSUED AT 856 PM PDT THU AUG 14 2025
FORECAST REMAINS ON TRACK THIS EVENING WITH ELEVATED WINDS ALONG THE
COASTAL RANGES AND HIGHER ELEVATIONS OF NORTH AND EAST BAY
PERSISTING TONIGHT, INCREASING FURTHER FOR FRIDAY AFTERNOON/EVENING,
AND THEN STAYING BREEZY FOR SATURDAY. THE INCREASED ONSHORE WINDS
ARE DUE TO PERSISTENT UPPER LEVEL TROUGHING ACROSS OUR AREA WITH
NOWHERE TO GO DUE TO A LARGE AREA OF HIGH PRESSURE BUILDING ACROSS
THE CENTRAL US. COASTAL COMMUNITIES WILL SEE PERIODS OF DRIZZLE
OVERNIGHT INTO FRIDAY MORNING AS WELL.
DESPITE THE INCREASED ONSHORE FLOW, TEMPERATURES AWAY FROM THE
MARINE LAYER WILL BE AROUND 5-10 DEGREES WARMER FRIDAY THAN TODAY
WITH A SHORT WINDOW OF OFFSHORE FLOW DEVELOPING WITH HELP FROM THE
EKA-SFO GRADIENT CURRENTLY AROUND 5.5 MB, EXPECTED TO PEAK AROUND 6
MB TONIGHT AND FRIDAY MORNING.
SHORT TERM
ISSUED AT 217 PM PDT THU AUG 14 2025
(THIS EVENING THROUGH FRIDAY)
ANOTHER DAY OF LARGE TEMPERATURE SPREADS ACROSS THE BAY AREA AND
CENTRAL COAST FROM THE COASTLINE TO FAR INTERIOR LOCATIONS.
RATHER COMMON THIS TIME OF YEAR ACTUALLY. UPPER 50S/60S COAST TO
90S INLAND. WHILE WE'VE BEEN HYPING THE COOLDOWN IT'S STILL HOT
INLAND. IN FACT, A FEW INTERIOR LOCATIONS HAVEN'T DROPPED BELOW 90
DEGREES FOR DAYTIME HIGHS SINCE THE LAST WEEK OF JULY.
THE LOW CLOUDS LURKING ALONG THE COAST THIS AFTERNOON WILL MOVE
INLAND AGAIN TONIGHT. HOWEVER, THE EVOLUTION OF THE MARINE LAYER
TONIGHT WILL BE DIFFERENT THAN THE LAST FEW NIGHTS. WHILE THE
MARINE LAYER BEGINS TO MARCH INLAND IT WILL BE SLOWED/HAMPERED BY
SOME WEAK OFFSHORE FLOW AND ENTRAINMENT OF DRIER AIR. WEAK SURFACE
HIGH PRESSURE WILL CONTINUE TO BUILD ALONG THE OR/CA BORDER
RAMPING UP THE N-S GRADIENT TONIGHT. LARGER SCALE OFFSHORE
GRADIENT ALSO BEGINS TO RAMP UP TONIGHT AND EARLY FRIDAY.
THEREFORE, STRATUS COVERAGE WILL BE LESS FOR LOCATIONS NORTH OF
APPROX. HALF MOON BAY. AREAS SOUTH, WILL FEEL LESS INFLUENCE FROM
THE PRESSURE GRADIENTS SO IT WILL BE MORE OF THE SAME -
CLOUDS/DRIZZLE.
THE BIGGER WEATHER IMPACT ON FRIDAY CONTINUES TO BE THE WIND. A
LARGE SCALE UPPER LEVEL TROUGH WILL SETTLE IN REINFORCING
PRESSURE GRADIENTS. WEST TO NORTHWEST WINDS WILL INCREASE THOUGH
THE DAY FRIDAY AND PEAK FRIDAY AFTERNOON/EVENING. 20-40 MPH GUSTS
SEEM PLAUSIBLE WITH SOME PEAK GUSTS OF 50 MPH.
