292  
FXUS66 KMTR 251021  
AFDMTR  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN FRANCISCO CA  
321 AM PDT TUE MAR 25 2025  
   
..NEW SYNOPSIS, SHORT TERM, LONG TERM, MARINE
 
 
   
SYNOPSIS
 
 
ISSUED AT 319 AM PDT TUE MAR 25 2025  
 
SUMMERLIKE WARMTH CONTINUES TODAY WITH HIGHS IN THE MID TO UPPER  
80S AND ISOLATED LOW 90S EXPECTED. SEASONAL TEMPERATURES RETURN  
WEDNESDAY AS A WEAK SYSTEM MOVES THROUGH THE AREA. A SERIES OF  
POTENTIALLY MORE IMPACTFUL SYSTEMS WILL ARRIVE THIS WEEKEND INTO  
NEXT WEEK.  
 

 
   
SHORT TERM
 
 
(TODAY AND TONIGHT)  
ISSUED AT 319 AM PDT TUE MAR 25 2025  
 
ABOVE NORMAL TEMPERATURES CONTINUE TODAY WITH HIGHS LARGELY  
ANTICIPATED TO BE IN THE MID TO UPPER 80S. THE WARMEST AREAS WILL BE  
IN INTERIOR MONTEREY AND SAN BENITO COUNTIES WHERE TEMPERATURES ARE  
FORECAST TO BE IN THE LOW 90S. ACROSS THE BOARD, TEMPERATURES ARE  
EXPECTED TO BE A FEW DEGREES HIGHER TODAY THAN THEY WERE YESTERDAY.  
TO PROVIDE SOME CONTEXT AS TO WHY, MODEL GUIDANCE FOR MONDAY  
INDICATED 850 MB TEMPS WOULD BE ABOUT 15C YESTERDAY BUT THE 00Z OAK  
SOUNDING (TAKEN YESTERDAY AFTERNOON BETWEEN 4-5PM) SHOWED 850MB  
TEMPS AROUND 16C. MODEL GUIDANCE IS FORECASTING 850MB TEMPERATURES  
TO BE CLOSER TO 16C TO 17C TODAY WHICH WOULD SUPPORT TEMPERATURES  
WARMING SLIGHTLY HIGHER THAN YESTERDAY. THE MAIN CAVEATS TO THE  
TEMPERATURE FORECAST REMAIN IN WHEN WINDS WILL SWITCH FROM OFFSHORE  
TO ONSHORE, HOW STRONG THOSE WINDS ARE, AND IF INCOMING HIGH LEVEL  
CLOUDS WILL SIGNIFICANTLY DIMINISH HEATING AT THE SURFACE. IN TERMS  
OF THE WIND, WINDS LOOK TO REMAIN FAIRLY LIGHT THROUGHOUT THE DAY  
(GENERALLY LESS THAN 10 MPH). WINDS ARE FORECAST TO REMAIN OFFSHORE  
THROUGH THE EARLY AFTERNOON BEFORE TRANSITIONING TO ONSHORE FLOW BY  
MID AFTERNOON. BOTH THE RAP AND NAM MODELS FAVOR THIS SWITCH  
OCCURRING BETWEEN 2-4PM WHILE THE GFS KEEPS WINDS WEAKLY OFFSHORE  
THOROUGH THE EVENING HOURS. THE LONGER OFFSHORE WINDS PERSIST, THE  
MORE LIKELY THE FORECASTED TEMPERATURES WILL BE ACHIEVED. IF THE  
TRANSITION TO ONSHORE WINDS OCCURS EARLY IN THE DAY, TEMPERATURES  
ARE LIKELY TO BE LOWER AS ONSHORE WINDS WILL TRANSPORT COOLER  
OCEANIC AIR OVER THE LAND AND LIMIT THE AMOUNT OF SURFACE WARMING  
THAT CAN OCCUR.  
 
