322
FXUS66 KMTR 171744
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1044 AM PDT THU JUL 17 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 235 AM PDT THU JUL 17 2025
- BELOW SEASONAL TEMPERATURES CONTINUE THROUGH THURSDAY BEFORE A
SLIGHT WARMING TREND BEGINS FRIDAY INTO THE WEEKEND.
- LOCALIZED ELEVATED FIRE WEATHER THREAT CONTINUES ACROSS THE
HIGHER ELEVATIONS WITH DRIER CONDITIONS BEGINNING THIS WEEKEND.
- INCREASING WINDS EARLY NEXT WEEK.
UPDATE
ISSUED AT 858 AM PDT THU JUL 17 2025
ANOTHER COOL START TO THE MORNING WITH MOST LOCATIONS ACROSS THE
REGION IN THE 50S TO 60S THIS MORNING. THE 12Z OAK SOUNDING SHOWS
THE MARINE LAYER IS STILL AROUND 2000 FEET WITH WIDESPREAD STRATUS
ACROSS THE BAY AREA AND CENTRAL COAST. THE MARINE LAYER WILL START
TO COMPRESS TONIGHT WITH COASTAL DRIZZLE CHANCES BECOMING MORE
LIMITED FRIDAY MORNING. TEMPERATURES REMAIN BELOW NORMAL TODAY
BEFORE A SLIGHT WARMING TREND BEGINS TOMORROW. NO MAJOR CHANGES TO
THE OVERALL FORECAST, THE WARMING TREND WILL BRING BACK MORE
SEASONAL TEMPERATURES WITH HIGH TEMPERATURES PEAKING ON SUNDAY IN
THE 80S TO LOW 90S ACROSS THE INTERIOR. CONFIDENCE CONTINUES TO GROW
THAT BELOW NORMAL TEMPERATURES WILL RETURN MONDAY AS ANOTHER UPPER
SHORT TERM
ISSUED AT 240 AM PDT THU JUL 17 2025
(TODAY AND TONIGHT)
WE'RE MORE THAN HALFWAY THROUGH THE MONTH AND "NO SKY JULY"
REMAINS LOCKED IN. CURRENT OVERNIGHT SATELLITE FOG PRODUCT SHOWS
ANOTHER ROBUST MARINE LAYER BLANKETING THE COASTAL WATERS AND
INLAND VALLEYS. FORT ORD PROFILER INDICATES THE DEPTH OF THE
MARINE LAYER ACTUALLY INCREASING A LITTLE SINCE WEDNESDAY. THE
SLIGHT DEEPENING IS LIKELY DUE TO A WEAK/SUBTLE UPPER LEVEL
SHORTWAVE TROUGH OVER NORCAL COAST. THE DEEPER MARINE LAYER WAS
JUST ENOUGH TO HAMPER ANOTHER "DRIZZLE-FEST" ALONG THE COAST.
WE'VE HAD ONE GAGE TIP SINCE MIDNIGHT, WHICH IS LESS THAN 24
HOURS AGO. THAT BEING SAID, WILL STILL CARRY SOME PATCHY DRIZZLE
IN THE FORECAST FOR THE COAST THURSDAY MORNING. MORNING CLOUDS
WILL GIVE WAY TO INLAND SUNSHINE. DESPITE SOME INLAND SUNSHINE
TEMPERATURES WILL STILL BE SEASONABLY COOL FOR JULY WITH HIGHS
REACHING THE UPPER 50S TO NEAR 70 FOR THE COAST AND 60S TO LOWER
90S INLAND -- OR ABOUT 5 TO 10 DEGREES BELOW NORMAL FOR JULY.
SPEAKING OF BELOW NORMAL - JULY 1 THROUGH JULY 16 HAS SHOWN HIGH
TEMPERATURES ON AVERAGE ARE 1 TO 3 DEGREES BELOW NORMAL. WHO
REMEMBERS JULY OF 2024? IF YOU DO, IT WAS SO MUCH WARMER THAN
2025. TEMPERATURES ON AVERAGE FOR THE WHOLE MONTH OF JULY WERE 2
TO 4 DEGREES WARMER THAN AVERAGE WITH INLAND AREAS 6 TO 8 DEGREES
WARMER.
EXPECT SIMILAR CONDITIONS AGAIN THURSDAY NIGHT INTO FRIDAY - SOLID
MARINE LAYER WITH SOME PATCHY COASTAL DRIZZLE.
PREVIOUS DISCUSSION HIGHLIGHTED FIRE WEATHER CONCERNS ABOVE THE
MARINE LAYER AND THOSE CONCERNS REMAIN EARLY THURSDAY MORNING.
DRY AND MILD CONDITIONS REMAIN AT 2000 FEET AND ABOVE WITH
TEMPERATURES IN THE 60S TO LOWER 70S WITH POOR HUMIDITY LESS THAN
30%.
