140
FXUS66 KMTR 100503
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1003 PM PDT SAT AUG 9 2025
..NEW AVIATION
KEY MESSAGES
UPDATED AT 339 AM PDT SAT AUG 9 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 823 PM PDT SAT AUG 9 2025
SATELLITE IMAGERY SHOWS COASTAL STRATUS EXTENDING INTO THE SONOMA
COUNTY VALLEYS, THROUGH THE GOLDEN GATE INTO THE BERKELEY AREA,
AND INTO THE MONTEREY BAY REGION AND STARTING TO GO THROUGH THE
SALINAS VALLEY. THE FORECAST REMAINS UNCHANGED WITH ANOTHER HOT
AND DRY DAY INLAND ON TAP FOR TOMORROW.
DIALH
SHORT TERM
ISSUED AT 116 PM PDT SAT AUG 9 2025
(THIS EVENING THROUGH SUNDAY)
CLASSIC SUMMER DAY ALONG THE THE CALIFORNIA COAST, COASTAL STRATUS
WITH ABUNDANT INLAND SUNSHINE. THE STRATUS DECK ALONG THE COAST
HAS A SOUTHERLY SURGE KIND OF VIBE TO IT WITH WEAK SOUTHERLY
FLOW AND UPSTREAM/DOWNSLOPE CLEARING (MONTEREY AND N OF PT
REYES). LET'S TALK ABOUT THE INLAND SUNSHINE. WE'VE BEEN MESSAGING
A SOLID WARM UP ACROSS THE INTERIOR AND IT HAS FINALLY ARRIVED. A
QUICK PULSE CHECK OF AFTERNOON TEMPS SHOW INTERIOR LOCATIONS
MAKING A SOLID RUN AT BREAKING 100 DEGREES. PARKFIELD REACHED 101
AND BRADLEY AND POPE VALLEY BOTH REACHED 100. IF YOU HAVE OUTDOOR
PLANS AND YOU'RE IN THE INTERIOR PLEASE BE SAFE AND TAKE
APPROPRIATE HEAT SAFETY ACTIONS.
TONIGHT THROUGH SUNDAY - LET'S PUT IT ON RINSE AND REPEAT.
SHALLOW MARINE LAYER WILL MOVE INLAND AGAIN. IMPACTS WILL BE
FOG/PATCHY DRIZZLE. ONCE THE MARINE LAYER ROLLS BACK TO THE COAST
SUNDAY AFTERNOON INTERIOR LOCATIONS WILL ONCE AGAIN SOAR INTO THE
LOW 90S TO 100S.
LONG TERM
ISSUED AT 135 PM PDT SAT AUG 9 2025
(SUNDAY NIGHT THROUGH NEXT FRIDAY)
MORE OF THE SAME IS EXPECTED AS WE HEAD INTO MONDAY: COASTAL
CLOUDS WITH INLAND HEAT.
IT'S NOT UNTIL TUESDAY DO WE FINALLY SEE A BREAK IN THE INLAND
HEAT. TUESDAY WILL BE A TRANSITION TOWARD A COOLDOWN AS THE RIDGE
BREAKS DOWN AND IS REPLACED BY A TROUGH OVER THE PACNW AND THE
WEST COAST. ANOTHER TROUGH, THAT SEEMS TO BE A THEME THIS SUMMER.
WIDESPREAD COOLING IS EXPECTED BY WEDNESDAY AND LAST INTO FRIDAY.
THE DEVELOPING TROUGH WILL ALSO BRING A RETURN OF MORE WIDESPREAD
DRIZZLE...SOME GUIDANCE EVEN SUGGESTS IT COULD BE ACCUMULATING
DRIZZLE.
AVIATION
(06Z TAFS)
ISSUED AT 1002 PM PDT SAT AUG 9 2025
IFR-LIFR CONDITIONS EXPECTED TONIGHT WITH DECREASES IN VISIBILITY
POSSIBLE OVERNIGHT. SOME POTENTIAL FOR FOG AT STS, HAF, MRY, AND SNS
DURING THE EARLY MORNING HOURS WITH HIGHEST CONFIDENCE IMPACTING STS
AFTER 13Z. STRATUS LOOKS TO PUSH INTO SJC LATER TONIGHT BUT IS NOT
ANTICIPATED TO REACH LVK. STRATUS COVERAGE IS EXPECTED TO DISSIPATE
BY MID TO LATE MORNING WITH VFR TO PREVAIL THROUGH THE REMAINDER OF
THE AFTERNOON. CONFIDENCE IS LOW THAT HAF WILL CLEAR BUT SOME
GUIDANCE INDICATES A BRIEF PERIOD OF CLEARING FROM ~20Z-00Z IS
POSSIBLE. IFR-LIFR CONDITIONS RETURN DURING THE EARLY EVENING ALONG
THE COASTLINE (HAF, MRY, SNS) WITH STRATUS RETURNING TO MORE
INTERIOR SITES LATER OVERNIGHT.
