114
FXUS66 KMTR 311740
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1040 AM PDT SAT MAY 31 2025
..NEW AVIATION
SYNOPSIS
ISSUED AT 825 AM PDT SAT MAY 31 2025
HIGH PRESSURE REMAINS IN PLACE, WITH HAZARDOUS HEAT EXPECTED ACROSS
OUR INLAND AREAS ONCE AGAIN TODAY. GIVEN THE DRY CONDITIONS, EXPECT
ELEVATED FIRE WEATHER CONDITIONS TO CONTINUE AS WELL. HOWEVER,
AN UPPER LEVEL TROUGH WILL BRING COOLER CONDITIONS TO THE REGION,
WITH MORE SEASONAL TEMPERATURES EXPECTED BY THIS COMING WEEK.
UPDATE
ISSUED AT 825 AM PDT SAT MAY 31 2025
WATER VAPOR IMAGERY SHOWS HIGH PRESSURE SITUATED OVER NORTHERN
CALIFORNIA THIS MORNING, WITH AN UPPER LEVEL TROUGH TO OUR
NORTHWEST AND AN UPPER LEVEL LOW JUST WEST OF BAJA. AS A RESULT,
OUR MARINE LAYER REMAINS VERY COMPRESSED AND SOMEWHAT PATCHY,
WITH THE FORT ORD PROFILER SHOWING IT ABOUT 800 FEET DEEP THIS
MORNING. THIS COMPRESSED MARINE LAYER BROUGHT DENSE FOG TO THE
IMMEDIATE COAST LINE THIS MORNING FROM APPROXIMATELY HALF MOON BAY
SOUTHWARD THROUGH MONTEREY COUNTY. AT THIS TIME, VISIBLE IMAGERY
SHOWS A BIT OF AN OTTER EDDY IN THE MONTEREY BAY, WHICH IS HELPING
TO PULL THE MARINE LAYER OUT. AS A RESULT, VISIBILITIES ARE
IMPROVING ACROSS MUCH OF THE COASTAL AREA MORE QUICKLY THIS
MORNING THAN WE EXPERIENCED YESTERDAY. THE ONLY SITES STILL
REPORTING VISIBILITIES AT OR BELOW A MILE ARE WATSONVILLE AND
FORT ORD. THEREFORE, EXPECT TO CANCEL THE DENSE FOG ADVISORY BY 9
AM.
THE OTHER MAIN CONCERNS FOR THE DAY REMAIN WITH THE HEAT EXPECTED
ACROSS OUR INLAND AREAS AND THE ELEVATED FIRE WEATHER CONDITIONS.
AT THIS TIME, MOST LOCATIONS ARE RUNNING 3 TO 8 DEGREES WARMER
THAN THIS TIME YESTERDAY, AND GIVEN THE LESS EXTENT OF THE MARINE
LAYER THIS MORNING, BELIEVE MOST LOCATIONS WILL BE SIMILAR TO OR
A DEGREE OR TWO WARMER THAN YESTERDAY. THEREFORE, THE HEAT
ADVISORY REMAINS IN PLACE FOR THE FAR INLAND AREAS TODAY, AND THAT
LOOKS ON TRACK.
AS FOR THE UPPER LEVEL LOW TO OUR SOUTH, SATELLITE IMAGERY SHOWS
PLENTY OF MID AND UPPER LEVEL MOISTURE SPREADING INTO SOUTHERN
CALIFORNIA AT THIS TIME, AND WHILE SOME OF THIS MORNING MAY CREEP
AS FAR NORTH AS MONTEREY COUNTY, THE BEST INSTABILITY AND MOISTURE
REMAIN TO OUR SOUTH. THEREFORE, WHILE WE CANNOT COMPLETELY RULE
OUT SOMETHING POPPING IN SOUTHERN MONTEREY COUNTY TODAY, THE
THREAT IS MINIMAL AT BEST.
AS FOR THE UPPER LEVEL TROUGH OFF THE PACIFIC NORTHWEST, IT WILL
MOVE INLAND OVER THE NEXT 24 HOURS, AND BRING COOLER CONDITIONS AS
WELL AS A DEEPENING MARINE LAYER. PALMER
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 355 AM PDT SAT MAY 31 2025
KEY MESSAGES
-MODERATE HEATRISK FOR FAR INTERIOR LOCATIONS AND THE SANTA CLARA
VALLEY, WHICH IS WHERE A HEAT ADVISORY WILL GO INTO EFFECT LATER
TODAY.
-ELEVATED FIRE WEATHER CONCERNS TODAY.