LONG TERM
ISSUED AT 328 AM PDT THU JUL 17 2025
(FRIDAY THROUGH WEDNESDAY)
WHILE WE'RE TALKING ABOUT SEASONABLY COOL JULY SO FAR WE WILL SEE
SOME WARMING IN THE LONG TERM. INTERESTING LONGWAVE PATTERN OVER
CA FRIDAY AND INTO THE WEEKEND. TWO UPPER LOWS CONTINUE TO SPIN
WITH ONE RETROGRADING OFF THE NORCAL COAST AND THE OTHER IS MOVE
THROUGH N BAJA/SOCAL. IN BETWEEN IS A SQUEEZED UPPER LEVEL RIDGE.
THIS RIDGE WILL RESULT IN HIGHER 500MB HEIGHTS, WARMER 850MB
TEMPS, AND A SLIGHTLY MORE COMPRESSED MARINE LAYER. AS SUCH, A
SLIGHT UPTICK IN TEMPERATURES CAN BE EXPECTED FRIDAY AND OVER THE
WEEKEND. TEMPERATURES THROUGH THIS PERIOD WILL WARM 3 TO 5
DEGREES EACH DAY WITH FAR INLAND AREAS REACHING THE MID TO UPPER
90S. DAYTIME TEMPERATURES WILL WARM, BUT OVERNIGHT WILL SEE SOME
RELIEF LIMITING HEATRISK IMPACTS FOR THE REGION.
THE WARM UP COMES TO AN END EARLY NEXT WEEK AS ANOTHER UPPER LEVEL
TROUGH/LOW TAKES AIM AT NORCAL. EXPECT THE MARINE LAYER TO DEEPEN
ONCE AGAIN. ONE OTHER FALL OUT FROM THE TROUGH WILL BE INCREASING
NORTHERLY WINDS. COOL AND WINDER CONDITIONS WILL LINGER THROUGH AT
LEAST WEDNESDAY.
AVIATION
(18Z TAFS)
ISSUED AT 1042 AM PDT THU JUL 17 2025
GENERALLY MVFR WHERE LOW CLOUDS PERSIST THIS MORNING WHILE INLAND
AREAS CONTINUE TO CLEAR OUT. THE REMAINDER OF THE TAF SITES WILL
CLEAR OUT BETWEEN 18Z-20Z, WITH THE EXCEPTION OF HAF WHERE LOW
CEILINGS MAY PERSIST THROUGH MUCH OF THE DAY. ONSHORE WINDS INCREASE
THIS AFTERNOON BEFORE EASING AFTER SUNSET. HIGH CONFIDENCE FOR
IFR/MVFR CEILINGS TO RETURN EITHER BY LATE THIS EVENING ACROSS THE
MONTEREY BAY TERMINALS AND THEN EARLY FRIDAY MORNING FOR BAY AREA
TERMINALS. CEILINGS WILL BEGIN TO LIFT AROUND 18Z-20Z FRIDAY FOR
INLAND AREAS WITH ANOTHER INCREASE IN ONSHORE WINDS BY FRIDAY
AFTERNOON.
VICINITY OF SFO...MVFR CURRENTLY WITH CONDITIONS EXPECTED TO RETURN
TO VFR BETWEEN 18Z-20Z. WESTERLY TO NORTHWESTERLY WINDS INCREASE
THIS AFTERNOON BEFORE EASING LATE IN THE NIGHT. HIGH CONFIDENCE FOR
MVFR CEILINGS TO RETURN BY EARLY FRIDAY MORNING AND WILL PERSIST
THROUGH ABOUT 18Z-20Z FRIDAY.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...MVFR CURRENTLY WITH CLEARING CONDITIONS
BETWEEN 18Z-20Z. HOWEVER, MODERATE CONFIDENCE FOR CLEARING TO OCCUR
WITH LOW HIGH CONFIDENCE FOR IFR/MVFR CEILINGS TO RETURN THIS
EVENING. ONSHORE WINDS WILL INCREASE THIS AFTERNOON BEFORE EASING
AFTER SUNSET. LIFR CONDITIONS WILL BE POSSIBLE ACROSS THE TERMINALS
EARLY FRIDAY MORNING BEFORE LIFTING BY LATE MORNING.
MARINE
(TODAY THROUGH TUESDAY)
ISSUED AT 1042 AM PDT THU JUL 17 2025
EXPECT A LIGHT TO MODERATE WESTERLY OR NORTHWESTERLY BREEZE
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 JETS ALONG PIGEON POINT AND BIG
SUR. MODERATE SEAS ALSO CONTINUE THROUGH THE REMAINDER OF THE
FORECAST PERIOD.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 9 AM TO 9 PM PDT FRIDAY FOR SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 3 PM TO 9 PM PDT FRIDAY FOR PIGEON PT
TO PT PINOS 0-10 NM.
SMALL CRAFT ADVISORY FROM 3 PM FRIDAY TO 3 AM 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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