520
FXUS66 KMTR 170901
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
201 AM PDT MON MAR 17 2025
..NEW SYNOPSIS, SHORT TERM, LONG TERM
SYNOPSIS
ISSUED AT 200 AM PDT MON MAR 17 2025
RAIN WILL CONTINUE ACROSS THE BAY AREA AND CENTRAL COAST THROUGH THE
MORNING WITH POST-FRONTAL SHOWERS AND THUNDERSTORMS POSSIBLE THROUGH
THE DAY. LIGHT RAIN IS EXPECTED IN THE BAY AREA ON WEDNESDAY.
TEMPERATURES REMAIN COOL TO AVERAGE THROUGH THE WEEK WITH A GRADUAL
WARMING TREND TOWARDS THE LATTER PART OF THE WEEK.
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 200 AM PDT MON MAR 17 2025
RADAR IMAGERY IS SHOWING TWO SUBSTANTIAL RAIN BANDS MOVING THROUGH
THE FORECAST REGION, ONE THAT IS MOVING THROUGH THE SOUTH BAY AND
THE MONTEREY BAY REGION, AND THE OTHER COMING THROUGH THE NORTH
BAY INTO THE SAN MATEO PENINSULA. BETWEEN THE TWO BANDS,
SCATTERED SHOWERS PREVAIL, AND THERE'S EVEN BEEN SIGNS OF AN NCFR,
FEEBLE THAT THEY MAY BE, BUT ONE WHICH HAS BEEN ASSOCIATED WITH
THE CHANGE IN WIND DIRECTION FROM SOUTHERLY FLOW TO A WESTERLY
REGIME. THESE RAIN BANDS WILL CONTINUE MOVING THROUGH THE REGION
INTO THE EARLY MORNING HOURS. SCATTERED SHOWERS WILL THEN LINGER
THROUGH THE EVENING.
IN THE POST-FRONTAL ENVIRONMENT, THE COLDER AIR ALOFT WILL HELP
INCREASE LAPSE RATES, ALLOWING FOR A CHANCE OF CONVECTIVE ACTIVITY
IN THE BAY AREA AND CENTRAL COAST. THE STORM PREDICTION CENTER HAS
PLACED THE BAY AREA AND MUCH OF THE CENTRAL COAST, INCLUDING THE
MONTEREY BAY REGION, INTO A GENERAL RISK FOR NON-SEVERE
THUNDERSTORMS. ALTHOUGH THE HIGHEST CONVECTIVE RISK REMAINS CENTERED
ACROSS THE CENTRAL VALLEY, THE PROBABILITY OF THUNDERSTORMS REMAINS
AT 10-20% FOR TODAY, AND THE POTENTIAL FOR SMALL HAIL, LOCALLY HEAVY
DOWNPOURS, AND LOCALIZED STRONG GUSTS CONTINUES THROUGH THE DAY. THE
CONVECTIVE RISK SHOULD DIMINISH THIS EVENING, AS THE LACK OF SOLAR
HEATING WILL HELP STABILIZE THE ATMOSPHERE.
BREEZY AND GUSTY WINDS WILL DEVELOP ACROSS THE REGION THIS
AFTERNOON, ALTHOUGH THE WIND SPEEDS WILL NOT BE AS STRONG AS THEY
WERE YESTERDAY. GUSTS OF AROUND 25 TO 35 MILES PER HOUR ARE EXPECTED
ACROSS THE REGION. WE ARE NOT EXPECTING WIDESPREAD WIND ADVISORY-
LEVEL GUSTS TO DEVELOP IN THE REGION, BUT THERE IS A POTENTIAL FOR
GUSTS UP TO 45 MILES PER HOUR ALONG THE COASTS AND AT THE RIDGELINES.
LOW TEMPERATURES THIS MORNING RANGE FROM THE MIDDLE 40S TO NEAR 50
ACROSS THE LOWER ELEVATIONS, INTO THE UPPER 30S TO LOWER 40S IN THE
HIGHER ELEVATIONS. TODAY'S HIGHS RANGE FROM THE MIDDLE TO UPPER 50S
IN THE LOWER ELEVATIONS, DOWN TO THE MIDDLE 40S TO LOWER 50S IN THE
HIGHER ELEVATIONS.
LONG TERM
(TUESDAY THROUGH SUNDAY)
ISSUED AT 200 AM PDT MON MAR 17 2025
A NEW RAINMAKER ARRIVES ON WEDNESDAY WITH GENERALLY BENEFICIAL
IMPACTS ACROSS THE BAY AREA, WITH UP TO 0.5" IN THE SONOMA COASTAL
RANGES AND THE MAYACAMAS, 0.1-0.25" IN THE NORTH BAY VALLEYS, RAIN
TOTALS RANGE FROM A FEW HUNDREDTHS OF AN INCH TO AROUND A TENTH OF
AN INCH IN THE BAY AREA, UP TO 0.25" IN THE SANTA CRUZ MOUNTAINS,
AND LESS THAN 0.1" IN MONTEREY AND SAN BENITO COUNTIES. A SYSTEM
THAT WAS EXPECTED TO BRUSH PAST THE NORTH BAY LATER IN THE WEEK HAS
CONTINUED TO DRIFT TOWARDS THE NORTH, AND THE CURRENT FORECAST SHOWS
NO APPRECIABLE RAINFALL ACROSS THE FORECAST REGION AFTER THURSDAY.
