477
FXUS66 KMTR 172034
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
134 PM PDT MON MAR 17 2025
..NEW SYNOPSIS, SHORT TERM, LONG TERM
SYNOPSIS
ISSUED AT 132 PM PDT MON MAR 17 2025
POST-FRONTAL SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH THE DAY
BEFORE TAPERING OFF BY TONIGHT. LIGHT RAIN IS EXPECTED IN THE BAY
AREA ON WEDNESDAY AND WEDNESDAY NIGHT, MOSTLY FOCUSED ON THE NORTH
BAY. A GRADUAL WARMING TREND IS THEN EXPECTED OVER THE WEEKEND WITH
TEMPERATURES ABOVE NORMAL BY NEXT MONDAY.
SHORT TERM
(THIS EVENING THROUGH TUESDAY)
ISSUED AT 132 PM PDT MON MAR 17 2025
ISOLATED TO SCATTERED RAIN SHOWERS ARE MOVING OVER THE REGION EARLY
THIS AFTERNOON. WE ALSO HAVE A 15-20% CHANCE OF THUNDERSTORMS THIS
AFTERNOON AS THE ATMOSPHERE BECOMES MORE UNSTABLE WITH COOLING
TEMPERATURES ALOFT AND MUCAPE VALUES ARE FORECAST TO RISE TO ABOVE
250 J/KG. GREATEST POTENTIAL BEING OVER THE EAST BAY AND NORTH BAY
REGIONS. ANY HEAVIER SHOWER OR THUNDERSTORMS WILL BE CAPABLE OF
PRODUCING SMALL HAIL, LOCALLY HEAVY DOWNPOURS, AND STRONG GUSTY
WINDS.
AS CONDITIONS BEGIN TO DRY OVERNIGHT AND WINDS EASE, TEMPERATURES
WILL DROP INTO THE LOW-TO-MID 30S IN THE NORTH BAY VALLEYS, THE
SOUTHERN SALINAS VALLEY, THE SANTA LUCIA RANGE, AND THE MOUNTAINS OF
SAN BENITO AND INTERIOR MONTEREY COUNTIES. THUS, A FROST ADVISORY
HAS BEEN ISSUED FROM 2 AM TO 9 AM TUESDAY FOR THE AFOREMENTIONED
AREAS. THESE COLD TEMPERATURES WILL LEAD TO THE RISK OF HYPOTHERMIA
FOR VULNERABLE POPULATIONS, INCLUDING CHILDREN, THE ELDERLY, AND
PEOPLE WITHOUT ADEQUATE HEATING.
TUESDAY IS FORECAST TO BE DRY WITH AFTERNOON TEMPERATURES REACHING
INTO THE MID 50S TO LOW 60S UNDER MOSTLY SUNNY SKIES.
LONG TERM
(TUESDAY NIGHT THROUGH NEXT SUNDAY)
ISSUED AT 132 PM PDT MON MAR 17 2025
ANOTHER COLD MORNING IS IN STORE FOR WEDNESDAY AS TEMPERATURES ONCE
AGAIN DROP INTO THE LOW-TO-MID 30S FOR INTERIOR PORTIONS OF THE
REGION WITH FROST ADVISORIES LIKELY NEEDED.
OUR NEXT CHANCE OF PRECIPITATION WILL BE ON WEDNESDAY AND WEDNESDAY
NIGHT AS ANOTHER FRONTAL SYSTEM IMPACTS THE REGION. RAINFALL AMOUNTS
AND CHANCES OF PRECIPITATION CONTINUE TO SEE A LOWERING TREND. IT IS
NOW LOOKING LIKE THE HIGHEST TOTALS WILL BE ACROSS THE NORTH BAY
WITH THE COASTAL RANGES AND HIGHER PEAKS ACROSS NAPA AND SONOMA
COUNTY PICKING UP AROUND 0.33" WITH 0.05-0.25" IN THE VALLEYS OF THE
NORTH BAY. SOUTH OF THE GOLDEN GATE, WE ARE EXPECTING TO SEE UP TO
0.05" WITH LITTLE TO NO RAINFALL ACROSS THE CENTRAL COAST.
A RIDGE OF HIGH PRESSURE WILL BEGIN TO BUILD OVER THE EASTERN
PACIFIC LATE WEEK. AS THE SYSTEM MOVES CLOSER TO THE COAST
TEMPERATURES WILL BE ON THE RISE TO NEAR SEASONAL AVERAGES. BY
MONDAY AND TUESDAY, TEMPERATURES LOOK TO BE UP TO 10 DEGREES ABOVE
AVERAGE AS THE RIDGE ALOFT BUILDS OVER THE REGION. OVERNIGHT
TEMPERATURES WILL ALSO BE ON THE RISE, LESSENING THE NEED FOR FROST
ADVISORIES.
