979
FXUS66 KMTR 181101
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
401 AM PDT FRI JUL 18 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 155 PM PDT THU JUL 17 2025
- SLIGHT WARMING TREND TO SEASONAL TEMPERATURES FRIDAY THROUGH
THE WEEKEND BEFORE BELOW NORMAL TEMPERATURES RETURN MONDAY.
- LOCALIZED ELEVATED FIRE WEATHER THREAT CONTINUES ACROSS THE
HIGHER ELEVATIONS WITH DRIER CONDITIONS BEGINNING THIS WEEKEND.
- WINDS STRENGTHEN EARLY NEXT WEEK.
SHORT TERM
ISSUED AT 239 AM PDT FRI JUL 18 2025
(TODAY AND TONIGHT)
RINSE AND REPEAT FOR THE NEAR TERM WEATHER FORECAST WITH LITTLE TO
NO WEATHER IMPACTS. SIMILAR TO THE LAST FEW NIGHTS SATELLITE FOG
PRODUCT ONCE AGAIN SHOWS A SOLID MARINE LAYER OVER THE OCEAN AND
INLAND VALLEYS. WHILE WE WERE EXPECTING SOME COMPRESSION OF THE
MARINE LAYER EARLY FRIDAY MORNING, IT APPEARS TO BE DELAYED BASED
ON OBSERVATIONS. BODEGA BAY PROFILE PUTS THE DEPTH OF THE MARINE
LAYER CLOSE TO 2K FEET, WHICH IS SIMILAR TO 24 HOURS AGO. THAT
BEING SAID, SOME ISOLATED DRIZZLE AND PATCHY FOG WILL BE POSSIBLE
ALONG THE IMMEDIATE COASTLINE THROUGH EARLY FRIDAY MORNING.
TO ROUND OUT THE WORKWEEK - THE MARINE LAYER CLOUDS WILL GRADUALLY
ROLL BACK TO THE IMMEDIATE COAST BY MID MORNING. THIS WILL LEAD TO
SUNNY SKIES INLAND WITH SOME LINGERING COASTAL CLOUDS. THE TIMING
ON THIS ROLL BACK MAY HAPPEN EARLIER THAN THURSDAY THANKS TO A
SQUEEZED UPPER LEVEL RIDGE BUILDING OVER THE BAY AREA. THE
BUILDING RIDGE WILL KICK OF A WARMING TREND TODAY LASTING INTO THE
WEEKEND. BUILDING HIGH PRESSURE ALOFT WILL ULTIMATELY COMPRESS THE
MARINE LAYER EVEN IF DIDN'T FRIDAY MORNING. IF ONE LOOKS AT 24
HOUR TEMP TRENDS THIS AFTERNOON THEY'LL LIKELY SEE WARMER
TEMPERATURES ACROSS THE INTERIOR AS HIGH SOAR INTO THE UPPER 80S
TO 90S. INTERIOR CENTRAL COAST HAS A SHOT AT REACHING THE UPPER
90S. DESPITE THE WARM UP, IT IS JULY AND CLIMO/OVERNIGHT COOLING
WILL KEEP HEATRISK CONCERNS IN THE THE MINOR CATEGORY.
COASTAL/BAY SHORELINE WON'T SEE MUCH OF A WARM UP GIVEN THE
ONSHORE FLOW/LINGERING MARINE LAYER CLOUDS.
FRIDAY NIGHT INTO SATURDAY WILL FEATURE ANOTHER ROUND OF MARINE
LAYER CLOUDS, BUT MORE COMPRESSED. THEREFORE, PATCHY FOG AND
DRIZZLE WILL BE MORE LIKELY FRIDAY NIGHT.
ABOVE THE MARINE LAYER EARLY FRIDAY MORNING AND FRIDAY NIGHT INTO
SATURDAY WILL CONTINUE TO FEATURE ELEVATED FIRE WEATHER CONCERNS
GIVEN THE DRY AIR. OBS FRIDAY MORNING SHOW VALUES IN THE 10-30%
RANGE WILL IS GENERALLY CONSIDERED POOR. THANKFULLY, WINDS
AREN'T OVERLY STRONG.