GUIDANCE CONTINUES TO FORECAST SUBSTANTIAL AMOUNTS OF CAPE ACROSS  
THE BAY AREA AND CENTRAL COAST TUESDAY AFTERNOON/EVENING. IN TERMS  
OF THUNDERSTORMS THERE ARE THREE MAIN INGREDIENTS YOU NEED: A  
MOISTURE, INSTABILITY, AND A SOURCE OF LIFT. THE 00Z OAK SOUNDING  
SHOWS PWAT VALUES AROUND 0.70 INCHES (WHICH REFERS TO THE MAXIMUM  
AMOUNT OF WATER IN A COLUMN OF AIR IF ALL OF THE MOISTURE IN THAT  
COLUMN WERE PRECIPITATED OUT OF IT) WITH FORECAST PWAT VALUES FOR  
TUESDAY AFTERNOON IN THE RANGE OF 0.60-0.70 INCHES. WHILE NOT AS  
MUCH AS WE CAN SEE DURING ATMOSPHERIC RIVER EVENTS, THIS IS ENOUGH  
MOISTURE FOR SOME POTENTIAL STORM DEVELOPMENT. IN TERMS OF  
INSTABILITY, HIGH CAPE VALUES SHOW THAT WE DO HAVE SOME INSTABILITY  
PRESENT WITH DECENT CONDITIONALLY UNSTABLE LOW LEVEL LAPSE RATES.  
HOWEVER, FORECAST SOUNDINGS SHOW BETWEEN 100 TO 300 J/KG OF CIN  
ACROSS THE REGION WHICH IS A FAIRLY SUBSTANTIAL CAP THAT ANY  
CONVECTION WOULD HAVE TO OVERCOME IN ORDER FOR STORMS TO DEVELOP. WE  
ARE ALSO LACKING ANY SUBSTANTIAL LIFTING MECHANISM ACROSS THE REGION  
WITH UPPER LEVEL RIDGING LOCATED OVER THE AREA. AS A RESULT  
THUNDERSTORMS ARE UNLIKELY TO DEVELOP TOMORROW BUT IF A STORM IS  
ABLE TO GAIN SOME SORT OF LIFTING MECHANISM (POTENTIALLY VIA  
OROGRAPHIC LIFTING) AN ISOLATED THUNDERSTORM AND LOCALLY GUSTY WINDS  
MAY BE POSSIBLE. HOWEVER, CONFIDENCE REMAINS LOW IN THUNDERSTORM  
DEVELOPMENT WITH THE MOST LIKELY SCENARIO BEING THAT WE WILL SEE THE  
DEVELOPMENT OF FAIR WEATHER CUMULUS CLOUDS ACROSS THE REGION.  
 

 
   
LONG TERM
 
 
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 319 AM PDT TUE MAR 25 2025  
 
TEMPERATURES WILL COOL BACK DOWN TO SEASONAL VALUES WEDNESDAY  
THROUGH THE END OF THE FORECAST PERIOD AS UPPER LEVEL RIDGING EXITS  
THE REGION AND UPPER LEVEL TROUGHING MOVES IN. HIGHS WEDNESDAY WILL  
GENERALLY BE IN THE MID 60S TO LOW 70S BEFORE A WEAK COLD FRONT  
MOVES THROUGH WEDNESDAY INTO FRIDAY AND FURTHER DROPS TEMPERATURES.  
LIGHT RAIN IS EXPECTED ACROSS THE BAY AREA WEDNESDAY INTO THURSDAY  
WITH UP TO 0.5" ACROSS THE NORTH BAY AND A TENTH OF AN INCH SOUTH OF  
THE GOLDEN GATE BRIDGE. NBM GUIDANCE DOES SHOW A 5-10% CHANCE OF  
THUNDERSTORMS WEDNESDAY TO THURSDAY WITH THIS WEAK SYSTEM. AFTER  
THIS SYSTEM PASSES, HIGH TEMPERATURES THURSDAY TO MONDAY WILL  
GENERALLY BE IN THE UPPER 50S TO LOW 60S ALONG THE COAST AND 60S  
ACROSS THE INTERIOR. RAIN ENTHUSIASTS WILL BE EXCITED FOR THE  
BEGINNING OF APRIL AS A PARADE OF STORM SYSTEMS ENTER THE WEST COAST  
FROM THE END OF MARCH THROUGH THE FIRST WEEK OF APRIL. MULTIPLE  
ROUNDS OF RAIN ARE ANTICIPATED WITH THE FIRST ROUND LOOKING TO TAKE  
PLACE SUNDAY INTO MONDAY. METEOGRAM GUIDANCE FROM THE ECMWF AND GFS  
SUGGEST THAT THIS FIRST ROUND OF RAIN WILL BE LIGHTER THAN  
ADDITIONAL STORMS MOVING IN MID NEXT WEEK (BEYOND THE END OF THIS  
FORECAST PERIOD). IT IS STILL TOO FAR OUT FOR SPECIFIC TOTALS BUT  
ENSEMBLE GUIDANCE REMAINS CONSISTENT IN THE IDEA THAT WE WILL SEE AT  
LEAST ANOTHER 1-2 INCHES OF RAIN FROM THIS EVENT AS A WHOLE WITH  
LOCALLY HIGHER TOTALS POSSIBLE IN FAVORED AREAS.  
 

