182
FXUS66 KMTR 180449
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
949 PM PDT THU JUL 17 2025
..NEW AVIATION
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 830 PM PDT THU JUL 17 2025
SATELLITE IMAGERY SHOWS COASTAL STRATUS EXPANDING INTO THE NORTH
BAY VALLEYS, THE BERKELEY HILLS, AND THE MONTEREY BAY REGION,
WITH FURTHER INLAND DEVELOPMENT EXPECTED THROUGH THE NIGHT. THE
FORECAST REMAINS ON TRACK FOR WARMER TEMPERATURES FRIDAY INTO THE
WEEKEND WITH NO CHANGES NECESSARY.
DIALH
SHORT TERM
ISSUED AT 155 PM PDT THU JUL 17 2025
(THIS EVENING THROUGH FRIDAY)
THE MARINE LAYER WILL START TO COMPRESS TONIGHT AS TROUGHING OVER
THE WEST COAST IS PUSHED NORTHWARD OVER OR/WA BY WEAK HIGH PRESSURE
BUILDING IN OVER CALIFORNIA. GUIDANCE SHOWS HIGH PRESSURE BUILDING
MORE SLOWLY THROUGHOUT THE DAY WITH FRIDAY ACTING AS MORE OF A
TRANSITION DAY FROM WEAK/SUBTLE TROUGHING TO WEAK HIGH PRESSURE. THE
MAIN CHANGE TO THE FORECAST IS HOW MUCH TEMPERATURES WILL WARM.
TEMPERATURES ACROSS THE BOARD WILL WARM BETWEEN 1 TO 5 DEGREES ON
FRIDAY. FOR THE LOWER ELEVATIONS, THIS PUSHES MOST SITES CLOSER TO
SEASONAL AVERAGES, BUT, MOST WILL REMAIN AT LEAST SLIGHTLY COOLER
THAN NORMAL. ACROSS THE HIGHER ELEVATIONS, TEMPERATURES HAVE BEEN
CLOSER TO SEASONAL AVERAGES SO THIS SLIGHT WARM UP WILL PUSH
TEMPERATURES TO SEASONAL TO SLIGHTLY ABOVE NORMAL. WHAT SPECIFICALLY
DOES THAT MEAN FOR TOMORROWS HIGH TEMPERATURES? AREAS CLOSER TO THE
SF BAY SHORELINE WILL ONLY WARM 2-3 DEGREES WITH HIGHS IN THE MID TO
UPPER 70S WHILE AREAS AWAY FROM THE BAY SHORELINE WILL BE IN THE
UPPER 70S TO 80S. RESIDENTS OF INTERIOR MONTEREY AND SAN BENITO
COUNTIES MAY FEEL THIS WARM UP MORE THAN RESIDENTS OF THE BAY AREA
WITH HIGHS RISING FROM THE LOW TO MID/UPPER 90S. COASTAL RESIDENTS
CONTINUE TO BENEFIT FROM THE NATURAL A/C OF THE MARINE LAYER WITH
TEMPERATURES STAYING IN THE UPPER 50S TO 60S.
IN TERMS OF STRATUS AND DRIZZLE CHANCES, THE MARINE LAYER WAS AROUND
2000 FT AS OF THE 12Z OAK SOUNDING THIS MORNING. WITH HIGH PRESSURE
BUILDING IN MORE SLOWLY TOMORROW, ANOTHER NIGHT OF WIDESPREAD
STRATUS IS EXPECTED ACROSS THE BAY AREA AND CENTRAL COAST. THERE IS
SOME POTENTIAL FOR COASTAL DRIZZLE TONIGHT, BUT, THIS IS MAINLY
LIMITED TO THE COASTAL NORTH BAY WITH CHANCES DECREASING ALONG THE
REST OF THE COASTLINE.
LONG TERM
ISSUED AT 155 PM PDT THU JUL 17 2025
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
TEMPERATURES WILL BE FAIRLY SIMILAR ON SATURDAY TO THOSE OBSERVED ON
FRIDAY, UPPER 70S ALONG THE BAY SHORELINE, UPPER 70S TO 80S FARTHER
AWAY FROM THE SHORELINE, AND 90S ACROSS THE FAR INTERIOR EAST BAY
AND CENTRAL COAST REGIONS. THIS WILL KEEP US WITH SEASONAL TO
SLIGHTLY BELOW NORMAL TEMPERATURES ACROSS THE MAJORITY OF THE BAY
AREA WITH ONLY THE HIGHER ELEVATIONS SEEING SLIGHTLY ABOVE NORMAL
TEMPERATURES. TEMPERATURES WILL PEAK ON SATURDAY FOR THE INTERIOR
CENTRAL COAST BUT PEAK ON SUNDAY FOR THE BAY AREA AS HIGH PRESSURE
BECOMES MORE DOMINANT ACROSS THE REGION. THIS WILL BRING
TEMPERATURES LARGELY INTO THE 80S ACROSS THE INTERIOR AND LOW TO MID
90S ACROSS THE INTERIOR EAST BAY AND CENTRAL COAST. TEMPERATURES
COOL DOWN WELL OVERNIGHT (50S TO 60S) WITH ONLY MINOR HEATRISK
FORECAST ACROSS INTERIOR REGIONS THROUGH THE WEEKEND.
