651
FXUS66 KMTR 191030
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
330 AM PDT SAT JUL 19 2025
..NEW SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 209 PM PDT FRI JUL 18 2025
- SEASONAL TEMPERATURES THROUGH THE END OF THE WEEKEND. BELOW
NORMAL TEMPERATURES RETURN MONDAY.
- LOCALIZED ELEVATED FIRE WEATHER THREAT CONTINUES ACROSS THE
HIGHER ELEVATIONS WITH DRY CONDITIONS EXPECTED THIS WEEKEND.
- WINDS STRENGTHEN SUNDAY AND MONDAY ALONG THE COAST, THE HIGHER
TERRAIN, AND MOUNTAIN GAPS/PASSES.
SHORT TERM
ISSUED AT 247 AM PDT SAT JUL 19 2025
(TODAY AND TONIGHT)
ANOTHER NIGHT SHIFT AND ANOTHER ROUND OF MARINE LAYER STRATUS.
DESPITE SIMILAR SENSIBLE WEATHER THERE ARE SOME MINOR
DIFFERENCES. THE BEST WAY TO DESCRIBE THE LONGWAVE PATTERN OVER
THE FORECAST AREA IS THE "HIGH PRESSURE SQUEEZE PLAY". A FEW UPPER
LEVEL LOWS (SW BRITISH COLUMBIA, WELL OFFSHORE OF NORCAL, AND
SOCAL/BAJA BORDER) ALL SURROUND AN AREA OF HIGH PRESSURE OVERHEAD.
THE "SQUEEZED" HIGH PRESSURE DIDN'T COMPLETELY ERASE THE MARINE
LAYER, BUT DEFINITELY COMPRESSED IT. PT SUR AND BODEGA BAY
PROFILERS ARE REPORTING A MARINE LAYER DEPTH NEAR 1200-1500 FEET.
THE COMPRESSION OF THE MARINE LAYER IS REFLECTED WITH LOWER CIG
HEIGHTS AT AREA AIRPORTS, SPOTTER REPORTS OF FOG, DRIZZLE/BUCKET
TIPS, AND WEBCAMS SHOWING FOG.
DESPITE A CLOUDY START TO THE WEEKEND INLAND SUNSHINE IS EXPECTED
WITH COASTAL CLOUDS BY THIS AFTERNOON. A SIMILAR SIGHT THAT WE'VE
BEEN SEEING THE PAST FEW DAYS. THAT BEING SAID, THE HIGH PRESSURE
OVERHEAD WILL LEAD TO SLIGHTLY WARMER TEMPERATURES TODAY,
ESPECIALLY AWAY FROM THE COAST. HIGHS WILL GENERALLY BE IN THE
60S/MID 70S COAST/BAYS AND 70S TO LOWER 90S INLAND...LOCALLY UPPER
90S INTERIOR CENTRAL COAST. DESPITE THE WARM UP THESE FORECASTED
HIGHS ARE STILL BELOW NORMAL FOR LATE JULY.
SATURDAY NIGHT INTO SUNDAY MORNING WILL FEATURE ANOTHER MARINE
LAYER PUSH, BUT ON THE COMPRESSED.
ELEVATED FIRE WEATHER CONCERNS REMAIN ABOVE THE MARINE LAYER.
WE'RE PUSHING NEARLY A WEEK OF LITTLE TO NO RELIEF FOR THE HIGH
ELEVATION REGARDING HUMIDITY RECOVERY. CURRENT OBS SHOWS RH BELOW
20% FOR SOME OF THE HIGHER PEAKS.
LONG TERM
ISSUED AT 328 AM PDT SAT JUL 19 2025
(SUNDAY THROUGH FRIDAY)
LONGWAVE PATTERN SHIFT TO KICK OFF THE LONG TERM. THE "HIGH
PRESSURE SQUEEZE PLAY" QUICKLY COMES TO AN END AS THE HIGH GETS
PUSHED SOUTHWARD. THE UPPER LEVEL LOW OVER SW BC AND ITS
ASSOCIATED TROUGH DEEPENS OVER THE PACNW AND NORCAL, WHICH HELPS
WITH THE SOUTHWARD PUSH OF THE HIGH PRESSURE. THE DEEPENING TROUGH
WILL END ANY WARM UP AND DEEPEN THE MARINE LAYER. SUBTLE COOLING
WILL BE SEEN ON SUNDAY WITH MORE WIDESPREAD COOLING ON MONDAY INTO
NEXT WEEK. THE UPPER TROUGH WILL ALSO LEAD TO INCREASING
NORTHERLY FLOW. THE INCREASE IN WIND HAS BEEN ADVERTISED BY THE
MODELS FOR SEVERAL DAYS NOW AND THE 00Z RUN IS NO DIFFERENT.
