429
FXUS66 KMTR 110024
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
524 PM PDT THU JUL 10 2025
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1208 PM PDT THU JUL 10 2025
- INLAND TEMPERATURES ROUGHLY 10 DEGREES WARMER THAN YESTERDAY,
BRINGING MODERATE HEATRISK THROUGH FRIDAY.
- LOCALIZED ELEVATED FIRE WEATHER THREAT CONTINUES ACROSS HIGHER
ELEVATIONS.
- GRADUAL COOLING TREND NEXT WEEK.
SHORT TERM
ISSUED AT 1208 PM PDT THU JUL 10 2025
(THIS EVENING THROUGH FRIDAY)
BYRON AIRPORT IN FAR EASTERN CONTRA COSTA COUNTY CROSSED INTO THE
90S BY NOON, BUT MOST INLAND STATIONS ARE STILL REPORTING 70S AND
LOW 80S. SOME SMOKE IS PROPAGATING INTO THE REGION, MAINLY FROM
THE GREEN FIRE IN SHASTA COUNTY. THIS WILL FILTER AND REFLECT SOME
OF THE SUNLIGHT AND SHOULD TAKE THE EDGE OFF THE HEAT TODAY. OUR
LATEST SHORT TERM FORECAST KEEPS THE WARMEST AREAS GENERALLY IN
THE MID 90S BOTH TODAY AND FRIDAY. WHILE THESE TEMPERATURES ARE
ONLY 5-10 DEGREES ABOVE NORMAL, IT MAY FEEL WORSE THAN THAT SINCE
WE JUST FINISHED A COOL PERIOD. COASTAL AREAS WILL STAY IN THE 60S
AND 70S THANKS TO ONSHORE WIND. THE MARINE LAYER HAS COMPRESSED
TO 1,000 FEET, WHICH WILL KEEP OVERNIGHT CLOUDS CONFINED CLOSER TO
THE COAST AND THEY SHOULD EVAPORATE FASTER THAN NORMAL FRIDAY
MORNING.
LONG TERM
ISSUED AT 1208 PM PDT THU JUL 10 2025
(FRIDAY NIGHT THROUGH NEXT WEDNESDAY)
THERE IS HIGH CONFIDENCE THAT THE PATTERN WILL REMAIN FAIRLY
STABLE THROUGH EARLY NEXT WEEK WITH HIGH PRESSURE ANCHORED NEAR
THE CHANNEL ISLANDS, EMBEDDED IN BROAD HIGH PRESSURE ACROSS THE
EASTERN PACIFIC. WHILE THIS HIGH PRESSURE WILL CAUSE THE 850 TEMP
TO BUILD TO THE 90TH PERCENTILE FOR MID-JULY, WE ARE ACTUALLY
GOING TO COOL OFF A BIT THIS WEEKEND. THE OVERALL PATTERN SUPPORTS
ONSHORE WIND. WITH HIGH PRESSURE OFFSHORE AND TO OUR SOUTH, BOTH
DOWNGRADIENT AND GEOSTROPHIC WINDS ARE ONSHORE. THIS SYNOPTIC
FORCING IS ENHANCED EACH DAY AS THE THERMAL TROUGH OVER THE
CENTRAL VALLEY DEEPENS. THE PRESSURE GRADIENT FROM SFO TO SAC IS
EXPECTED TO FLUCTUATE FROM +1 MB AT NIGHT TO +4 MB DURING THE DAY
THROUGH EARLY NEXT WEEK. THIS HAPPENS BECAUSE THE RIDGE BRINGS
AFTERNOON TEMPERATURES AROUND 100 DEGREES IN THE CENTRAL VALLEY.
THIS HOT AIR RISES AND LITERALLY LIFTS A WEIGHT OFF THE LOWER
ATMOSPHERE. THIS INDUCED LOW PRESSURE THEN PULLS IN AIR FROM THE
BAY AREA LIKE A VACUUM. WITH OCEAN WATERS IN THE MID-50S, THE
ONSHORE WINDS ACT AS A NATURAL AIR CONDITIONING, KEEPING US MUCH
COOLER. BY THE MIDDLE OF NEXT WEEK, IT LOOKS LIKE A TROUGH WILL
DISRUPT THE PATTERN AND COOL THINGS OFF ACROSS THE STATE. IN THE
SUPER-LONG RANGE, THERE IS SOME INDICATION THAT A 4-CORNERS HIGH
WILL START TO BUILD AROUND JULY 22-24, WHICH COULD BRING MORE
IMPACTFUL HEAT LATE IN THE MONTH.