LONG TERM
ISSUED AT 259 AM PDT FRI JUL 18 2025
(SATURDAY THROUGH THURSDAY)
HIGHER 500MB HEIGHTS AND STRONGER HIGH PRESSURE ALOFT ON SATURDAY
WILL YIELD LESS MARINE LAYER CLOUDS AND WARMER TEMPERATURES. THE
FORECAST AWAY FROM THE COAST ON SATURDAY HAS ACTUALLY TRENDED
WARMER FOR SATURDAY. INTERIOR CENTRAL COAST LOCATIONS WILL HAVE A
SHOT AT REACHING 100 DEGREES WITH A 20-30% CHANCE OF EXCEEDING 100
DEGREES. HEATRISK VALUES STILL REMAIN IN THE MINOR WIT A FEW
POCKETS OF MODERATE HOWEVER.
THE WARMER UP ENDS BY SUNDAY AS THE RIDGE GETS SHUNTED SOUTHWARD
WITH ANOTHER TROUGH DIGGING SOUTHWESTWARD INTO CA. THE RETURNING
UPPER LEVEL TROUGHING WILL BRING COOLER TEMPERATURES AND A DEEPER
MARINE LAYER BACK TO THE BAY AREA AND CENTRAL COAST LATE SUNDAY
INTO MONDAY. IT HAS BEEN NOTED ON THE PREVIOUS FEW DISCUSSIONS
THE RETURNING TROUGH WILL USHER IN SOME STRONGER WINDS BY MONDAY.
LATEST ENSEMBLES AND EXTREME FORECAST INDEX HIGHLIGHT THE
SACRAMENTO VALLEY/DELTA REGION/EAST BAY GAPS/PASSES. NO WIND
ADVISORY NEEDED AT THE TIME, BUT THE GUSTY WINDS WILL INCREASE
FIRE WEATHER CONCERNS ON MONDAY AND POSSIBLY INTO TUESDAY. MOST
NOTABLY WILL BE THE HIGHER BURN INDEX AS IT IS MORE SENSITIVE TO
WIND.
SEASONABLY COOL WEATHER PERSISTS FOR MUCH OF NEXT WEEK.
AVIATION
(12Z TAFS)
ISSUED AT 401 AM PDT FRI JUL 18 2025
STRATUS /MVFR-LIFR/ CONTINUES TO MOVE INLAND ON ONSHORE WINDS THIS
MORNING. STRATUS MIXES OUT BY LATE MORNING AND AFTERNOON THEN PER
HREF OUTPUT IS FORECAST TO MOVE BACK INLAND TONIGHT AND SATURDAY
MORNING. OTHERWISE EXPECT VFR CONDITIONS, BEST CHANCE OF VFR WILL
BE FAR INLAND.
VICINITY OF SFO...MVFR CEILING UNTIL 18Z TODAY THEN VFR THROUGH
THE AFTERNOON AND EARLY EVENING. STRATUS /MVFR/ CEILING RETURNS
TONIGHT AND SATURDAY MORNING. WEST WIND 5 TO 10 KNOTS THIS MORNING,
INCREASING TO NEAR 20 KNOTS THIS AFTERNOON AND EARLY EVENING. WEST
WIND DECREASING TO NEAR 10 KNOTS TONIGHT AND SATURDAY MORNING.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...STRATUS /MVFR-IFR/ UNTIL LATE MORNING OR
EARLY AFTERNOON. STRATUS /MVFR-IFR/ RETURNS TONIGHT AND SATURDAY
MORNING. MAINLY ONSHORE WINDS 5 TO 15 KNOTS.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 354 AM PDT FRI JUL 18 2025
LIGHT TO MODERATE WEST OR NORTHWEST BREEZES CONTINUE ACROSS THE
MAJORITY OF THE COASTAL WATERS THROUGH THIS WEEKEND. GUSTY WINDS,
POTENTIALLY HAZARDOUS TO SMALL CRAFT, DEVELOP EACH AFTERNOON AND
EVENING THROUGH THE GOLDEN GATE AND INTO THE DELTA AS WELL AS THE
FAVORED COASTAL JET ALONG THE BIG SUR COASTLINE. MODERATE SEAS
PERSIST THROUGH THE REMAINDER OF THE FORECAST PERIOD.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 AM PDT
SATURDAY FOR SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PDT SATURDAY FOR SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 9 PM PDT THIS
EVENING FOR PIGEON PT TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM THIS AFTERNOON TO 3 PM PDT
SATURDAY FOR PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...MM
LONG TERM....MM
AVIATION...CANEPA
MARINE...CANEPA
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