592
FXUS66 KMTR 041150
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
450 AM PDT WED JUN 4 2025
..NEW AVIATION, MARINE
SYNOPSIS
ISSUED AT 205 PM PDT TUE JUN 3 2025
CLOUDY COASTAL MORNINGS FOLLOWED BY BREEZY AND CLEARING AFTERNOONS
WILL THE PREVAILING PATTERN OVER THE NEXT FEW DAYS. COASTAL AREAS
LOOK TO PEAK INTO THE 60S WHILE MORE INTERIOR AREAS STICK TO THE
80S. THE OVERNIGHTS KEEP LOWS IN THE 50S. EXPECT A SLIGHT WARMING
AND DRYING TREND OVER THE WEEKEND AND INTO THE NEXT WORK WEEK.
SHORT TERM
ISSUED AT 241 AM PDT WED JUN 4 2025
(TODAY AND TONIGHT)
KEY MESSAGES
-JUNE GLOOM WITH PATCHY COASTAL DRIZZLE
-BREEZY TO GUSTY ONSHORE FLOW
OVERNIGHT SATELLITE FOG PRODUCT IS DEFINITELY GIVING SOME JUNE
GLOOM VIBES WITH A SOLID STRATUS DECK COVERING: THE COASTAL
AREAS, INTO SF BAY, NORTH BAY VALLEYS, AND SALINAS VALLEY. DECENT
INLAND PENETRATION WITH A MEAGER DEPTH HOVERING AROUND 1200-1500
FEET. PATCHY FOG AND PATCHY DRIZZLE WILL BE POSSIBLE ALONG THE
IMMEDIATE COAST THIS MORNING. IN CLASSIC FASHION THE MARINE LAYER
WILL SLOWLY ERODE BACK TO THE COAST BY THIS AFTERNOON. GIVEN THE
PREVAILING NW FLOW AND BUILDING ONSHORE FLOW COASTAL AREAS WILL
HOLD ONTO SOME CLOUDS THROUGH OUT THE DAY AND NOT FULLY CLEAR. AS
SUCH, WE'LL SEE A PRETTY LARGE SPREAD WITH SENSIBLE WEATHER ALONG
THE COAST TO INLAND AREAS. AKA THE LAND OF MIRCO-CLIMATES.
COASTAL AREAS WILL REMAIN COOL AND IN THE UPPER 50S TO NEAR 70,
WHICH IS SEASONABLY COOL FOR EARLY JUNE. FARTHER INLAND, SUNSHINE
WILL ALLOW FOR A DECENT WARM UP WITH TEMPERATURES MAXING OUT IN
THE 70S TO LOWER 90S, WHICH IS AT OR SEASONABLY MILD FOR EARLY
JUNE. SPEAKING OF ONSHORE FLOW, SFO-SAC GRADIENT WILL INCREASE
THROUGH THE DAY WITH SOME GUIDANCE SUGGESTING 4 TO 5 MB, WHICH IS
PRETTY SOLID. THERE WE'LL SEE SOME STRONGER ONSHORE WINDS THIS
AFTERNOON WITH BREEZY TO GUSTY CONDITIONS ALONG THE COAST, INLAND
VALLEYS,GAPS,AND PASSES. GUSTS 30-40 MPH IN THE WINDIEST
LOCATIONS.
FOR TONIGHT- THE MARINE LAYER WILL RETURN AGAIN WITH MORE COASTAL
DRIZZLE/FOG POSSIBLE. GIVEN THE ONSHORE FLOW INLAND PENETRATION
APPEARS TO BE DECENT AGAIN AND WILL BE SIMILAR TO THIS MORNING.
LONG TERM
ISSUED AT 325 AM PDT WED JUN 4 2025
(THURSDAY THROUGH TUESDAY)
KEY MESSAGES
-TEMPERATURE ROLLER COASTER WITH A GRADUAL WARM UP
-MARINE LAYER REMAINS WITH SOME COASTAL DRIZZLE
INTERESTING LONGWAVE PATTERN CONTINUES TO IMPACT THE WEST COAST
WITH RIDGING HEADING INTO ANOTHER CUT-OFF LOW INTO THE WEEKEND.
CURRENT SETUP SHOWS A BROAD UPPER TROUGH EXTENDING DOWN THE
ALEUTIANS. FARTHER EAST IS A ROBUST AREA OF HIGH PRESSURE OFF THE
WEST COAST EXTENDING INTO THE PACNW. ROUNDING THE EASTERN
PERIPHERY OF THE HIGH ARE EMBEDDED UPPER LEVEL VORT MAX/SHORTWAVE
TROUGHS. SO HOW DOES THIS PATTERN EVOLVE FOR THE LONG TERM? THE
UPPER RIDGE WILL NOSE FARTHER INTO THE PACNW/NORCAL AS PASSING
VORT MAXES/SHORTWAVES DEEPEN/DIG OVER SOCAL WEDNESDAY INTO
THURSDAY. THIS WILL GENERALLY KEEP SENSIBLE WEATHER ON REPEAT:
MARINE LAYER WITH COASTAL DRIZZLE/FOG AND SEASONABLY COOL
TEMPERATURES FOR THURSDAY. BY FRIDAY, ONE OF THE SHORTWAVES
DEEPENS ENOUGH OFF CA TO BECOME CUT-OFF FROM THE MEAN FLOW LEADING
TO ANOTHER MEANDERING UPPER LOW. THE PLACEMENT OF THE LOW AND
NOSING RIDGE WILL KICK OFF A SUBDUED WARMING TREND FRIDAY THROUGH
MONDAY. DESPITE THE WARMING TREND THE MARINE LAYER WILL NOT
COMPLETELY GO AWAY. DAYTIME TEMPERATURES WILL RANGE FROM THE
UPPER 70S TO UPPER 90S AWAY FROM MARINE INFLUENCE. COASTAL/BAYS
WILL BE IN THE UPPER 50S TO LOWER 70S. NOT MUCH OF A HEATRISK
CONCERN DURING THIS TIMEFRAME. GIVEN THE PESKY UPPER LOW
MEANDERING OFF THE COAST ONE ALWAYS HAS TO THINK CONVECTION
POTENTIAL. WHILE SOME OF THE GLOBAL MODELS SHOWS SOME SPOKES OF
UPPER LEVEL MOISTURE PASSING OVERHEAD THUNDERSTORM POTENTIAL AT
THIS TIME SEEMS TO BE CONFINED TO THE SIERRA CREST REGION.