AVIATION
(00Z TAFS)
ISSUED AT 522 PM PDT THU JUL 10 2025
IFR AND LIFR CIGS ARE BUILDING ALONG THE COAST AND ARE AFFECTING
HAF. EXPECT WINDS TO REDUCE INTO THE EVENING AND BECOME LIGHT FOR
MOST AREAS. IFR CIGS ARRIVE TO THE MONTEREY BAY TERMINALS IN THE MID
EVENING AND FALL TO LIFR INTO THE NIGHT WITH MIST AND DRIZZLE
AFFECTING THE IMMEDIATE COAST AND SLIGHTLY INLAND TERMINALS. IFR CIGS
ARRIVE AT APC IN THE LATE NIGHT AND LIFR CIGS AND FOG AFFECT STS
INTO THE MORNING. INCONSISTENT IFR CIGS WILL MOVE AROUND THE SF BAY
IN THE LATE NIGHT AND INTO FRIDAY MORNING, AFFECTING SFO AND OAK.
FOG WILL ALSO FORM AROUND THE MRY INTO FRIDAY MORNING.CLEARING
BEGINS IN THE MID MORNING WITH MOST TAF SITES GOING VFR IN THE MID
TO LATE MORNING. THE EXCEPTION WILL BE HAF, WHICH KEEPS CIGS THROUGH
THE TAF PERIOD. WINDS LOOK TO STAY LIGHT TO MODERATE THROUGH MUCH OF
THE MORNING, BUT WILL INCREASE INTO THE LATE MORNING MORNING AND
AFTERNOON. EXPECT WINDS TO REDUCE INTO FRIDAY EVENING.
VICINITY OF SFO...VFR LASTS THROUGH THE LATE NIGHT. WINDS STAY
BREEZY INTO THE LATE EVENING BEFORE BECOMING LIGHT TO MODERATE. IFR-
LEVEL CLOUDS SHIFT THROUGH THE SF BAY IN THE LATE NIGHT, AND LOOK TO
INCONSISTENTLY FILL OVER SFO AND OAK BEFORE EXITING INTO EARLY
FRIDAY. BREEZY WEST WINDS RETURN IN THE LATE MORNING, AND LOOK TO
LAST THROUGH THE MID EVENING BEFORE BECOMING LIGHT AGAIN.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...IFR CIGS ARE BUILDING IN THE BAY AND LOOK
TO FILL OVER THE TERMINALS AS WINDS REDUCE INTO THE EVENING. LIGHT
WINDS LAST THROUGH THE NIGHT WITH CIGS FALLING TO LIFR AND POCKETS
OF MIST AND DRIZZLE AFFECTING VISIBILITIES INTO THE MID MORNING
MORNING. MOMENTS OF FOG ALSO LOOK TO AFFECT MRY. WINDS BECOME
MODERATE INTO MID FRIDAY MORNING AS CIGS ERODE OVER THE TERMINALS,
BUT EXPECT CLOUD COVER TO LINGER OVER THE MONTEREY BAY ITSELF UNTIL
THE MID AFTERNOON.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 522 PM PDT THU JUL 10 2025
STRONG NORTHERLY BREEZES OVER THE OUTER WATERS WILL CONTINUE
THROUGH SATURDAY WITH THE MOST HAZARDOUS CONDITIONS IN THE FAR
NORTHWESTERN PORTION WITH GALE FORCE GUSTS AND VERY ROUGH SEAS.
SUNDAY AND MONDAY WILL HAVE A GENTLE BREEZE WITH MODERATE TO
ROUGH SEAS.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 AM PDT FRIDAY FOR PT ARENA TO PT
REYES 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR PT PINOS TO
PT PIEDRAS BLANCAS 0-10 NM.
GALE WARNING UNTIL 9 AM PDT FRIDAY FOR PT ARENA TO PT REYES 10-
60 NM.
SMALL CRAFT ADVISORY UNTIL 9 AM PDT FRIDAY FOR PIGEON PT TO PT
PINOS 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...MURDOCK
MARINE...SARMENT
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