776
FXUS66 KMTR 141903
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
1203 PM PDT FRI MAR 14 2025
..NEW AVIATION, MARINE
SYNOPSIS
ISSUED AT 1250 AM PDT FRI MAR 14 2025
RAIN AND GUSTY WINDS THIS MORNING WILL TAPER OFF BY THE
AFTERNOON. THE NEXT ROUND OF RAIN ARRIVES SUNDAY, WITH ONLY MINOR
IMPACTS EXPECTED.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 1250 AM PDT FRI MAR 14 2025
A PREFRONTAL RAIN BAND WILL PUSH THROUGH FROM ROUGHLY 3 AM TO 10
AM. THE TRIPLE POINT BETWEEN A WARM, COLD, AND OCCLUDED FRONT WILL
MOVE THROUGH THE BAY AREA AROUND MID-DAY, WHICH COULD TRIGGER A
FEW STRONG SHOWERS. THERE IS A 10-20% CHANCE FOR THUNDERSTORMS,
BUT THE THREAT ONLY LASTS FOR A BRIEF WINDOW AROUND NOON AS THE
MOISTURE BAND IS NARROW AND FAST MOVING WITH THIS SYSTEM. THE
WINDS ARE COMING IN STRONGER THAN PREVIOUSLY EXPECTED. THE PT.
ARENA BUOYS IS ALREADY GUSTING ABOVE 30 KTS, WHICH IS 10 KTS STRONGER
THAN ANY GUIDANCE SUGGESTED AT THIS TIME. I USED A 50/50 BLEND OF
THE 00Z LOCAL WRF AND 06Z HRRR FOR WIND AND GUSTS, WHICH PUT THE
COASTAL PENINSULA, SANTA CRUZ MOUNTAINS, AND INTERIOR EAST BAY
INTO WIND ADVISORY CRITERIA. IF THIS BLEND IS CORRECT, SOUTHERLY
WINDS IN THESE AREAS WILL GUST TO AROUND 45 MPH IN THE MID TO
LATE MORNING BEFORE SHIFTING TO WESTERLY AND DIMINISHING BACK TO
20-30 MPH GUSTS BEHIND THE FRONT. THE AFTERNOON WILL BE CHILLY
AND BREEZY, BUT THE RAIN WILL STOP AND SKIES BEGIN TO CLEAR
BEFORE THE SUN GOES DOWN TONIGHT.
LONG TERM
(SATURDAY THROUGH THURSDAY)
ISSUED AT 1250 AM PDT FRI MAR 14 2025
SATURDAY LOOKS LIKE THE BEST DAY FOR ANY OUTDOOR ACTIVITIES AS A
RIDGE BUILDS IN. NO RAIN, MUCH LIGHTER WIND, AND MORE SUNSHINE ARE
IN STORE. THE AIR MASS WILL STILL BE COLD, BUT IT WILL FEEL MUCH
WARMER WITH THE MORE PLEASANT CONDITIONS. THIS BREAK WON'T LAST
VERY LONG, HOWEVER, AS ANOTHER SYSTEM MOVES IN ON SUNDAY.
FORTUNATELY THE TIMING ON THIS KEEPS SHIFTING LATER, SO MOST
PEOPLE WILL BE ABLE TO ENJOY A DRY MORNING BEFORE THE RAIN CHANCES
START RAMPING UP IN THE AFTERNOON/EVENING. IF THE TIMING TREND
HOLDS, MOST OF THE RAIN WILL ACTUALLY FALL OVERNIGHT. THE CENTER
FOR WESTERN WEATHER AND WATER EXTREMES (CW3E) WRF ENSEMBLE MEAN IS
SHOWING IVT PEAKING AT ROUGHLY 325 KG/MS AND STAYING ABOVE 250
FOR AROUND 18 HOURS. THAT'S NOT QUITE INTENSE OR LONG ENOUGH TO
QUALIFY AS EVEN A WEAK ATMOSPHERIC RIVER, WHICH MEANS THIS EVENT
SHOULD BE MOSTLY BENEFICIAL, WITH NO SIGNIFICANT FLOODING THREAT.