 
   
AVIATION
 
 
(06Z TAFS)  
ISSUED AT 1027 PM PDT MON MAR 24 2025  
 
CLEAR SKIES CONTINUE, ALLOWING FOR VFR CONDITIONS CURRENTLY. MODELS  
SHOW AGREEMENT THAT VFR WILL PREVAIL THROUGH THE TAF PERIOD FOR MOST  
OF THE TERMINALS. THERE IS A HINT FOR HAZE/FOG BETWEEN 12Z-16Z  
OVERNIGHT, BUT CONFIDENCE IS LOW AT THIS MOMENT. WINDS WILL CONTINUE  
TO REMAIN RELATIVELY LIGHT TO MODERATE THROUGH THE TAF PERIOD, BUT  
WILL GRADUALLY TURN S/SE BY LATE TUESDAY AFTERNOON.  
 
VICINITY OF SFO...VFR THROUGH THE TAF PERIOD WITH A SLIGHT CHANCE  
FOR HAZE OVERNIGHT.  
 
SFO BRIDGE APPROACH...SIMILAR TO SFO.  
 
MONTEREY BAY TERMINALS...VFR THROUGH MOST OF THE TAF PERIOD WITH  
LIGHT TO MODERATE WINDS. WINDS WILL TURN TO S/SE OVERNIGHT. THERE IS  
A CHANCE FOR MVFR CONDITIONS OVER KMRY TUESDAY NIGHT, BUT THERE IS  
UNCERTAINTY AS SOME MODELS SHOW VFR THROUGH THE TAF PERIOD.  
 

 
   
MARINE
 
 
(TODAY THROUGH SUNDAY)  
ISSUED AT 319 AM PDT TUE MAR 25 2025  
 
NORTHERLY LIGHT TO GENTLE BREEZES CONTINUE THROUGH TUESDAY NIGHT  
WITH WINDS TURNING SOUTHERLY AND BECOMING MODERATE TO FRESH BY MID  
WEDNESDAY. SEAS WILL FLUX BETWEEN MODERATE AND ROUGH THROUGH  
WEDNESDAY. CONDITIONS DETERIORATE THURSDAY WHEN A WEST TO  
NORTHWEST BREEZES BECOME FRESH AND SEAS BECOME ROUGH. UNSETTLED  
CONDITIONS CONTINUE THROUGH THE WEEKEND AND INTO THE NEXT WORK  
WEEK AS STORM SYSTEMS MOVE THROUGH THE REGION.  
 

 
   
BEACHES
 
 
ISSUED AT 829 PM PDT MON MAR 24 2025  
 
A BEACH HAZARDS STATEMENT IS IN EFFECT THROUGH WEDNESDAY MORNING  
FOR ALL PACIFIC COAST BEACHES. THE WARM CONDITIONS ON LAND WILL DO  
NOTHING TO THE PACIFIC OCEAN THAT IS 51-57 DEGREES. IN ADDITION  
TO THE COLD WATER SHOCK RISK THAT IS ALWAYS PRESENT, THERE WILL BE  
AN INCREASED RISK FOR SNEAKER WAVES AND RIP CURRENTS. OBSERVE THE  
OCEAN FOR 20 MINUTES BEFORE YOU PICK A SPOT ON THE BEACH, STAY  
OFF OF JETTIES AND ROCKS, KEEP PETS ON A LEASH, WEAR A LIFE  
JACKET, AND NEVER TURN YOUR BACK ON THE OCEAN!  
 

 
   
CLIMATE
 
 
ISSUED AT 410 PM PDT FRI MAR 21 2025  
 
RECORD HIGH TEMPERATURES AT THE LONG TERM STATIONS FOR MARCH 24TH  
AND 25TH.  
 
STATION MARCH 24TH MARCH 25TH  
 
SANTA ROSA 91F IN 1926 88F IN 1952  
KENTFIELD 88F IN 1926 84F IN 1997, 1930  
NAPA 86F IN 1926 85F IN 1988, 1970  
RICHMOND 78F IN 1951 83F IN 1952  
LIVERMORE 82F IN 2022, 2014 82F IN 1997  
SAN FRANCISCO 82F IN 1926 83F IN 1952  
SFO AIRPORT 78F IN 1970 85F IN 1952  
REDWOOD CITY 83F IN 1970 84F IN 1952  
HALF MOON BAY 73F IN 1941 72F IN 1969, 1947  
OAKLAND DOWNTOWN 75F IN 1997 80F IN 1988  
SAN JOSE 84F IN 1926 84F IN 1930  
SALINAS AIRPORT 84F IN 1951 85F IN 1988  
KING CITY 87F IN 1951 87F IN 1988, 1930  
 

 
   
MTR WATCHES/WARNINGS/ADVISORIES
 
 
CA...BEACH HAZARDS STATEMENT THROUGH WEDNESDAY MORNING FOR CAZ006-505-  
509-529-530.  
 
PZ...NONE.  

 
 

 
 
SHORT TERM...KENNEDY  
LONG TERM....KENNEDY  
AVIATION...SO  
MARINE...KR  
 
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