130
FXUS66 KMTR 270349
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
849 PM PDT THU JUN 26 2025
..NEW UPDATE
SYNOPSIS
ISSUED AT 157 PM PDT THU JUN 26 2025
AN INLAND WARMING TREND FRIDAY AND SATURDAY AS HIGH PRESSURE
BUILDS AND THE MARINE LAYER COMPRESSES. BY SUNDAY A WEAK LOW OFF
THE COAST WILL BRING STRONGER ONSHORE FLOW AND DEEPEN THE MARINE
LAYER. THE LOW WILL KEEP TEMPERATURES ON THE COOL SIDE OF NORMAL,
ESPECIALLY INLAND WITH A CONTINUED MARINE LAYER ALONG THE COAST.
UPDATE
ISSUED AT 848 PM PDT THU JUN 26 2025
EVENING SATELLITE AND SURFACE OBSERVATIONS INDICATE AN ON TRACK
FORECAST. THE PREVIOUS DISCUSSION BY RW IS A SOLID LOOK AT THE
DAYS AHEAD. FOR THIS UPDATE, LET'S TALK ABOUT TONIGHT. A WEAK
SURFACE TROUGH OVER THE NORTHERN CALIFORNIA IS SETTING UP A WEAK
OFFSHORE GRADIENT WHICH WILL YIELD SOME OFFSHORE WINDS ACROSS THE
SERVICE AREA, ESPECIALLY OVER THE VACA AND MAYACAMA RANGES. PEAK
WINDS OUT OF THE NE SHOULD ONLY TOP OUT AT ABOUT 25 MPH ALONG THE
HIGHEST PEAKS AND RIDGES IN THE PRE-DAWN HOURS. THAT SAID, THIS
WILL CAUSE HUMIDITY VALUES TO NOT RECOVER AS MUCH AS LOWER
ELEVATIONS IN THE MARINE LAYER. FOR EXAMPLE, LOOK FOR MT ST HELENA
TO STRUGGLE TO REACH 50% RH FOR MAX RECOVERY. ON TOP OF THE
WARMING TREND THAT RW TALKED ABOUT BELOW, THIS WILL CAUSE
CONTINUED DRYING OF FUELS ABOVE ABOUT 1500 FEET, EVEN OVERNIGHT.
MIN TEMPS THE NEXT COUPLE NIGHTS WILL BE CHALLENGED TO DROP BELOW
60F. SO IF YOU LIVE ABOVE THE MARINE LAYER THE NEXT COUPLE NIGHTS,
IT'S GONNA BE ON THE WARMER SIDE.
SHORT TERM
(THIS EVENING THROUGH FRIDAY)
ISSUED AT 157 PM PDT THU JUN 26 2025
SEASONAL WEATHER PATTERN CONTINUES THIS AFTERNOON WITH SUNNY AND
WARM WEATHER INLAND WHILE A 1200 FOOT MARINE LAYER PERSISTS ALONG
THE COAST WITH TEMPS STILL HOVERING IN THE UPPER 50S AND LOWER
60S. STILL NOT SEEING ANY REAL HOT TEMPS INLAND WITH LOWER 90S
CONFINED TO INTERIOR MONTEREY COUNTY. NORTHERLY GRADIENT FROM
SFO-ACV IS NOW IN EXCESS OF 4 MB WITH LESS STRATUS OFF THE SONOMA
COAST. EXPECT THE SHALLOW MARINE LAYER TO SLOWLY REORGANIZE THIS
EVENING AND SPREAD INTO THE COASTAL VALLEYS OVERNIGHT.
BUILDING SHORTWAVE TYPE RIDGE FOR FRIDAY WILL CONTINUE TO COMPRESS
THE MARINE LAYER AND LEAD TO AN INLAND WARMING TREND FRIDAY
AFTERNOON. EXPECT TO SEE LOWER 90S FOR THE INTERIOR
NORTH/SOUTH/EAST BAY FOR THE FIRST TIME THIS WEEK. MICROCLIMATES
SHOULD BE IN FULL EFFECT WITH TEMPS RANGING FROM 60 AT OCEAN BEACH
TO AROUND 95 FOR THE INTERIOR VALLEYS. IT'LL FINALLY FEEL A
LITTLE MORE SUMMER LIKE INLAND FRIDAY AFTERNOON.