AVIATION
(18Z TAFS)
ISSUED AT 1017 AM PDT MON MAR 17 2025
A MESSY AND TRANSIENT TAF CYCLE IS AHEAD OF US AS THE COLD FRONT
THAT BROUGHT WIDESPREAD RAINFALL OVERNIGHT HAS LEFT US WITH, YOU
GUESSED IT, COLDER AIR WHICH IS LEADING TO INSTABILITY ACROSS THE
AREA. BECAUSE OF THIS, THERE'S A SLIGHT CHANCE FOR THUNDERSTORMS
THROUGH SUNSET TONIGHT WHICH WOULD POSE THE RISK FOR LOCALLY HEAVY
RAINFALL AND GUSTY WINDS, LIGHTNING, AND PEA SIZED HAIL. WHILE NO
LIGHTNING HAS BEEN REPORTED YET AND EVEN IF THAT REMAINS TRUE THE
REST OF THE DAY, THE OTHER HAZARDS REMAIN IN PLAY AND HAVE ALREADY
BEEN OBSERVED ACROSS THE REGION. RAIN SHOWER ACTIVITY AND WINDS WILL
DIMINISH AFTER SUNSET.
VICINITY OF SFO...CURRENTLY VFR WITH SOUTHWESTERLY FLOW.
SOUTHWESTERLY WINDS WILL EVER SO SLIGHTLY VEER TO BECOME WESTERLY
AND GUSTY THIS AFTERNOON WITH GUSTS UP TO 35 KNOTS TO BE EXPECTED
THIS AFTERNOON AND EVENING. VFR CONDITIONS ARE EXPECTED TO PREVAIL;
HOWEVER, IF A RAIN SHOWER PASSES DIRECTLY OVER THE TERMINAL EXPECT A
REDUCTION IN CEILINGS AND VISIBILITIES.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CURRENTLY VFR WITH SOUTHERLY FLOW AT MRY
AND MVFR AND CALM AT SNS. VFR CONDITIONS ARE EXPECTED TO PREVAIL;
HOWEVER, IF A RAIN SHOWER PASSES DIRECTLY OVER THE TERMINAL EXPECT A
REDUCTION IN CEILINGS AND VISIBILITIES.
MARINE
(TODAY THROUGH SATURDAY)
ISSUED AT 1017 AM PDT MON MAR 17 2025
WIDESPREAD HAZARDOUS CONDITIONS CONTINUE TODAY WITH STRONG
NORTHWESTERLY WINDS WITH GALE FORCE GUSTS AND ROUGH TO VERY ROUGH
SEAS. THERE'S ALSO A SLIGHT CHANCE FOR THUNDERSTORMS TODAY WHICH
WOULD POSE THE RISK FOR LOCALLY HEAVY RAINFALL AND GUSTY WINDS,
LIGHTNING, AND PEA SIZED HAIL. ANOTHER SYSTEM WILL BRING RENEWED
CHANCES FOR RAINFALL, ROUGH SEAS, AND A STRONG SOUTHERLY BREEZE
WEDNESDAY INTO THURSDAY.
BEACHES
ISSUED AT 450 AM PDT MON MAR 16 2025
STILL NOT A PLEASANT DAY FOR A BEACH VISIT WITH LINGERING SHOWERS
AND ANOTHER PUSH OF STRONGER WINDS IN THE AFTERNOON. ADDITIONALLY,
FRESH SWELL WILL LEAD TO BIGGER SHORE BREAK LATER THIS AFTERNOON
AND EARLY TONIGHT. ROUGH SURF ZONE IS EXPECTED. IF YOU BRAVE THE
ELEMENTS AND HIT THE BEACH, DON'T TURN YOUR BACK TO THE OCEAN
TODAY.
MM
MTR WATCHES/WARNINGS/ADVISORIES
CA...FROST ADVISORY FROM 2 AM TO 9 AM PDT TUESDAY FOR CAZ506-516>518.
PZ...SMALL CRAFT ADVISORY UNTIL 9 AM PDT TUESDAY FOR MRY BAY-PIGEON
PT TO PT PINOS 0-10 NM-PT ARENA TO PT REYES 0-10 NM-PT
REYES TO PIGEON PT 0-10 NM-SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 9 PM PDT TUESDAY FOR PT PINOS TO PT
PIEDRAS BLANCAS 0-10 NM.
SMALL CRAFT ADVISORY UNTIL 3 PM PDT TUESDAY FOR PIGEON PT TO PT
PINOS 10-60 NM-PT ARENA TO PT REYES 10-60 NM.
SHORT TERM...RGASS
LONG TERM....RGASS
AVIATION...SARMENT
MARINE...SARMENT
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