453
FXUS66 KMTR 162137
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
237 PM PDT WED APR 16 2025
..NEW SHORT TERM, LONG TERM
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
(18Z TAFS)
ISSUED AT 1059 AM PDT WED APR 16 2025
A BIT OF A MIXED BAG WITH MVFR AND VFR CONDITIONS. THE NORTH BAY
SEEMS TO BE ON TRACK FOR CLEARING TO VFR CLOSE TO 20Z, MEANWHILE THE
REMAINING MVFR TERMINALS WILL SEE CLEARING AROUND 19Z. AFTER 20Z,
VFR WILL PREVAIL UNTIL TONIGHT WHERE LOW CIGS WILL REBUILD. MODELS
SHOW SOME DIFFERENCES ON CEILINGS BECOMING MVFR OR REMAINING VFR BUT
MOST MODELS SHOW HIGHER CONFIDENCE FOR NORTH BAY AND MONTEREY BAY
SEEING MVFR STARTING LATE THIS EVENING. MODERATE CONFIDENCE ON THE
REMAINING TERMINALS SEEING MVFR TONIGHT, BUT IF CEILINGS LOWER,
EXPECT VFR NEAR 18-19Z THURSDAY. MODERATE TO BREEZY ONSHORE WINDS
THIS AFTERNOON, BUT LIGHT TO MODERATE WINDS OVERNIGHT.
VICINITY OF SFO...CONDITIONS HAVE IMPROVED TO VFR. THERE IS A CHANCE
FOR MVFR CONDITIONS TO RETURN NEAR 09Z, BUT CONFIDENCE IS MODERATE, AS
SOME MODELS SHOW VFR PREVAILING THROUGH THE TAF PERIOD.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...VFR/MVFR AS SOME LOW CIGS HAVE PUSHED OVER
KSNS. EXPECT VFR NEAR 19-20Z. MVFR CONDITIONS EXPECTED TO RETURN
NEAR 09-10Z WITH CLEARING NEAR 17Z.
MARINE
(TODAY THROUGH MONDAY)
ISSUED AT 912 AM PDT WED APR 16 2025
LIGHT TO MODERATE SOUTHERLY WINDS WILL TRANSITION TO MODERATE
NORTHERLY BY MIDDAY OR SO 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. SEAS WILL BUILD OUT IN THE NORTHERN OUTER WATERS THIS
AFTERNOON THROUGH THURSDAY MORNING. OTHERWISE, SMALL 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...SO
MARINE...SO
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