118
FXUS66 KMTR 162325
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
425 PM PDT WED APR 16 2025
..NEW AVIATION, MARINE
SYNOPSIS
ISSUED AT 304 AM PDT WED APR 16 2025
COOLER TEMPERATURES AGAIN TODAY. OTHERWISE, DRY WEATHER IS
EXPECTED THROUGH THE FORECAST PERIOD. WARMING TREND BEGINS
TOMORROW AND CONTINUES INTO THE WEEKEND. IN TERMS OF THE ISOLATED
THUNDERSTORM THREAT FOR TODAY, DECREASED CHANCES TO 10-14% WHICH
REMOVED THAT FROM THE POINT AND CLICK. SEE DETAILS BELOW.
SHORT TERM
ISSUED AT 212 PM PDT WED APR 16 2025
(THIS EVENING THROUGH THURSDAY)
COOLER AND CLOUDY CONDITIONS EXIST OVER SAN FRANCISCO AREA AND FOR
PORTIONS OF THE NORTH BAY. THERE IS SOME THINNING OF THE CLOUDS,
BUT A SOLID FEED CONTINUES THANKS TO A WEEK CIRCULATION WEST OF PT
REYES. THE BROAD PICTURE SHOWS SOME WEAK INSTABILITY OVER THE
FORECAST AREA IN THE WAY OF AFTERNOON CUMULUS BUILD UPS OVER THE
HILLS. WHILE THE CHANCES FOR THUNDERSTORMS HAVE ALL BUT
DISAPPEARED CONVECTION IS FIRING OVER THE SIERRA. LATEST ACARS FOR
SFO AND SJC SHOW SOME MUCAPE, BUT IT'S BEING CRUSHED BY BIGGER
CIN. SOME OF THE BETTER MOISTURE/INSTABILITY IS FORECAST TO BRUSH
THE CENTRAL COAST THE NEXT 12 HOURS, BUT STILL LOOKING DRY.
FOR TONIGHT: SOME MID-HIGH LEVEL CLOUDS ARE EXPECTED TO FILTER
OVER THE REGION. LOWER AND AT THE SURFACE, A ROBUST MARINE LAYER
IS EXPECTED ONCE AGAIN WITH SOME VARIATIONS ON DEPTH FROM N TO S.
SIMILAR TO THIS MORNING ACTUALLY, HIGHER DEPTH AND CLOUD COVERAGE
FOR NORTHERN AREAS AND LESS TO THE SOUTH.
THURSDAY: CLOUDS TO START THE DAY WITH A DISCONTINUOUS MARINE
LAYER. THE LONGWAVE PATTERN SHOWS THE CUT-OFF UPPER LEVEL LOW THAT
HAS BEEN SPINNING OFF THE COAST WILL MOVE INLAND NEAR LA AS IT
TRANSITIONS TO AN OPEN WAVE. AS THIS HAPPENS, ANOTHER WOUND UP
UPPER LOW SWEEPS THROUGH THE GREAT BASIN. LOCALLY, WE'RE LOOKING
FOR A MORE DRY NORTHERLY FLOW WITH A SLIGHT WARMING TREND.
LONG TERM
ISSUED AT 212 PM PDT WED APR 16 2025
(THURSDAY NIGHT THROUGH NEXT TUESDAY)
TO ROUND OUT THE WORK WEEK AND THE START OF THE WEEKEND WE'LL SEE
A NOTABLE WARMING TREND. THE INTERIOR UPPER LOW IN THE GREAT
BASIN WILL HELP ESTABLISH A PERIOD OF OFFSHORE FLOW FRIDAY AND
SATURDAY. WHILE NOT OVERLY STRONG, IT'S ENOUGH TO ASSIST WITH
THE WARMING TREND DUE TO DOWNSLOPE FLOW. HIGH PRESSURE ALSO BEGINS
TO BUILD OVER THE PACNW AND DRIFT INTO CA. DESPITE THIS SETUP THE
MARINE LAYER WILL COMPRESS, BUT MAY NOT COMPLETELY GO AWAY.
THE WARMER WEATHER WILL HOLD INTO EARLY NEXT WITH DRY ZONAL FLOW.
TEMPERATURES FINALLY COOL MID WEEK WITH A WEAK TROUGH DEVELOPING
OVER THE WEST COAST.
AVIATION
(00Z TAFS)
ISSUED AT 425 PM PDT WED APR 16 2025
MVFR STRATUS PERSISTS OVER MUCH OF THE NORTH BAY AND THE NORTHERN
SAN FRANCISCO BAY, AS WELL AS THE SOUTHERN REACHES OF MONTEREY AND
SAN BENITO COUNTIES; VFR EVERYWHERE ELSE. STRATUS WILL BEGIN
BUILDING ACROSS THE COASTAL REGIONS THIS EVENING AND OVERNIGHT WITH
CLEARING THROUGH THURSDAY MORNING, WITH MODERATE CONFIDENCE IN
TIMING. STRATUS CLEARING IS EXPECTED TO BE MORE COMPREHENSIVE THAN
THAT SEEN TODAY, WITH THE NORTH BAY TERMINALS CLEARING OUT RATHER
LATE IN THE MORNING, COMPARED TO STS BEING WELL SOCKED IN TODAY.
BREEZY SOUTHWESTERLY ONSHORE WINDS WILL CONTINUE INTO THE EVENING,
TURNING NORTHWESTERLY BY THE TIME THEY RESUME THURSDAY AFTERNOON.
VICINITY OF SFO... CURRENTLY MVFR, MONITORING A POTENTIAL BREAK IN
THE CLOUDS FOR AT LEAST TEMPORARY CLEARING OVER THE TERMINAL.
OTHERWISE, EXPECT MVFR CEILINGS TO PERSIST OVERNIGHT AND THROUGH
LATE THURSDAY MORNING. BREEZY WEST WINDS WITH GUSTS UP TO 25 KNOTS
WILL CONTINUE INTO THE EVENING, DIMINISHING OVERNIGHT BEFORE
RESUMING THURSDAY AFTERNOON.
SFO BRIDGE APPROACH... LESS CONFIDENCE IN CEILING IMPACTS FOR THE
SOUTHERN END OF THE APPROACH PATH. OTHERWISE SIMILAR TO SFO.
MONTEREY BAY TERMINALS... VFR THROUGH THE EVENING WITH BREEZY
ONSHORE WINDS DIMINISHING IN THE LATER EVENING HOURS. MVFR STRATUS
RETURNS OVERNIGHT THROUGH THURSDAY MORNING. CEILINGS MIGHT LIFT
ABOVE MVFR CRITERIA BEFORE THE SKIES FULLY CLEAR OUT EARLY THURSDAY
AFTERNOON, AS BREEZY ONSHORE WINDS RETURN.
MARINE
(TONIGHT THROUGH NEXT MONDAY)
ISSUED AT 425 PM PDT WED APR 16 2025
MODERATE NORTHERLY WINDS DOMINATE NORTH OF POINT REYES, BUT
SOUTHERLY WINDS PERSIST ELSEWHERE. NORTHERLY WINDS WILL SPREAD
THROUGH THE REST OF THE WATERS THROUGH THURSDAY AND GRADUALLY
BUILD INTO THE WEEKEND. ROUGH SEAS PERSIST IN THE NORTHERN OUTER
WATERS THROUGH THURSDAY MORNING. OTHERWISE, SLIGHT TO MODERATE
SEAS PERSIST INTO THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 3 PM PDT THURSDAY FOR PT ARENA TO PT
REYES 10-60 NM.
SHORT TERM...MM
LONG TERM....MM
AVIATION...DIALH
MARINE...DIALH
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