406  
FXUS66 KMTR 111736  
AFDMTR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN FRANCISCO CA  
1036 AM PDT MON AUG 11 2025  
   
..NEW AVIATION, MARINE, BEACHES  
 
   
KEY MESSAGES  
 
UPDATED AT 333 AM PDT MON AUG 11 2025  
 
- MODERATE HEATRISK CONTINUES THROUGH MONDAY FOR PORTIONS OF NORTH,  
EAST, AND SOUTH BAY COUNTIES AND INTERIOR MONTEREY AND SAN  
BENITO COUNTIES.  
 
- ELEVATED FIRE WEATHER CONCERNS PERSIST THROUGH MONDAY GIVEN THE WARM  
AND DRY CONDITIONS COMBINED WITH BREEZY AFTERNOON AND EVENING  
WINDS.  
 
- PATTERN CHANGE TUESDAY, WITH COOLER WEATHER AND COASTAL DRIZZLE  
RETURNING TO THE FORECAST.  
 
 
   
UPDATE  
 
ISSUED AT 850 AM PDT MON AUG 11 2025  
 
MARINE LAYER RAMPED UP SLIGHTLY THIS MORNING. AS SUCH, BETTER  
COVERAGE OF CLOUDS ACROSS THE INLAND VALLEYS, LESS DENSE FOG BEING  
REPORTED, STILL SOME FOG BUT IN THE 3-6 MILE RANGE, AND LESS  
DRIZZLE. SOUTHERLY TRANSPORT FLOW DID ALLOW FOR SOME UPPER LEVEL  
SMOKE FROM THE GIFFORD FIRE TO SNEAK INTO THE FORECAST AREA.  
THANKFULLY, THIS IS MAINLY HIGH LEVEL SMOKE. LATEST SMOKE  
GUIDANCE SHOWS A SHIFT IN TRANSPORT FLOW SO WILL PUSH SOME OF THE  
SMOKE SOUTHWARD AGAIN.  
 
NO UPDATE NEEDED.  
 
ONE MORE DAY OF INLAND HEAT. DETAILS BELOW...  
 
STILL WAITING FOR ALL LATEST GUIDANCE TO COME, BUT WILL BE DOING A  
DEEPER DIVE INTO IVO MOISTURE AND POTENTIAL IMPACTS. IVO DETAILS  
FROM BEFORE DOWN BELOW...  
 
 
   
SHORT TERM  
 
ISSUED AT 333 AM PDT MON AUG 11 2025  
(TODAY AND TONIGHT)  
 
THE FORT ORD PROFILER THIS MORNING SHOWS THE MARINE LAYER AROUND  
1400FT THIS MORNING, WITH THE SPREAD OF THE STRATUS LOOKING TO MATCH  
A MARINE LAYER DEPTH OF 1500FT. STRATUS SHOULD TAKE A TOUCH LONGER  
TO ERODE THIS MORNING, ESPECIALLY FOR THOSE CLOSER TO THE COAST.  
OVERALL, ANOTHER SUNNY DAY IS EXPECTED FOR INTERIOR LOCATIONS WITH  
HIGH TEMPERATURES PEAKING 90S, PERHAPS CLOSER TO THE UPPER 90S TO  
NEAR 105 FOR INTERIOR CONTRA COSTA, SAN BENITIO, AND MONTEREY  
COUNTIES. STRATUS RETURNS TONIGHT AND WILL SEEP INTO THE VALLEYS  
 
 
   
LONG TERM  
 
ISSUED AT 333 AM PDT MON AUG 11 2025  
(TUESDAY THROUGH SUNDAY)  
 
THE PATTERN CHANGE BEGINS ON TUESDAY, THOUGH BE IT, PERHAPS A BIT  
MORE MINIMALLY THAN PREVIOUSLY EXPECTED. A SHORTWAVE TROUGH  
APPROACHES THE PACNW WHICH WILL BEGIN TO FLATTEN THE UPPER LEVEL  
RIDGE. HIGH TEMPERATURES WILL BE A FEW DEGREES COOLER THAN MONDAY,  
WITH THE GRADUAL DECREASE IN TEMPERATURES CONTINUING THROUGHOUT THE  
WEEK. THE MORE SUBSTANTIAL TROUGH, KICKS IN ON WEDNESDAY WHICH WILL  
PAVE THE WAY FOR UPPER LEVEL TROUGHING TO DOMINATE THE FORECAST  
THROUGH THE WEEKEND. LOOK FOR CLOUDY, DRIZZLY, AND FOGGY OVERNIGHTS  
AND SUNNY SKIES FOR INTERIOR LOCATIONS BY THE AFTERNOON.  
 
AN INTERESTING NOTE IN THE FORECAST IS THAT A FEW DETERMINISTIC  
MODELS ARE TRYING TO SHOW MOISTURE FROM TROPICAL DEPRESSION IVO  
BEING PULLED OVER OUR COAST. CAPE SEEMS TO STRUGGLE TO MANIFEST  
GIVEN THE TROUGHING, BUT MIDLEVEL LAPSE RATES ARE INTERESTING AROUND  
7.5-8C/KM. FOR NOW CURRENT THINKING IS PERHAPS WE SEE SOME CUMULUS  
CLOUDS OR PERHAPS SOME HIGH LEVEL CLOUDS. THUNDERSTORM DEVELOPMENT  
LOOKS UNLIKELY AT THIS TIME.  
 
