522
FXUS66 KMTR 181208
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
508 AM PDT FRI APR 18 2025
..NEW AVIATION, MARINE
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
(12Z TAFS)
ISSUED AT 507 AM PDT FRI APR 18 2025
WIDESPREAD MVFR CIGS ARE AFFECTING THE REGION WITH LIFR/IFR CIGS
AFFECTING THE NORTH BAY TERMINALS AS WELL AS FOG AT STS. CLOUD COVER
BEGINS TO ERODE IN THE LATE MORNING AND COMPLETELY IN THE AFTERNOON.
WINDS STAY LIGHT TO MODERATE THROUGH THE MORNING, BUT INCREASE INTO
THE AFTERNOON BEFORE REDUCING AGAIN OVER THE EVENING. WAVES OF LOWER
CLOUDS MOVE ALONG THE COAST IN THE LATE AFTERNOON AND INTO THE
EVENING. THIS WILL GIVE INCONSISTENT CIGS FOR THE MONTEREY BAY
TERMINALS, BUT CIGS WILL FILL INTO FRIDAY EVENING FOR THAT AREA AS
WELL AS HAF. CLOUD COVER WILL STRUGGLE TO MOVE FURTHER INLAND, BUT
IFR CIGS DO LOOK TO MAKE IT TO APC LATE FRIDAY NIGHT.
VICINITY OF SFO...LIGHT WINDS AND MVFR CIGS LINGER INTO THE LATE
MORNING. SKIES CLEAR BEFORE NOON WITH BREEZY TO GUSTY WEST-NORTHWEST
WINDS BUILDING. THESE WINDS WILL LAST THROUGH THE EVENING AND INTO
THE EARLY NIGHT BEFORE BECOMING LIGHT.
SFO BRIDGE APPROACH...EXPECT CIGS TO CLEAR SLIGHTLY SOONER THAN SFO.
MONTEREY BAY TERMINALS...MVFR CIGS AND LIGHT WINDS LAST INTO THE
LATE MORNING BEFORE CIGS ERODE AND MODERATE WEST TO NORTH WEST WINDS
BUILD AROUND THE MONTEREY BAY. WAVES OF LOW CLOUDS WILL PASS THROUGH
THE BAY IN THE LATE AFTERNOON, OFFERING MOMENTS OF IFR TO MVFR CIGS.
WINDS REDUCE INTO THE LATE EVENING AND EARLY NIGHT AS CIGS FINALLY
FILL OVER THE TERMINALS.
|
MARINE
(TODAY THROUGH WEDNESDAY)
ISSUED AT 507 AM PDT FRI APR 18 2025
LIGHT TO MODERATE WINDS CONTINUE FOR FRIDAY WITH SEAS CONTINUING
TO SUBSIDE. BREEZY WINDS BUILD IN THE NORTHERN OUTER WATERS FOR
FRIDAY NIGHT WITH LIGHTER WINDS EXPECTED FOR THE INNER WATERS.
SEAS AND WINDS BECOME MORE ELEVATED INTO THE WEEKEND INTO THE NEXT
WORK 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...MURDOCK
MARINE...MURDOCK
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