411
FXUS66 KMTR 101818
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1118 AM PDT SUN AUG 10 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 200 AM PDT SUN AUG 10 2025
- MODERATE HEATRISK CONTINUES THROUGH MONDAY FOR PORTIONS OF NORTH,
EAST, AND SOUTH BAY COUNTIES AND INTERIOR MONTEREY AND SAN BENITO
COUNTIES.
- ELEVATED FIRE WEATHER CONCERNS PERSIST GIVEN THE WARM AND DRY
CONDITIONS, WITH BREEZY WINDS EACH AFTERNOON AND EVENING.
- PATTERN CHANGE TUESDAY, WITH COOLER WEATHER AND COASTAL DRIZZLE
RETURNING TO THE FORECAST.
UPDATE
ISSUED AT 906 AM PDT SUN AUG 10 2025
SATELLITE IMAGERY SHOWS STRATUS MIXING OUT ACROSS THE COASTAL
VALLEYS, WITH HIGH-LEVEL SMOKE FROM THE GIFFORD FIRE DRIFTING
NORTHWARD THROUGH THE CENTRAL COAST AND THE BAY AREA. PATCHY DENSE
FOG WAS REPORTED EARLIER THIS MORNING, WITH MORE RECENT REPORTS
SHOWING CONDITIONS IMPROVING ACROSS THE REGION. OTHERWISE, THE
FORECAST REMAINS UNCHANGED WITH HOT AND DRY CONDITIONS BEING THE
MAIN AREA OF FOCUS FOR THE NEXT COUPLE OF DAYS.
DIALH
SHORT TERM
ISSUED AT 200 AM PDT SUN AUG 10 2025
(TODAY AND TONIGHT)
STARTING ANOTHER FORECAST DISCUSSION, WITH YOU GUESSED IT, SATELLITE
OBSERVATION! THE PICTURE FROM SPACE SHOWS THE STRATUS HAS SPREAD
SUBSTANTIALLY FARTHER INLAND, INFILTRATING PORTIONS OF THE NORTH,
EAST, AND SOUTH BAY REGIONS AND A GOOD PORTION OF THE CENTRAL COAST.
STRATUS WILL CONTINUE TO SNAKE IT'S WAY INTO THE REGION THIS MORNING,
BEFORE QUICKLY RETREATING BACK TO THE COAST AFTER SUNRISE. IT'S
ANOTHER, WASH, RINSE, REPEAT FORECAST! SUNNY SKIES AND SUMMER HEAT
RETURNS FOR INTERIOR LOCATIONS, AS TEMPERATURES RISE INTO THE LOW
90S TO NEAR 103. IF YOU PLAN ON BEING OUTDOORS IN THIS HEAT, WHETHER
FOR WORK OR FOR PLAY, PLEASE CONSIDER TAKING SOME HEAT SAFETY
ACTIONS. CONSIDER WEARING SUNSCREEN, TAKING BREAKS, STAYING
HYDRATED, REDUCING YOUR TIME OUTDOORS, OR WEARING LIGHTER AND/OR
LOOSER FITTED CLOTHING.
LONG TERM
ISSUED AT 200 AM PDT SUN AUG 10 2025
(MONDAY THROUGH SATURDAY)
WARMER INLAND WEATHER CONTINUES THROUGH MONDAY, WITH A PATTER CHANGE
BEGINNING ON TUESDAY. UPPER LEVEL RIDGING BREAKS DOWN AS AN UPPER
LEVEL TROUGH MOVES INTO THE PACNW. WIDESPREAD COOLING IS EXPECTED BY
WEDNESDAY AND WILL CONTINUE THROUGH FRIDAY, MODERATING SOME BY THE
WEEKEND. TROUGHING WILL LEAD TO WIDESPREAD STRATUS AND DRIZZLE
DURING THE OVERNIGHT AND EARLY MORNING HOURS.
AVIATION
(18Z TAFS)
ISSUED AT 1118 AM PDT SUN AUG 10 2025
THE MARINE LAYER REMAINS NEAR 1300 FEET DEEP WITH A STRONG LOWER
LEVEL TEMPERATURE INVERSION PRESENT UNDER HIGH PRESSURE ALOFT. THE
MORNING 12Z OAKLAND UPPER AIR SOUNDING MANDATORY PRESSURE LEVEL
TEMPS AT 925 MB, 850 MB, 700 MB AND 500 MB WERE 90TH-95TH PERCENTILE
FOR EARLY-MID AUGUST. MID TO UPPER LEVEL THERMAL AND HEIGHT RIDGING
REMAINS STEADY TODAY, TONIGHT AND MONDAY HOWEVER THE NAM DOES
FORECAST NEAR SURFACE COOLER AIR TO UNDERCUT THE THERMAL AND HEIGHT
RIDGE ALOFT BY MONDAY MORNING. HREF IFR/MVFR PROBABILITIES SHOWS
SOMEWHAT MORE OF A LEADING EDGE OF STRATUS REACHING THROUGH THE
DELTA MONDAY MORNING. AT THE AIR/SEA INTERFACE CONDITIONS ARE
FAVORABLE FOR STRATUS AND FOG, ONSHORE WINDS USHERING IN STRATUS
AND FOG /MVFR-IFR-LIFR/ TONIGHT AND MONDAY MORNING. PATCHY COASTAL
DRIZZLE ALSO DEVELOPING IN THE COOLER NEAR SURFACE AIR MASS
TONIGHT AND MONDAY MORNING WITH GENTLE UPSLOPING ALONG THE COASTAL
TERRAIN. STRATUS AND FOG THEN MIXING OUT BY LATE MONDAY MORNING,
INCREASINGLY VFR CONDITIONS REDEVELOPING MONDAY AFTERNOON.