LONG TERM
ISSUED AT 217 PM PDT THU AUG 14 2025
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
GRADIENTS RELAX OVER THE WEEKEND WITH DECREASING WINDS. EXPECT THE
MARINE LAYER TO BECOME MORE WIDESPREAD WITH DRIZZLE. COOLER
WEATHER WITH LONGWAVE BROAD TROUGHING CONTINUES THROUGH MONDAY. A
FOUR CORNERS RIDGE OF HIGH PRESSURE BEGINS TO NUDGE IN FROM THE
EAST BY TUESDAY KICKING OFF A WARMING TREND. ALL IN ALL, PRETTY
MELLOW LONG TERM FORECAST.
AVIATION
(00Z TAFS)
ISSUED AT 451 PM PDT THU AUG 14 2025
IT'S VFR EXCEPT VISIBLE SATELLITE IMAGERY SHOWS COASTAL STRATUS
AND FOG /MVFR-IFR/ FROM POINT REYES SOUTHWARD. SEA BREEZES WILL
PREVAIL AT THE TERMINALS DURING THE PERIOD, USHERING STRATUS AND
FOG /MVFR-IFR/ INLAND TONIGHT AND FRIDAY MORNING. CONDITIONS WILL
IMPROVE TO MVFR-VFR BY LATE FRIDAY MORNING AND EARLY AFTERNOON.
VICINITY OF SFO...VFR, HOWEVER STRATUS IS SEEN ON THE WEBCAM IN
THE SAN BRUNO GAP WITH WESTERLY WIND GUSTS 30 KNOTS AND THIS MAY
BRIEFLY BRING IN STRATUS DURING THE EVENING. WILL WAIT FOR NOW
BEFORE MAKING ANY AMENDMENTS. WEST WIND DECREASING TONIGHT AND
FRIDAY MORNING, THEN INCREASINGLY GUSTY TO 30 KNOTS FRIDAY AFTERNOON
TO MID EVENING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...COASTAL STRATUS AND FOG IS MOVING INLAND
ALONG THE MONTEREY BAY. MVFR-IFR CONDITIONS DEVELOPING THIS EVENING
AND PREVAILING TONIGHT AND FRIDAY MORNING. CONDITIONS LIFTING TO
MVFR-VFR BY LATE FRIDAY MORNING AND AFTERNOON. ONSHORE WINDS 5 TO
15 KNOTS EXCEPT AFTERNOON AND EARLY EVENING GUSTS TO 20 KNOTS.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 856 PM PDT THU AUG 14 2025
EXPECT WIDESPREAD HAZARDOUS CONDITIONS THROUGH SATURDAY DUE TO
STRONG NORTHWESTERLY BREEZES WITH GALE FORCE GUSTS ESPECIALLY FOR
THE OUTER WATERS AND COASTAL JET REGIONS OF POINT REYES AND POINT
SUR. THE BAYS WILL EXPERIENCE HAZARDOUS CONDITIONS FRIDAY 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 FROM 3 PM TO 9 PM PDT FRIDAY FOR MRY BAY-SF
BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR MRY BAY-
PIGEON PT TO PT PINOS 0-10 NM-PIGEON PT TO PT PINOS 10-60
NM.
GALE WARNING UNTIL 9 PM PDT FRIDAY FOR PT ARENA TO PT REYES 0-10
NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT FRIDAY FOR PT REYES TO
PIGEON PT 0-10 NM.
SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PDT FRIDAY FOR PIGEON PT
TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT FRIDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
GALE WARNING FROM 9 AM TO 9 PM PDT FRIDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
GALE WARNING UNTIL 9 AM PDT FRIDAY FOR PT ARENA TO PT REYES 10-
60 NM.
GALE WARNING UNTIL 9 AM PDT FRIDAY FOR PIGEON PT TO PT PINOS 10-
60 NM.
SHORT TERM...MM
LONG TERM....MM
AVIATION...CANEPA
MARINE...CANEPA
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