 
   
AVIATION  
 
(18Z TAFS)  
ISSUED AT 1034 AM PDT MON AUG 11 2025  
 
VFR CONDITIONS ARE RETURNING TO INLAND TAF SITES, WITH THE EXCEPTION  
OF HAF WHERE IFR/MVFR IS EXPECTED THROUGH A GOOD PORTION OF THE TAF  
PERIOD. ONSHORE WINDS WILL INCREASE ONCE AGAIN THIS AFTERNOON BEFORE  
EASING AFTER SUNSET AND MORE SO INTO TUESDAY MORNING. HIGH  
CONFIDENCE FOR AN EARLY RETURN OF IFR/MVFR CONDITIONS AT BOTH THE  
BAY AREA AND MONTEREY BAY TERMINALS THIS EVENING OR BY EARLY TUESDAY  
MORNING. THERE IS MODERATE CONFIDENCE FOR LIFR CONDITIONS EARLY  
TUESDAY MORNING AROUND MRY, HAF, AND STS. EXPECTING IFR/MVFR  
(POTENTIALLY IFR CEILINGS IN THE AFOREMENTIONED SITES) TO CLEAR OUT  
SIMILAR TO THIS MORNING BETWEEN 16Z-19Z TUESDAY. ONSHORE WINDS  
INCREASE ONCE AGAIN BY TUESDAY AFTERNOON.  
 
VICINITY OF SFO...VFR. HIGH CONFIDENCE FOR AN INCREASE IN WESTERLY-  
NORTHWESTERLY WINDS TO INCREASE THIS AFTERNOON BEFORE EASING  
SLIGHTLY INTO TUESDAY MORNING. HIGH CONFIDENCE FOR IFR/MVFR CEILINGS  
TO DEVELOP OVER THE BAY AREA TERMINALS LATE THIS EVENING AND PERSIST  
THROUGH MID-MORNING ON TUESDAY. ONSHORE WINDS INCREASE ONCE AGAIN BY  
TUESDAY AFTERNOON.  
 
SFO BRIDGE APPROACH...SIMILAR TO SFO.  
 
MONTEREY BAY TERMINALS...VFR. ONSHORE WINDS INCREASE SLIGHTLY THIS  
AFTERNOON BEFORE DIMINISHING AFTER SUNSET. THERE IS HIGH CONFIDENCE  
FOR IFR CEILINGS TO RETURN THIS EVENING, POTENTIALLY LOWERING TO  
LIFR EARLY TUESDAY MORNING AT MRY.  
 
 
   
MARINE  
 
(TODAY THROUGH SATURDAY)  
ISSUED AT 1034 AM PDT MON AUG 11 2025  
 
NORTHWESTERLY BREEZES WILL BE GENTLE TO MODERATE THROUGH  
WEDNESDAY WITH DIURNALLY DRIVEN AFTERNOON SEA BREEZES BRINGING  
LOCALIZED STRONG GUSTS THROUGH THE DELTA AND ALONG POINT SUR.  
NORTHWESTERLY BREEZES INCREASE THURSDAY TO BECOME FRESH TO STRONG,  
POSING HAZARDOUS CONDITIONS FOR SMALL CRAFT. MODERATE SEAS WILL  
BUILD TO BECOME ROUGH FOR INNER WATERS AND OUTER WATERS THURSDAY.  
 
 
   
FIRE WEATHER  
 
ISSUED AT 908 AM PDT MON AUG 11 2025  
 
ANOTHER NIGHT WITH POOR HUMIDITY RECOVERY ABOVE THE MARINE LAYER.  
MAY SITES IN THE 15-20% RANGE. THIS IS ROUGHLY 5-7 DAYS OF THE  
PATTERN SO THE HILLS ARE CRISPY. THANKFULLY, THE OVERALL FIRE  
WEATHER CONCERNS THE NEXT FEW DAYS WILL BE EASING AS INTERIOR  
HEAT BREAKS AND HUMIDITY BEGINS TO CREEP UPWARD. WHILE THE ERC HAD  
BEEN CLIMBING AND THE FUEL MOISTURE HAD BEEN DROPPING THE 7 DAY  
FORECAST SHOWS A REVERSE WITH DROPPING ERC AND RISING FUEL  
MOISTURE.  
 
 
   
BEACHES  
 
ISSUED AT 1034 AM PDT MON AUG 11 2025  
 
A LONG PERIOD SOUTHWESTERLY SWELL IS IMPACTING THE COAST AND WILL  
CONTINUE TO DO SO THROUGH TUESDAY EVENING. THIS WILL RESULT IN AN  
INCREASED RISK FOR SNEAKER WAVES AND RIP CURRENTS, ESPECIALLY ALONG  
SOUTHWEST FACING BEACHES SUCH AS STINSON, SANTA CRUZ BOARDWALK AND  
TWIN LAKES. SNEAKER WAVES CAN UNEXPECTEDLY RUN SIGNIFICANTLY FARTHER  
UP THE BEACH THAN NORMAL, INCLUDING OVER ROCKS AND JETTIES. RIP  
CURRENTS ARE TYPICALLY MORE FREQUENT AND STRONGER IN THE VICINITY OF  
JETTIES, INLETS, AND PIERS. SWIMMERS SHOULD ALWAYS SWIM NEAR A  
LIFEGUARD. REMEMBER, NEVER TURN YOUR BACK TO THE OCEAN!  
 
 
   
MTR WATCHES/WARNINGS/ADVISORIES  
 
CA...BEACH HAZARDS STATEMENT THROUGH TUESDAY EVENING FOR CAZ505-529.  
 
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR SF BAY N  
OF BAY BRIDGE.  
 
SMALL CRAFT ADVISORY FROM 1 PM TO 9 PM PDT TUESDAY FOR SF BAY N  
OF BAY BRIDGE.  
 
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT  
WEDNESDAY FOR PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.  
 
 
 
 
 
SHORT TERM...KR  
LONG TERM....KR  
AVIATION...RGASS  
MARINE...RGASS  
BEACHES...RGASS  
 
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO  
 
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