EARLY NEXT WEEK THE UPPER LOW FINALLY MOVES INLAND AND THIS WILL
BRING A SUBTLE COOL DOWN ACROSS THE REGION.
DEFINITELY SOME NUANCES DURING THE LONG TERM, BUT ALL IN ALL
RATHER QUIET WEATHER FOR OUR REGION.
AVIATION
(12Z TAFS)
ISSUED AT 427 AM PDT WED JUN 4 2025
THE MARINE LAYER IS AROUND 1,500 FEET DEEP WITH IFR CEILINGS
REACHING MOST OF THE TERMINALS THIS MORNING. FOR THE COASTAL
SITES, JUNE GLOOM WILL BE IN FULL EFFECT TODAY AS THE STRATUS
ONLY BREAKS FOR A FEW HOURS IN THE AFTERNOON BEFORE RETURNING
EARLY THIS EVENING. VISIBILITY RESTRICTIONS WILL ALSO BE
POSSIBLE, WITH MORE WIDESPREAD AND LONGER DURATION IMPACTS
EXPECTED TOMORROW MORNING AS SLIGHTLY COOLER AIR BRINGS HIGHER
RELATIVE HUMIDITY TO THE BOUNDARY LAYER. DESPITE THE COMPLEXITIES,
THE GFSLAMP HAS MAINTAINED A GOOD HANDLE ON THE SITUATION
OVERNIGHT AND THE AUTHOR OF THE 12Z TAFS RELIED HEAVILY ON ITS
GUIDANCE.
VICINITY OF SFO...SFO IS IN ONE OF THE ONLY PATCHES OF CLEAR SKY,
AND IT'S UNCLEAR EXACTLY HOW LONG THESE CONDITIONS WILL LAST. THE
BEST CHANCE FOR IFR-MVFR CEILINGS IS BETWEEN 13Z AND 16Z, AND THE
TAF HINTS AT THIS WITH A TEMPO LINE AS THE CONDITIONS MAY BE
TRANSIENT. OTHERWISE CLEARING IS EXPECTED THIS AFTERNOON WITH
MODERATE ONSHORE WIND. THERE IS HIGHER CONFIDENCE IN A LONG
DURATION STRATUS DECK TOMORROW MORNING.
SFO BRIDGE APPROACH...THE STRATUS HOLE IS STARTING TO CLOSE IN
THE SOUTH BAY AND THE APPROACH WILL HAVE A HIGHER CHANCE OF
IMPACTS COMPARED TO THE TERMINAL THROUGH THE MORNING HOURS.
MONTEREY BAY TERMINALS...A ROBUST STRATUS INTRUSION IS IMPACTING
THE CENTRAL COAST TERMINALS, AND THESE CONDITIONS WILL PERSIST
THROUGH THE MAJORITY OF THE DAY. WE ARE ONLY EXPECTING AROUND
6 HOURS OF CLEARING THIS AFTERNOON BEFORE AN EARLY RETURN OF
STRATUS THIS EVENING.
MARINE
(TODAY THROUGH MONDAY)
ISSUED AT 427 AM PDT WED JUN 4 2025
THE GRADIENT BETWEEN SUBTROPICAL HIGH PRESSURE OVER THE EASTERN
PACIFIC AND A TROUGH OVER THE COAST OF CALIFORNIA IS SUPPORTING
GALE FORCE WINDS IN THE FAR NW COASTAL WATERS, WITH VERY ROUGH
SEAS. THESE WINDS WILL GRADUALLY DIMINISH OVER THE NEXT 48 HOURS,
WITH MORE FAVORABLE CONDITIONS EXPECTED THROUGH THE REMAINDER OF
THE WEEK. A SOUTHERLY COASTAL JET WILL BRING STRONG ONSHORE WINDS
TONIGHT IN THE SAN FRANCISCO BAY AND IN THE EXPOSED WATERS ACROSS
THE GOLDEN GATE.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 PM PDT THURSDAY
FOR PT REYES TO PIGEON PT 0-10 NM-SF BAY N OF BAY BRIDGE.
GALE WARNING UNTIL 3 AM PDT THURSDAY FOR PT ARENA TO PT REYES 10-
60 NM.
SHORT TERM...MM
LONG TERM....MM
AVIATION...FLYNN
MARINE...FLYNN
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