975
FXUS66 KMTR 180824
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
124 AM PDT FRI APR 18 2025
..NEW SYNOPSIS, SHORT TERM, LONG TERM
SYNOPSIS
ISSUED AT 1226 AM PDT FRI APR 18 2025
OVERCAST SKIES THIS MORNING WILL GRADUALLY CLEAR THROUGH THE
AFTERNOON. SLIGHTLY WARMER THAN NORMAL TEMPERATURES ARE EXPECTED
FOR INLAND AREAS THROUGH MONDAY BEFORE COOLER WEATHER RETURNS.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 1226 AM PDT FRI APR 18 2025
A DEEP MARINE LAYER PERSISTS THIS MORNING. IN FACT, THE 00Z
SOUNDING SHOWS IT WAS CLOSE TO 4,000 FEET DEEP. THAT EXPLAINS THE
EXTENSIVE CLOUD COVER SHOWN ON THE SATELLITE, HOWEVER NO
MEASURABLE DRIZZLE HAS BEEN REPORTED YET. THE MARINE LAYER WILL
GRADUALLY COMPRESS THROUGH THE DAY AS A HIGH PRESSURE RIDGE
BUILDS. THIS WILL ALLOW THE CLOUDS TO CLEAR THIS AFTERNOON. INLAND
AREAS WARM INTO THE MID 70S, OR 5-10 DEGREES WARMER THAN
YESTERDAY. COASTAL AREAS WILL STILL BE IN THE SHALLOW MARINE
LAYER, AND DESPITE THE DECREASED CLOUD COVER, TEMPERATURES WILL
STILL STAY IN THE 50S ALL DAY ALONG THE IMMEDIATE COAST. PERHAPS
THE GREATEST HAZARD IN THE SHORT TERM IS THE POTENTIAL FOR PATCHY
DENSE FOG SATURDAY MORNING DUE TO THE COMPRESSING MARINE LAYER.
LONG TERM
(SATURDAY THROUGH THURSDAY)
ISSUED AT 1226 AM PDT FRI APR 18 2025
IN THE BIG PICTURE, THE RIDGE CONTINUES THROUGH THE WEEKEND. THE
WARMER THAN AVERAGE TEMPERATURES WILL CONTINUE WITH MOSTLY GENTLE
WINDS. MOST GUIDANCE SHOWS A SMALL WEAKNESS MOVING THROUGH LATE
SATURDAY INTO SUNDAY. THIS SYSTEM WILL GO UNNOTICED BY MOST, BUT
WILL LIKELY ALLOW THE MARINE LAYER TO EXPAND FROM AROUND 500 FEET
TO 1,000 FEET, AND THE ASSOCIATED MORNING STRATUS SHOULD EXTEND A
LITTLE FURTHER INLAND. THE WEAK GRADIENT RIDGING CONTINUES INTO
EARLY NEXT WEEK AS THE 850 MB TEMPERATURE GRADUALLY RISES TO 14C,
WHICH IS AROUND THE 85TH PERCENTILE FOR THIS TIME OF YEAR. THE
WEATHER WILL STAY PRETTY CONSISTENT DURING THIS STRETCH WITH SUNNY
SKIES, MILD COASTAL TEMPERATURES IN THE LOW 60S, AND SLIGHTLY
WARMER THAN AVERAGE INLAND TEMPERATURES REACHING THE MID TO UPPER
70S. A FAIRLY SIGNIFICANT CHANGE ARRIVES ON TUESDAY AS A
POSITIVELY TILTED TROUGH USHERS IN A COOLING TREND THROUGH THE
REMAINDER OF THE WEEK. WHILE THERE IS SOME UNCERTAINTY, ROUGHLY
80% OF THE ENSEMBLE MEMBERS ARE CLUSTERED AROUND A REINFORCING
CUT-OFF LOW DEVELOPING OFF THE COAST LATE NEXT WEEK. IT'S TOO
EARLY TO SAY HOW STRONG THIS SYSTEM WILL BE, BUT WE'RE KEEPING AN
EYE ON IT MAINLY FOR A CHANCE OF LATE SEASON RAIN.
AVIATION
(06Z TAFS)
ISSUED AT 1033 PM PDT THU APR 17 2025
SCATTERED MVFR STRATUS REMAINS OVER PARTS OF THE BAY AREA WITH MORE
EXTENSIVE STRATUS COVERAGE IN THE CENTRAL COAST. STRATUS EVOLUTION
HAS BEEN DIFFICULT TO FORECAST TODAY, AND MODEL INDICATIONS ARE THAT
THE DIFFICULTY WILL CONTINUE INTO THE OVERNIGHT AND MORNING PERIODS.
THE CURRENT FORECAST CALLS FOR MVFR STRATUS TO EXPAND ACROSS THE BAY
AREA TONIGHT, WITH IFR-LIFR STRATUS POSSIBLE AT THE IMMEDIATE COAST.
STRATUS SHOULD DISSIPATE THROUGH FRIDAY MORNING, WITH LOW TO
MODERATE CONFIDENCE ON THE EXACT TIME. ALONG THE IMMEDIATE COAST,
MODELS DISAGREE ON WHETHER THERE WILL BE PERIODS OF CLEAR SKIES OR
WHETHER THE TERMINALS WILL BE SOCKED IN THROUGH THE TAF PERIOD.
BREEZY ONSHORE FLOW WILL DOMINATE FRIDAY AFTERNOON AND EVENING. A
COMPRESSING MARINE LAYER SHOULD RESULT IN LESS EXTENSIVE, BUT LOWER
CEILING, STRATUS FRIDAY NIGHT INTO SATURDAY MORNING.
VICINITY OF SFO... THE TERMINAL SHOULD REMAIN VFR THROUGH THE
EVENING HOURS AND MVFR CEILINGS WILL RETURN NEAR MIDNIGHT. CURRENT
FORECAST HAS THE CLOUDS SCATTERING OUT EARLY FRIDAY AFTERNOON WITH
BREEZY WEST-NORTHWEST WINDS. LOW CONFIDENCE FOR ANY STRATUS
DEVELOPMENT OVER THE TERMINAL FRIDAY NIGHT, BUT WILL MONITOR
CONDITIONS GIVEN THE FORECASTING CHALLENGES OVER THE LAST COUPLE OF
DAYS.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 1033 PM PDT THU APR 17 2025
MODERATE TO FRESH NORTHERLY BREEZE ACROSS THE OUTER COASTAL
WATERS WITH LIGHT AND VARIABLE WINDS CLOSER TO THE COAST. AS THE
WINDS DIMINISH, ROUGH SEAS ARE SUBSIDING NOW THROUGH FRIDAY
BEFORE ANOTHER STRONG BREEZE REBUILDS SEAS THIS WEEKEND INTO
EARLY NEXT WEEK.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 3 AM PDT SUNDAY
FOR PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...DIALH
MARINE...DIALH
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