OVERALL WE ARE EXPECTING AROUND 0.25"- 1", WITH A LITTLE MORE
POSSIBLE IN THE NORTH BAY MOUNTAINS. THE RAIN WILL START AS STEADY
STRATIFORM PRECIPITATION BEFORE THE COLD FRONT MOVES THROUGH
EARLY MONDAY AND THE MODE SWITCHES TO CONVECTION THROUGH MONDAY
AFTERNOON. WITH THE 1000-500 MB THICKNESS DROPPING BELOW 534 DM,
THESE CLOUDS WILL BE MOSTLY ABOVE THE FREEZING LEVEL, INCREASING
THE CHANCE FOR HIGH ELEVATION SNOW, HAIL, AND THUNDERSTORMS.
OF COURSE THE LIMITING FACTOR IS DRIER AIR MOVING IN
SIMULTANEOUSLY, WHICH WILL WORK TO INHIBIT ALL OF THE PHENOMENA
LISTED IN THE PREVIOUS SENTENCE. THIS DRIER AIR WILL CAUSE THE
CLOUDS TO CLEAR OUT. THE CLEAR SKIES, COMBINED WITH THE COLD AIR
MASS WILL LEAD TO A CHILLY START TUESDAY. HIGH PRESSURE WILL
CONTINUE TO BUILD IN THROUGH THE MIDDLE OF THE WEEK. IN THE
EXTENDED RANGE, THERE IS A CHANCE FOR VERY LIGHT RAIN ON THURSDAY,
BUT OVERALL THE PATTERN WILL FLATTEN OUT A BIT, WITH A TREND
TOWARDS WARMER AND DRIER CONDITIONS AS THE MONTH CONTINUES.
AVIATION
(18Z TAFS)
ISSUED AT 1202 PM PDT FRI MAR 14 2025
SHOWERS CHANCES LAST INTO THE EARLY EVENING BEFORE EXITING. BREEZY
TO GUSTY WEST WINDS REDUCE INTO THE MID TO LATE EVENING BEFORE WINDS
BECOME LIGHT TO MODERATE. MVFR CIGS LIFT INTO THE EVENING BUT MID-
LEVEL CLOUDS LAST THROUGH MUCH OF SATURDAY MORNING. WINDS BECOME
LIGHTER IN THE EARLY MORNING BUT LOOK TO INCREASE AGAIN FOR SATURDAY
AFTERNOON AS SKIES CLEAR.
VICINITY OF SFO...EXPECT STRONG AND GUSTY WEST WINDS INTO THE
EVENING BEFORE REDUCING, BUT STILL REMAINING BREEZY. SHOWERS AND
LOWER CLOUD COVER EXITS INTO THE EVENING, BUT SCATTERED MID-LEVEL
CLOUDS LINGER INTO LATE SATURDAY MORNING. EXPECT WINDS TO TURN LIGHT
AND VARIABLE FOR EARLY SATURDAY, BUT WILL BECOME MODERATE WESTERLY
WINDS AGAIN THAT AFTERNOON.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...GUSTY WINDS LAST THROUGH THE AFTERNOON WITH
PASSING SHOWERS. CIGS RISE THROUGH THE AFTERNOON, WITH PERSISTENT
MID-LEVEL CLOUDS. EXPECT WINDS TO REDUCE INT THE LATE EVENING AS
THE LAST FEW SHOWERS EXIT. WINDS BECOME LIGHT AND VARIABLE IN THE
LATE NIGHT.
MARINE
(TONIGHT THROUGH NEXT WEDNESDAY)
ISSUED AT 1202 PM PDT FRI MAR 14 2025
EXPECT GALE FORCE GUSTS AND ROUGH SEAS WILL ACROSS THE WATERS
THROUGH THE DAY. ROUGH, HAZARDOUS, CONDITIONS PERSIST THROUGH MUCH
OF NEXT WEEK AS A SERIES OF LOW PRESSURE SYSTEMS APPROACH THE
AREA, BRINGING WITH IT MULTIPLE ROUNDS OF ELEVATED SURF AND FRESH
TO STRONG WINDS.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY UNTIL 9 PM PDT THIS EVENING FOR MRY BAY-SF
BAY N OF BAY BRIDGE.
GALE WARNING UNTIL 3 PM PDT THIS AFTERNOON FOR PIGEON PT TO PT
PINOS 0-10 NM-PT ARENA TO PT REYES 0-10 NM-PT ARENA TO PT
REYES 10-60 NM-PT REYES TO PIGEON PT 0-10 NM.
GALE WARNING UNTIL 9 PM PDT THIS EVENING FOR PIGEON PT TO PT
PINOS 10-60 NM-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...FLYNN
LONG TERM....FLYNN
AVIATION...MURDOCK
MARINE...MURDOCK
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