315
FXUS66 KMTR 181740
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1040 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.
UPDATE
ISSUED AT 907 AM PDT FRI JUL 18 2025
STRATUS COVERAGE IS SLIGHTLY LESS WIDESPREAD THAN IT WAS AT THIS
TIME YESTERDAY WITH THE 12Z OAK SOUNDING SHOWING THE MARINE LAYER AT
A DEPTH OF ABOUT 2000 FT. CLOUD COVER WILL CLEAR BY LATE THIS
MORNING BEFORE OVERCAST CONDITIONS RETURN TONIGHT WITH THE MARINE
LAYER TO COMPRESS TO BETWEEN 1500 TO 2000 FT. HIGH TEMPERATURES
WILL BE IN THE 70S TO 80S ACROSS THE INTERIOR TODAY WITH THE
WARMEST LOCATIONS OF THE EAST BAY AND INTERIOR CENTRAL COAST IN
THE 90S. OTHERWISE, THE FORECAST REMAINS ON TRACK.
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 WITH A FEW
POCKETS OF MODERATE HOWEVER.
THE WARM 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
(18Z TAFS)
ISSUED AT 1033 AM PDT FRI JUL 18 2025
MVFR CURRENTLY OVER THE BAY AREA TERMINALS AND AREAS JUST INLAND WAY
FROM THE COAST. HOWEVER, IFR CONDITIONS CONTINUE ACROSS COASTAL
SITES THIS MORNING AND VERY WELL MAY LINGER THROUGH MUCH OF THE DAY.
INLAND TAF SITES SUCH AS LVK AND SJC HAVE CLEARED OUT AND THE REST
OF THE INLAND TERMINALS LOOK TO CLEAR OUT BY LATE MORNING. LOOK FOR
ONSHORE WINDS TO INCREASE THIS AFTERNOON BEFORE EASING AFTER SUNSET
THIS EVENING. HIGH CONFIDENCE FOR IFR/MVFR CONDITIONS TO RETURN TO
MUCH OF THE REGION AGAIN THIS EVENING AND INTO SATURDAY MORNING WHEN
WE HAVE LOW PROBABILITY OF SEEING CEILINGS LOWER TO LIFR, GREATEST
POTENTIAL OVER THE NORTH BAY AND MONTEREY BAY TERMINALS.
VICINITY OF SFO...HIGH CONFIDENCE FOR MVFR CEILINGS TO SCATTER OUT
AND/OR CLEAR BY 18Z-19Z WITH ONSHORE WINDS INCREASING THIS
AFTERNOON. HIGH CONFIDENCE FOR MVFR CEILINGS TO RETURN LATE THIS
EVENING WITH THE LOW CONFIDENCE FOR IFR CEILINGS AS WE HEAD INTO
EARLY SATURDAY MORNING. EXPECTING LOW CLOUDS TO DIMINISH A BIT LATER
TOMORROW BETWEEN 19Z-20Z AS THE MARINE LAYER IS FORECAST TO COMPRESS
SLIGHTLY. ONCE LOW CLOUDS CLEAR, LOOK FOR AN INCREASE IN ONSHORE
WINDS ONCE AGAIN.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR/MVFR CEILINGS CURRENTLY AT THE TAF
SITES BUT CLEARING SHOULD OCCUR SOON AT SNS. MRY LOOKS TO SEE MVFR
CEILINGS THROUGH ABOUT 21Z, YET MAY LINGER THROUGH A GOOD PORTION OF
THE DAY. HIGH CONFIDENCE FOR IFR/MVFR CEILINGS TO MAKE AN EARLY
RETURN THIS EVENING WITH A LOW PROBABILITY OF LIFR CONDITIONS HEADING
INTO SATURDAY MORNING.
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 1033 AM PDT FRI JUL 18 2025
LIGHT TO MODERATE WEST OR NORTHWEST BREEZES CONTINUE ACROSS THE
MAJORITY OF THE COASTAL WATERS THROUGH THIS WEEKEND WITH WINDS
EASING INTO THE UPCOMING WEEK. GUSTY WINDS, POTENTIALLY HAZARDOUS
TO SMALL CRAFT, DEVELOP EACH AFTERNOON AND EVENING THROUGH THE
GOLDEN GATE, INTO THE DELTA, AND THE FAVORED COASTAL JETS OFF OF
PIGEON POINT AND 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.
UPDATE...KENNEDY
SHORT TERM...MM
LONG TERM....MM
AVIATION...RGASS
MARINE...RGASS
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