THOUGHT YOU'D SEEN THE LAST OF NO SKY JULY? NOPE. UPPER LEVEL
TROUGHING IS FORECAST TO RETURN ACROSS OUR AREA EARLY NEXT WEEK AND
CONTINUE THROUGH THE END OF THE FORECAST PERIOD. THIS WILL SEE
TEMPERATURES DROPPING BELOW NORMAL AGAIN WITH HIGH TEMPERATURES
FALLING BACK INTO THE MID 70S TO LOW 80S ACROSS THE INTERIOR.
TEMPERATURES ACROSS THE INTERIOR CENTRAL COAST WILL CONTINUE TO BE
SEASONAL TO SLIGHTLY ABOVE NORMAL IN THE UPPER 80S TO LOW 90S. THE
MARINE LAYER LOOKS TO DEEPEN AGAIN MONDAY WITH WIDESPREAD OVERCAST
CONDITIONS LIKELY TO RETURN AGAIN EACH NIGHT STARTING MONDAY. CPC
GUIDANCE INDICATES TEMPERATURES ARE LIKELY TO REMAIN BELOW NORMAL
THROUGH THE END OF JULY AS UPPER LEVEL TROUGHING CONTINUES.GUSTY
ONSHORE WINDS RETURN TO MOUNTAIN GAPS/PASSES, VALLEYS, AND ALONG
THE COAST LATE SUNDAY THROUGH MONDAY AS THE UPPER LEVEL TROUGH
APPROACHES. EFI GUIDANCE HIGHLIGHTS THE POTENTIAL FOR STRONGER
WINDS IN THE VICINITY OF THE EAST BAY HILLS AND EASTERN NAPA
COUNTY WITH THE STRONGEST WINDS EXPECTED OVER THE SACRAMENTO
VALLEY.
LOCALIZED ELEVATED FIRE WEATHER CONCERNS CONTINUE ACROSS THE HIGHER
ELEVATIONS AND INTERIOR CENTRAL COAST. SEASONAL TO SLIGHTLY ABOVE
NORMAL TEMPERATURES CONTINUE ACROSS THESE REGIONS WITH DAYTIME
HUMIDITY VALUES DROPPING AS LOW AS 15% SATURDAY AND SUNDAY. WINDS
GENERALLY REMAIN LIGHT AND ONSHORE, BUT, DIURNALLY BREEZY WINDS
GUSTING TO AROUND 30 MPH ARE EXPECTED TO DEVELOP EACH
AFTERNOON/EVENING IN THE SALINAS VALLEY. DRY CONDITIONS WILL PERSIST
THROUGH THE END OF THE FORECAST PERIOD WITH DAYTIME MINIMUM HUMIDITY
VALUES IN THE 20%-30% RANGE AS UPPER LEVEL TROUGHING RETURNS.
AVIATION
(06Z TAFS)
ISSUED AT 949 PM PDT THU JUL 17 2025
COASTAL MVFR STRATUS IS BUILDING INTO THE SONOMA COUNTY VALLEYS, THE
EAST BAY, AND THE MONTEREY BAY REGION. STRATUS IS EXPECTED TO
CONTINUE EXPANDING ACROSS THE INLAND VALLEYS TONIGHT WITH SOME
IFR CEILINGS AND LIGHT WINDS INTO FRIDAY MORNING. STRATUS WILL
RETREAT TO THE IMMEDIATE COAST THROUGH THE MORNING WITH BREEZY
ONSHORE FLOW RESUMING IN THE AFTERNOON. SOME STRATUS REDEVELOPMENT
WILL OCCUR BEFORE THE END OF THE 24 HOUR TAF PERIOD, CONTINUING
THROUGH FRIDAY NIGHT INTO SATURDAY MORNING.
VICINITY OF SFO... MODERATE TO HIGH CONFIDENCE OF VFR CONDITIONS AT
THE TERMINAL SOMETIME DURING THE NIGHT. CONFIDENCE IN TIMING IS LOW
AND DEPENDS ON THE EDGE OF THE STRATUS DECK COMING SOUTHWARD, WITH
THE COVERAGE SOMEWHAT OVERDONE IN THE HIGH RESOLUTION MODELS. BY 10Z
THE STRATUS SHOULD BE COMPLETELY COVERING THE TERMINAL AREA. STRATUS
WILL MIX OUT THROUGH FRIDAY MORNING BEFORE RETURNING LATE FRIDAY
EVENING. BREEZY WEST WINDS WILL CONTINUE TO DIMINISH OVERNIGHT, WITH
ONSHORE FLOW RESUMING AT THE TERMINAL FRIDAY AFTERNOON.
SFO BRIDGE APPROACH... SIMILAR TO SFO.
MONTEREY BAY TERMINALS... MVFR-IFR STRATUS THROUGH FRIDAY MORNING.
HIGH RESOLUTION MODELS INDICATE THAT SCATTERING COULD OCCUR RATHER
LATE IN THE MORNING, AND THAT STRATUS COULD RETURN TO THE TERMINALS
AS EARLY AS 02-03Z. LIGHT WINDS CONTINUE OVERNIGHT BEFORE BREEZY
ONSHORE FLOW RESUMES FRIDAY AFTERNOON.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 830 PM PDT THU JUL 17 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 FRIDAY TO 3 AM PDT SATURDAY FOR
PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM-SF BAY N OF BAY
BRIDGE.
SHORT TERM...KENNEDY
LONG TERM....KENNEDY
AVIATION...DIALH
MARINE...DIALH
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