LONG TERM
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 157 PM PDT THU JUN 26 2025
NO BIG CHANGES INTO SATURDAY WITH THE RIDGE, SO EXPECT A SHALLOW
MARINE LAYER AND ANOTHER DAY OF INLAND TEMPS IN THE 90S BUT THE
COAST AND BAYS WILL REMAIN MILD TO WARM WITH TEMPS RUNNING NEAR
NORMAL.
BY SATURDAY NIGHT INTO SUNDAY THE MODELS ARE COMING INTO AGREEMENT
THAT A WEAK LOW WILL SPIN UP OFFSHORE, WEST OF SAN FRANCISCO. THIS
WILL LIKELY INDUCE A STRONGER SOUTHWESTERLY ONSHORE WIND PATTERN
ON SUNDAY (KIND OF LIKE A MODIFIED SOUTHERLY SURGE). IN ADDITION
THE UPPER LOW WILL LIKELY DEEPEN THE MARINE LAYER. THEREFORE
EXPECT A NOTED COOLING TREND FOR SUNDAY, ESPECIALLY PLACES LIKE
SANTA CRUZ (NORTH SIDE OF MONTEREY BAY), NAPA AND SONOMA VALLEYS
WHERE SOUTHWESTERLY ONSHORE PUSH WILL BE EFFICIENT FOR PUSHING UP
THOSE VALLEYS.
WORTH NOTING THAT ON SUNDAY NIGHT THE UPPER FLOW TURNS
SOUTHEASTERLY ACROSS NORCAL. GFS MUCAPE SHOWS A FEW 100 J/KG BUT
IT DOESNT ALIGN WITH MOISTURE. BEST FORECAST KEEPS T-STORMS WELL
TO OUR NORTH AND EAST BUT WILL MONITOR CLOSELY AS IT DEPENDS ON
EXACT LOCATION OF UPPER LOW. USUAL SCENARIO WITH THESE SETUPS
WOULD BE CONVECTION OVER THE NORTHERN SIERRA AND THE COASTAL
RANGES FROM MENDOCINO NORTHWARD.
THE UPPER LOW LOOKS TO TAKE UP RESIDENCE FOR MUCH OF NEXT WEEK PER
THE LATEST LONG RANGE MODELS. THAT WOULD MEAN TEMPS RUNNING NEAR
TO A FEW DEGREES BELOW NORMAL FOR LATE JUNE/EARLY JULY WITH A
FAIRLY DEEP MARINE LAYER. THUS AS WE HEAD TOWARDS 4TH OF JULY NOT
SEEING ANY ABNORMALLY HOT WEATHER FOR THE BAY AREA WITH ANY PRECIP
LIKELY STAYING OVER THE SIERRA AND SOUTHERN DESERTS AS MONSOON
MOISTURE SLOWLY STARTS TO EJECT OUT OF AZ AND MEXICO.
AVIATION
(00Z TAFS)
ISSUED AT 511 PM PDT THU JUN 26 2025
STRATUS IS PUSHING BACK INTO COASTAL AREAS, PARTICULARLY ALONG THE
MONTEREY PENINSULA. THE MARINE LAYER LOOKS TO HOLD AROUND 1000 FT
TONIGHT WITH TAFS LARGELY FOLLOWING A PERSISTENCE BASED FORECAST FOR
WHERE STRATUS WILL RETURN. HIGHEST CONFIDENCE IN CIGS RETURNING TO
HAF, MRY, AND SNS WITH LOW TO MODERATE CONFIDENCE IN CIGS AT LEAST
TEMPORARILY RETURNING TO OAK, SFO, AND APC OVERNIGHT. CIGS ARE
LIKELY TO BE ON THE BORDER OF MVFR-IFR WITH THE TAFS LEANING TOWARDS
MVFR GIVEN MORE SITES TRENDED TOWARDS MVFR LAST NIGHT. FOR COASTAL
SITES, CIGS WILL BE MORE ON THE BORDER OF LIFR-IFR WITH SOME
POTENTIAL FOR FOG TO DEVELOP AT HAF AND MRY. WINDS GENERALLY STAY
ONSHORE THROUGH THE PERIOD WITH BREEZY WINDS DURING THE
AFTERNOON/EVENING AND LIGHTER, AT TIMES VARIABLE WINDS OVERNIGHT.