-NON-ZERO CHANCE FOR HIGH-BASED CONVECTION SATURDAY
STRATUS IS NOT AS WIDESPREAD THIS MORNING WITH THE NARROW RIBBON
STARTING ALONG THE MARIN COAST AND SPANNING DOWN OUR CENTRAL COAST.
EXPECT ANY INTERIOR LOCATIONS IMPACTED BY STRATUS OR FOG TO MIX OUT
BY MID TO LATE MORNING. HIGH TEMPERATURES TODAY BEGIN TO MODERATE
SOME AS UPPER LEVEL RIDGING GETS SQUASHED BY A TROUGH TO OUR NORTH
AND A CUT OFF LOW TO OUR SOUTH. HIGH TEMPERATURES THIS AFTERNOON
LOOK TO BE ABOUT 5 TO 15 DEGREES ABOVE NORMAL, WHERE FAR INTERIOR
LOCATIONS COULD REACH THE UPPER 90S TO AROUND 100 DEGREES. THE
SPREAD FOR TODAY WILL BE MUCH LIKE YESTERDAY, AS THE COAST WILL HAVE
THE NATURAL AC GOING FOR IT AGAIN. ANOTHER DAY OF ELEVATED FIRE
WEATHER CONCERNS ARE ON TAP AS, RH VALUES LOOK TO BE ON THE LOWER
END AGAIN WITH ANOTHER NIGHT OF POOR TO MODERATE RECOVERY FOR THE
HIGHER POINTS OF TERRAIN. THE FINAL NOTE FOR SATURDAY IS THE
CONTINUED LOW END THREAT FOR CONVECTION, WHICH REMAINS BELOW 10%.
LIMITING FACTORS WILL BE CAPE (INSTABILITY/ENERGY) AND MOISTURE, DUE
TO THE UPPER LEVEL RIDGE IN PLACE. EXPECT TO POTENTIALLY SEE SOME
CUMULUS POTENTIALLY POP UP OVER OUR TERRAIN, FAVORING MONTEREY AND
SAN BENITO COUNTIES, BUT THERE COULD ALONG THE DIABLO RANGE AND INTO
THE INTERIOR NORTH BAY MOUNTAINS. THE BEST CHANCE FOR ELEVATED
THUNDERSTORMS LOOKS TO BE IN MONTEREY/SAN BENITO AREAS IF IT DOES
OCCUR.
LONG TERM
(SUNDAY THROUGH FRIDAY)
ISSUED AT 355 AM PDT SAT MAY 31 2025
KEY MESSAGES
-PATTERN CHANGE AND COOL DOWN ON SUNDAY
-MARINE LAYER RETURNS, MORE SEASONAL WEATHER NEXT WEEK
HIGH PRESSURE IS OUT OF THE PICTURE BY SUNDAY AS THE CUTOFF LOW TO
OUR SOUTH NUDGES NORTH AND EASTWARD, AND TROUGHING SAGS INTO NORCAL.
THIS WILL BRING A REPRIEVE IN TEMPERATURES DROPPING US EITHER NEAR
NORMAL TO 10 DEGREES BELOW NORMAL FOR THIS TIME OF YEAR. BY LATE
SUNDAY INTO MONDAY, THE SOUTHERN CUTOFF LOW ADVANCES EAST WHILE THE
TROUGH TO OUR NORTH CUTS OFF AND THEN SLIDES TOWARDS DOWN THE CA
COAST MONDAY AND MAKES IT TO SOCAL BY TUESDAY. THE SIGNAL FOR IT
RETROGRADING SOME ON MONDAY DOESN'T APPEAR IN THE LATEST GUIDANCE,
BUT IT WILL BE SOMETHING TO KEEP AN EYE ON. OUTSIDE OF THAT, THE
MARINE LAYER LOOKS WHICH COULD BRING SOME FOG AND COASTAL DRIZZLE.
LOOK FOR TEMPERATURES TO GRADUALLY RETURN TO NEAR NORMAL THROUGH
THE WEEK.
AVIATION
(18Z TAFS)
ISSUED AT 1016 AM PDT SAT MAY 31 2025
VFR WILL PERSIST FOR ALL TERMINALS THROUGH THE AFTERNOON AND
EVENING. INLAND SITES SHOULD REMAIN VFR THROUGH THE FORECAST
PERIOD WITH A SLIGHT CHANCE OF MVFR/IFR CEILINGS EARLY SUNDAY
MORNING.