STRONGEST WINDS WILL BE SUNDAY NIGHT LINGERING INTO MONDAY
AFTERNOON/EVENING OVER THE COASTAL WATERS, HIGHER PEAKS, INLAND
GAPS/PASSES. WHILE NOT STRONG ENOUGH TO WARRANT A WIND ADVISORY
THERE WILL BE A 6-8 HR WINDOW WITH SOME SOLID WIND, ESPECIALLY
THE EAST BAY PASSES. GOES WITHOUT SAYING, BUT THE WINDS WILL
INCREASE FIRE WEATHER CONCERNS TOO. WINDS WILL FINALLY EASE LATE
MONDAY NIGHT.
COOL AND RELATIVELY QUIET WEATHER CONTINUES TOWARD THE END OF THE
MONTH.
AVIATION
(06Z TAFS)
ISSUED AT 1035 PM PDT FRI JUL 18 2025
MVFR-IFR STRATUS EXTENDS FROM THE COASTAL REGIONS INTO THE SONOMA
COUNTY VALLEYS AND THE MONTEREY BAY REGION, WITH SEPARATE PATCHES TO
THE WEST OF THE EAST BAY HILLS. EXTENSIVE INLAND STRATUS WILL
DEVELOP THROUGH THE NIGHT BEFORE RETREATING TO THE IMMEDIATE COAST
LATE SATURDAY MORNING. BREEZY ONSHORE FLOW CONTINUES TO DIMINISH,
TURNING LIGHT OVERNIGHT THROUGH SATURDAY MORNING, WITH THE FLOW
RESUMING IN THE AFTERNOON. STRATUS BEGINS TO RETURN TO THE TERMINALS
SATURDAY EVENING, ALTHOUGH MOST OF THE DEVELOPMENT HAPPENS AFTER THE
END OF THE 24-HOUR TAF PERIOD.
VICINITY OF SFO... THE TERMINAL SITS ON THE EDGE OF A STRATUS DECK
THAT WILL IMPACT THE TERMINAL OVERNIGHT, AS WINDS REMAIN RELATIVELY
LIGHT INTO SATURDAY MORNING. CLEARING IS EXPECTED AROUND 19-20Z.
BREEZY AND GUSTY NORTHWEST WINDS RESUME SATURDAY AFTERNOON. LOW TO
MODERATE CONFIDENCE IN STRATUS RETURNING TO THE TERMINAL SATURDAY
EVENING BEFORE THE END OF THE TAF PERIOD, AND IT MIGHT NOT BE UNTIL
EARLY SUNDAY MORNING THAT STRATUS IMPACTS BEGIN.
SFO BRIDGE APPROACH... SIMILAR TO SFO.
MONTEREY BAY TERMINALS... MVFR-IFR CEILINGS THROUGH THE NIGHT WITH A
LOW PROBABILITY OF LIFR CEILINGS. STRATUS RETREATS TO THE IMMEDIATE
COAST LATE SATURDAY MORNING WITH MODERATE CONFIDENCE ON TIMING,
BEFORE RETURNING TO THE TERMINALS EARLY SATURDAY EVENING. LIGHT
WINDS OVERNIGHT BEFORE BREEZY WEST-NORTHWEST WINDS RESUME SATURDAY
AFTERNOON.
MARINE
(TONIGHT THROUGH NEXT THURSDAY)
ISSUED AT 928 PM PDT FRI JUL 18 2025
LIGHT TO MODERATE WEST OR NORTHWEST BREEZES CONTINUE ACROSS THE
MAJORITY OF THE COASTAL WATERS THROUGH MONDAY WITH WINDS EASING
INTO THE UPCOMING WEEK. STRONG TO NEAR GALE GUSTS ARE EXPECTED TO
DEVELOP SATURDAY NIGHT THROUGH SUNDAY ACROSS THE NORTHERN WATERS.
GUSTY WINDS, POTENTIALLY HAZARDOUS TO SMALL CRAFT, ALSO DEVELOP
EACH AFTERNOON AND EVENING THROUGH THE GOLDEN GATE, INTO THE
DELTA, AND THE FAVORED COASTAL JETS OFF OF PIGEON POINT AND THE
BIG SUR COASTLINE. SLIGHT TO MODERATE SEAS PERSIST THROUGH THE
REMAINDER OF THE FORECAST PERIOD.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT EARLY THIS MORNING FOR SF
BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 9 AM THIS MORNING TO 9 PM PDT THIS
EVENING FOR SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PDT SUNDAY FOR SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT THIS MORNING FOR PT PINOS TO
PT PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT SUNDAY
FOR PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...MM
LONG TERM....MM
AVIATION...DIALH
MARINE...DIALH
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