VICINITY OF SFO...STRATUS IS EXPECTED TO FILL IN OVERNIGHT WITH
STRATUS LIKELY TO BE ON THE IFR-LIFR BORDER. HIGHEST CONFIDENCE IN
STRATUS PERSISTING THROUGH MID TO LATE MORNING BEFORE CLOUD COVER
DIMINISHES. SOME POTENTIAL FOR STRATUS TO RETURN AS EARLY AS 09Z
TOMORROW BUT CONFIDENCE IS SLIGHTLY HIGHER IN STRATUS RETURNING JUST
AFTER THE END OF THIS TAF PERIOD. MODERATE, BREEZY NORTHWEST WINDS
RETURN DURING THE AFTERNOON/EVENING HOURS BEFORE EASING OVERNIGHT.
SFO BRIDGE APPROACH...PATCHY STRATUS IS EXPECTED TO FILL IN OVER THE
SF BAY TONIGHT AND PERSIST THROUGH MID TO LATE MORNING.
MONTEREY BAY TERMINALS...IFR-LIFR CONDITIONS OVERNIGHT AS STRATUS
PUSHES INLAND. SOME POTENTIAL FOR FOG TO DEVELOP AT MRY AND SNS
DURING THE EARLY MORNING HOURS BUT CONFIDENCE REMAINS LOW TO
MODERATE. STRATUS COVERAGE LOOKS TO DISSIPATE BETWEEN 16Z-18Z. FOR
NOW, LEANED TOWARDS STRATUS DISSIPATING CLOSER TO 18Z GIVEN MODEL
GUIDANCE AND MORE EXTENSIVE INLAND PUSH OF STRATUS BUT WORTH NOTING
THAT UNDER A PERSISTENCE FORECAST STRATUS HAS BEEN DISSIPATING
CLOSER TO 16-17Z THE LAST TWO DAYS. STRATUS RETURNS DURING THE EARLY
EVENING HOURS WITH IFR-LIFR CONDITIONS EXPECTED.
MARINE
(TONIGHT THROUGH NEXT FRIDAY)
ISSUED AT 823 PM PDT SAT AUG 9 2025
MODERATE SEAS AND A GENTLE TO MODERATE BREEZE CONTINUE THROUGH
EARLY NEXT WEEK AS HIGH PRESSURE PREVAILS ACROSS THE MARINE
ENVIRONMENT. DIURNALLY GUSTY WINDS ARE EXPECTED TO CONTINUE THIS
WEEK ACROSS THE SAN PABLO AND SUISUN BAYS WITH GUSTS TO AROUND 25
KNOTS EACH AFTERNOON AND EVENING. WINDS INCREASE AND SEAS BUILD
LATE WEEK INTO NEXT WEEKEND AS UPPER LEVEL TROUGHING RETURNS TO
THE WESTERN UNITED STATES.
FIRE WEATHER
ISSUED AT 823 PM PDT SAT AUG 9 2025
HOT AND DRY CONDITIONS CONTINUE THROUGH MONDAY, LEADING TO
ELEVATED FIRE WEATHER THREATS ACROSS THE REGION, ESPECIALLY
ACROSS THE INTERIOR MOUNTAINS WHERE OVERNIGHT HUMIDITY RECOVERIES
REMAIN POOR. THESE HOT AND DRY CONDITIONS ARE HELPING TO FURTHER
CURE FUELS (ESPECIALLY THE FINER FUELS) ACROSS THE INTERIOR
REGIONS, SHOWN BY ERC VALUES NEARING OR EXCEEDING THE 90TH
PERCENTILE. ONSHORE WINDS GUSTING TO AROUND 30-35 MPH ARE EXPECTED
TO DEVELOP EACH AFTERNOON AND EVENING THROUGH GAPS AND PASSES,
WITHIN FAVORED VALLEYS, AND ACROSS HIGHER TERRAIN. THESE FACTORS
COULD LEAD TO FIRES THAT START WITHIN THE FINER FUELS TO SPREAD
QUICKLY.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 11 PM PDT THIS EVENING FOR SF BAY N
OF BAY BRIDGE.
SMALL CRAFT ADVISORY FROM 1 PM TO 11 PM PDT SUNDAY FOR SF BAY N
OF BAY BRIDGE.
SHORT TERM...MM
LONG TERM....MM
AVIATION...KENNEDY
MARINE...KENNEDY
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