VICINITY OF SFO...MODERATE CONFIDENCE THAT MVFR CIGS WILL BUILD IN
OVERNIGHT WITH SOME POTENTIAL FOR IFR CIGS DURING THE EARLY MORNING
HOURS (12Z-16Z). CONFIDENCE IS LOW AS TO INCLUDING IFR CIGS IN THE
CURRENT TAF BUT WILL CONTINUE TO MONITOR AND ADJUST THE FORECAST AS
NEEDED. CONDITIONS LOOK TO IMPROVE AROUND 18/19Z WITH CLEAR SKIES
THROUGH THE AFTERNOON HOURS. THERE IS SOME POTENTIAL FOR STRATUS TO
RETURN TOMORROW AFTER THE END OF THIS TAF PERIOD BUT CONFIDENCE IS
LOW AT THIS TIME. BREEZY ONSHORE WINDS RETURN DURING THE
AFTERNOON/EVENING WITH GUSTS TO AROUND 20 KNOTS EXPECTED.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...MVFR TO LIFR CONDITIONS CONTINUE THROUGH
TOMORROW MORNING WITH MODERATE CONFIDENCE THAT IFR CIGS WILL RETURN
TONIGHT THROUGH TOMORROW MORNING. THERE IS SOME POTENTIAL FOR
LOWERED VISIBILITY AND FOG AT MRY WITH VISIBILITIES DROPPING TO
AROUND 3SM OVERNIGHT. CONDITIONS IMPROVE MID TO LATE TOMORROW
MORNING WITH SNS CLEARING AROUND 18-19Z. SOME UNCERTAINTY REMAINS AS
TO IF MRY WILL CLEAR TOMORROW MORNING, FOR NOW LEANING TOWARDS
STRATUS PERSISTING BUT THERE IS SOME POTENTIAL FOR CIGS TO CLEAR
AFTER 19Z. BREEZY ONSHORE WINDS CONTINUE DURING THE
AFTERNOON/EVENING BEFORE LIGHTER, MORE VARIABLE WINDS DEVELOP
OVERNIGHT.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 1047 AM PDT THU JUN 26 2025
FRESH TO STRONG NORTHWESTERLY BREEZES WITH NEAR-GALE FORCE GUSTS
WILL CONTINUE THROUGH FRIDAY. GALE FORCE GUSTS CAN BE EXPECTED
NEAR THE COASTAL JET REGIONS OF POINT REYES AND POINT SUR THIS
AFTERNOON AND EVENING. MODERATE TO ROUGH SEAS WILL ALSO CONTINUE
THROUGH FRIDAY, WITH NORTHWESTERLY WINDS EASING OVER THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...COASTAL FLOOD ADVISORY UNTIL 2 AM PDT FRIDAY FOR CAZ006-506-508.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR MRY BAY.
GALE WARNING UNTIL 9 PM PDT THIS EVENING FOR PT ARENA TO PT
REYES 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PIGEON PT TO PT
PINOS 0-10 NM-PT REYES TO PIGEON PT 0-10 NM.
GALE WARNING UNTIL 3 AM PDT FRIDAY FOR PT PINOS TO PT PIEDRAS
BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT SATURDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT ARENA TO PT REYES 10-60 NM.
UPDATE...BFG
SHORT TERM...RW
LONG TERM....RW
AVIATION...KENNEDY
MARINE...RGASS
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