VICINITY OF SFO...VFR CONDITIONS WILL PERSIST THROUGH THE
REMAINDER OF THE DAY AND INTO THE OVERNIGHT HOURS, WITH MVFR/IFR
CEILINGS POSSIBLE A HOUR OR TWO BEFORE SUNRISE SUNDAY MORNING WITH
A COMPRESSED MARINE LAYER HUGGING THE COAST. PATCHY DENSE
FOG/DRIZZLE WILL ALSO BE POSSIBLE IN VICINITY OF THE BAY AREA
TERMINALS OVERNIGHT INTO SUNDAY MORNING. GUSTY ONSHORE WINDS WILL
PICK UP THIS AFTERNOON AND BEGIN TO EASE AFTER SUNSET.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR CONDITIONS WILL PERSIST THROUGH THE
REMAINDER OF THE DAY AND EARLY EVENING IFR/LIFR CIGS LIKELY LATER
THIS EVENING AFTER SUNSET. EXPECT TO CLEARING SUNDAY MORNING TO BE
SIMILAR TO TODAY, AROUND THE 15Z-16Z TIME PERIOD. DENSE
FOG AND DRIZZLE ARE ALSO POSSIBLE WITH THE COMPRESSED MARINE LAYER
HUGGING THE COASTLINE.
MARINE
(TODAY THROUGH THURSDAY)
ISSUED AT 355 AM PDT SAT MAY 31 2025
BREEZY TO GUSTY CONDITIONS CONTINUE OVER THE NORTHERN COASTAL
WATERS RESULTING IN STEEP WIND WAVES AND HAZARDOUS CONDITIONS FOR
SMALL CRAFTS. WINDS STRENGTHEN STARTING LATE SATURDAY INTO SUNDAY
WITH GALE FORCE GUSTS EXPECTED OVER THE NORTHERN COASTAL WATERS
AND STRONG GUSTS ACROSS THE SOUTHERN OUTER WATERS. ROUGH SEAS ARE
EXPECTED ACROSS THE OUTER WATERS LATE SATURDAY WITH SIGNIFICANT
WAVE HEIGHTS 10 TO 15 FEET ACROSS THE SOUTHERN OUTER WATERS AND UP
TO 22 FEET ACROSS THE NORTHERN OUTER WATERS. WINDS GRADUALLY EASE
BY TUESDAY BUT SIGNIFICANT WAVE HEIGHTS WILL REMAIN ELEVATED
THROUGH MID TO LATE WEEK.
FIRE WEATHER
ISSUED AT 355 AM PDT SAT MAY 31 2025
ELEVATED FIRE WEATHER CONCERNS WILL PERSIST TODAY. THE MARINE
LAYER IS COMPRESSED TO NEAR SEA LEVEL, WITH HIGHER ELEVATIONS
REMAINING DRY WITH MODERATE TO LOCALLY POOR HUMIDITY RECOVERY
TONIGHT. DAYTIME REMAIN ELEVATED FOR FAR INTERIOR LOCATIONS,
WHILE OTHER AREAS MODERATE SOME. COOLER WEATHER ARRIVES SUNDAY.
PEOPLE SHOULD BE MINDFUL TO AVOID ACTIVITIES THAT COULD SPARK A
GRASS FIRE.
CLIMATE
ISSUED AT 1128 PM PDT TUE MAY 27 2025
RECORD HIGH TEMPERATURES AT THE LONG TERM CLIMATE STATIONS
SATURDAY, MAY 31ST.
STATION MAY 31ST
SANTA ROSA 99F 1970
KENTFIELD 102F 2001
NAPA 103F 2001
RICHMOND 95F 2001
LIVERMORE 104F 2001, 1910
SAN FRANCISCO 90F 2001
SFO AIRPORT 91F 2001
REDWOOD CITY 99F 2001
HALF MOON BAY 77F 1997
OAKLAND DOWNTOWN 89F 2001
SAN JOSE 98F 1970
SALINAS AIRPORT 90F 1997
KING CITY 100F 2001
MTR WATCHES/WARNINGS/ADVISORIES
CA...HEAT ADVISORY UNTIL 8 PM PDT THIS EVENING FOR CAZ504-510-513-
516>518.
PZ...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 AM PDT SUNDAY
FOR SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT THIS AFTERNOON FOR PT ARENA
TO PT REYES 0-10 NM-PT ARENA TO PT REYES 10-60 NM.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 3 AM PDT SUNDAY FOR PT
ARENA TO PT REYES 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT SUNDAY
FOR PT REYES TO PIGEON PT 0-10 NM.
GALE WARNING FROM 3 PM THIS AFTERNOON TO 3 PM PDT SUNDAY FOR PT
ARENA TO PT REYES 10-60 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT SUNDAY FOR PIGEON PT TO PT
PINOS 10-60 NM.
SHORT TERM...KR
LONG TERM....KR
AVIATION...KENNEDY
MARINE...KENNEDY
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