844
FXUS66 KMTR 191745
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1045 AM PDT SAT JUL 19 2025
..NEW AVIATION
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.
UPDATE
ISSUED AT 932 AM PDT SAT JUL 19 2025
PRETTY WIDESPREAD STRATUS COVERAGE CONTINUES ACROSS MUCH OF THE BAY
AREA AND CENTRAL COAST. OVERCAST SKIES SHOULD CLEAR ACROSS THE
INTERIOR BY LATE THIS MORNING AND PATCHY CLEARING IS EXPECTED ALONG
THE COASTLINE THIS AFTERNOON. HIGHS IN THE UPPER 70S TO LOW 90S
ACROSS THE INTERIOR WITH THE INTERIOR CENTRAL COAST REACHING THE
UPPER 90S TODAY. STILL MONITORING THE POTENTIAL FOR STRONG WINDS
SUNDAY AND MONDAY ALONG THE COAST, MOUNTAIN RIDGETOPS, AND
GAPS/PASSES. OTHERWISE, NO CHANGES TO THE OVERALL FORECAST.
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
(18Z TAFS)
ISSUED AT 1043 AM PDT SAT JUL 19 2025
IFR AT COASTAL SITES AND NORTH BAY SITES THIS MORNING WHILE MVFR
PERSIST ACROSS THE BAY AREA TERMINALS. CONDITIONS WILL RETURN TO VFR
BY AROUND 18Z-20Z THIS AFTERNOON FOR MOST INLAND TAF, WITH THE
EXCEPTION OF HAF WHERE IFR/MVFR CONDITIONS LOOK TO PERSIST THROUGH
MUCH OF THE TAF PERIOD. ONSHORE WINDS INCREASE THIS AFTERNOON BEFORE
EASING AFTER SUNSET. RATHER HIGH CONFIDENCE FOR MVFR CONDITIONS TO
RETURN THIS EVENING BEFORE LOWERING TO IFR BY LATE EVENING AND INTO
SUNDAY MORNING. THE GREATEST POTENTIAL FOR LIFR CONDITIONS WILL BE
ACROSS THE NORTH BAY AND MONTEREY BAY TERMINALS EARLY SUNDAY MORNING
BEFORE CEILINGS BEGIN TO LIFT BY LATE MORNING. CEILINGS CLEAR OUT BY
18Z-20Z FOR MOST COASTAL SITES WITH EARLIER CLEARING ACROSS THE
INTERIOR TAF SITES. ONSHORE WINDS INCREASE ONCE AGAIN BY SUNDAY
AFTERNOON.
VICINITY OF SFO...IFR CURRENTLY BUT ARE FORECAST TO LIFT TO MVFR
BEFORE CLEARING BETWEEN 18Z-20Z. ONSHORE WINDS INCREASE THIS
AFTERNOON BEFORE EASING AFTER SUNSET. HIGH CONFIDENCE FOR MVFR
CEILINGS TO RETURN THIS EVENING BEFORE LOWERING TO IFR EITHER LATE
TONIGHT OR EARLY SUNDAY MORNING. CONDITIONS RETURN TO VFR BY 18Z-20Z
SUNDAY WITH AN INCREASE IN ONSHORE WINDS BY SUNDAY AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR CURRENTLY BUT ARE FORECAST TO LIFT TO
MVFR. LOW CEILINGS WILL SCATTER OUT BY 1930Z-2100Z WITH AN INCREASE
IN ONSHORE WINDS THIS AFTERNOON. HIGH CONFIDENCE FOR EARLY RETURN OF
MVFR CEILING THIS EVENING BEFORE LOWERING TO IFR LATE THIS EVENING
OR EARLY SUNDAY MORNING. GREATEST PROBABILITY FOR LIFR CONDITIONS
EARLY SUNDAY MORNING AT MRY.
MARINE
(TODAY THROUGH THURSDAY)
ISSUED AT 932 AM PDT SAT JUL 19 2025
LIGHT TO MODERATE NORTHWESTERLY BREEZES WILL CONTINUE ACROSS MUCH
OF THE COASTAL WATERS THROUGH SATURDAY NIGHT. GUSTY WINDS,
POTENTIALLY HAZARDOUS TO SMALL CRAFT, ALSO DEVELOP EACH AFTERNOON
AND EVENING THROUGH THE GOLDEN GATE AND INTO THE DELTA. WINDS WILL
INCREASE SLIGHTLY ON SUNDAY BEFORE EASING INTO NEXT WEEK. SLIGHT
TO MODERATE SEAS PERSIST THROUGH THE REMAINDER OF THE FORECAST
PERIOD.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 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 FROM 3 PM THIS AFTERNOON TO 9 PM PDT SUNDAY
FOR PT ARENA TO PT REYES 10-60 NM.
UPDATE...KENNEDY
SHORT TERM...MM
LONG TERM....MM
AVIATION...RGASS
MARINE...RGASS
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