WILDFIRE SMOKE ALOFT IS ALSO IN THE MIX TODAY, TONIGHT AND MONDAY
PER RECENT HRRR SMOKE MODEL FORECASTS. SMOKE ALOFT LIKELY REDUCING
SLANT RANGE VISIBILITY ESPECIALLY NEAR SUNSET AND SUNRISE.
VICINITY OF SFO...VFR HAS SOLIDLY RETURNED NOW, THERE WAS AN AREA
OF STRATUS OVER THE SF BAY, HOWEVER THAT HAS MOSTLY MIXED OUT.
HIGH CONFIDENCE VFR FORECAST FOR THE REMAINDER OF THE DAY TO EARLY
TO MID EVENING, STRATUS /MVFR/ RETURNING 10Z MONDAY MORNING. STRATUS
MIXES OUT BY 17Z MONDAY. LIGHT NORTHEAST WIND SHIFTING TO WESTERLY
AND INCREASING TO 15 KNOTS THIS AFTERNOON TO EARLY EVENING. WEST
TO NORTHWEST WIND NEAR 10 KNOTS TONIGHT AND MONDAY MORNING, INCREASING
FROM THE WEST 15 TO 20 KNOTS MONDAY AFTERNOON.
SFO BRIDGE APPROACH...REDUCED SLANT RANGE VISIBILITY MAINLY NEAR
SUNSET AND SUNRISE DUE TO WILDFIRE SMOKE ALOFT. OTHERWISE SIMILAR
TO SFO.
MONTEREY BAY TERMINALS...DIURNAL MIXING IS DECREASING THE AREAL
STRATUS COVERAGE LATE THIS MORNING. IT'S A NEAR HIGH CONFIDENCE
VFR FORECAST FOR THE AFTERNOON AND EARLY EVENING, THEN STRATUS,
FOG AND PATCHY DRIZZLE /IFR-LIFR/ DEVELOP TONIGHT AND MONDAY
MORNING. CONDITIONS IMPROVE TO MVFR-VFR BY LATE MONDAY MORNING,
WITH VFR MONDAY AFTERNOON. MAINLY WEST TO NORTHWEST WINDS 5 TO 15
KNOTS.
MARINE
(TODAY THROUGH FRIDAY)
ISSUED AT 906 AM PDT SUN AUG 10 2025
A GENTLE TO MODERATE BREEZE AND MODERATE SEAS WILL PREVAIL THROUGH
TUESDAY WITH DIURNALLY DRIVEN AFTERNOON SEA BREEZE GUSTS UP TO 25
KNOTS THROUGH THE DELTA. WINDS INCREASE AND SEAS BUILD WEDNESDAY
WITH FRESH TO STRONG NORTHWESTERLY BREEZES AND ROUGH SEAS ON TAP
FOR THE OUTER WATERS AND COASTAL JET REGIONS.
FIRE WEATHER
ISSUED AT 906 AM PDT SUN AUG 10 2025
NOT MUCH CHANGE TO THE FORECAST FOR THE NEXT COUPLE OF DAYS, WITH
HOT AND DRY CONDITIONS PERSISTING THROUGH MONDAY AND BREEZY AND
GUSTY ONSHORE WINDS EACH AFTERNOON AND EVENING, BOTH LEADING TO
CURING FUELS AND THE POSSIBILITY OF RAPIDLY SPREADING FIRES SHOULD
ONE START. POOR OVERNIGHT HUMIDITY RECOVERIES IN THE HIGHER
TERRAIN WILL CONTRIBUTE TO THE FIRE WEATHER THREATS. AS AN UPPER
LEVEL RIDGE BREAKS DOWN, THE GUSTY AFTERNOON WINDS WILL LINGER,
POSSIBLE THROUGH THE MIDDLE OF THE UPCOMING WORK WEEK. HOWEVER,
THE COOLING TEMPERATURES AND DEEPENING MARINE LAYER WILL HELP TO
MITIGATE FIRE WEATHER THREATS, AND BY THE END OF THE WORK WEEK A
TROUGH SHOULD BRING TEMPERATURES BELOW SEASONAL AVERAGES ACROSS
THE REGION.
DIALH
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR SF BAY N
OF BAY BRIDGE.
SHORT TERM...KR
LONG TERM....KR
AVIATION...CANEPA
MARINE...CANEPA
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