THROUGHOUT THE REST OF THE WEEK, TEMPERATURES REMAIN COOL TO NEAR
THE SEASONAL AVERAGE ACROSS THE REGION. A GRADUAL WARMING TREND
BEGINS ON TUESDAY, WITH TEMPERATURES IN THE INLAND VALLEYS REACHING
NEAR THE SEASONAL AVERAGE, OR THE MIDDLE TO UPPER 60S, BY MIDWEEK.
BY THE WEEKEND, AS A SHORTWAVE RIDGE BUILDS OVER THE WESTERN UNITED
STATES, MOST OF THE FORECAST REGION WILL SEE TEMPERATURES NEAR OR
SLIGHTLY ABOVE THE SEASONAL AVERAGE, WITH TEMPERATURES REACHING THE
LOWER TO MIDDLE 70S IN THE INLAND VALLEYS AND THE LOWER TO MIDDLE
60S ALONG THE COAST.
AVIATION
(06Z TAFS)
ISSUED AT 1025 PM PDT SUN MAR 16 2025
GUSTY ONSHORE WINDS HAVE EASED SOMEWHAT BUT WILL REMAIN ELEVATED THROUGH
EARLY MONDAY MORNING, THEN INCREASE MONDAY AFTERNOON. CEILINGS
WILL HOVER BETWEEN MVFR/VFR, BECOMING MVFR WHEN RAIN IS IMPACTING
THE TERMINALS. SCATTERED LIGHT RAIN CHANCES WILL PERSIST OVERNIGHT
THROUGH MONDAY EVENING.
VICINITY OF SFO...CEILINGS WILL HOVER BETWEEN VFR AND MVFR. WINDS
EASED SOMEWHAT AFTER SUNSET BUT REMAIN BREEZY WITH SCATTERED
LIGHT RAIN IN THE VICINITY OF KSFO/KOAK THROUGH THE OVERNIGHT AND
MUCH OF MONDAY. WINDS WILL INCREASE, BECOMING STRONG AGAIN LATER
MONDAY MORNING THROUGH THE EVENING HOURS.
SFO BRIDGE APPROACH...SIMILAR TO SFO.
MONTEREY BAY TERMINALS...CURRENTLY VFR, WITH OCCASIONAL DROPS INTO
MVFR POSSIBLE WHEN RAIN PASSES OVER THE TERMINALS. WINDS WILL
REAMIN BREEZY THROUGH MUCH OF THE FORECAST PERIOD, BECOMING GUSTY
ONCE AGAIN MONDAY AFTERNOON WITH MVFR CEILINGS EXPECTED LATE IN
THE FORECAST PERIOD MONDAY NIGHT.
MARINE
(TONIGHT THROUGH NEXT SATURDAY)
ISSUED AT 928 PM PDT SUN MAR 16 2025
HAZARDOUS CONDITIONS WITH ROUGH TO VERY ROUGH SEAS WILL CONTINUE
THROUGH EARLY MONDAY MORNING, ALONG WITH A SLIGHT CHANCE OF
THUNDERSTORMS THROUGH MONDAY AFTERNOON. WINDS EASE SLIGHTLY
BECOMING MODERATE BY TUESDAY, WITH SEAS ABATING FOR A SHORT TIME
BEFORE ANOTHER COLD FRONT PUSHES THROUGH OUR AREA ON WEDNESDAY
BRINGING ANOTHER ROUND OF ROUGH SEAS AND INCREASING CHANCES FOR
RAINFALL.
BEACHES
ISSUED AT 236 PM PDT SUN MAR 16 2025
A MODERATE PERIOD WESTERLY SWELL IS BRINGING A MINOR RISK FOR
SNEAKER WAVES ALONG WITH IT. IF RAIN AND STRONG AND GUSTY SOUTHERLY
WINDS PELTING YOU WITH SAND ISN'T REASON ENOUGH TO STAY AWAY FROM
THE BEACH, PLEASE REMEMBER TO STAY OFF OF ROCKS AND JETTIES, KEEP
PETS ON A LEASH, AND NEVER TURN YOUR BACK ON THE OCEAN!
SARMENT
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...GALE WARNING UNTIL 3 AM PDT EARLY THIS MORNING FOR PIGEON PT TO
PT PINOS 0-10 NM-PIGEON PT TO PT PINOS 10-60 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-SF BAY N OF BAY BRIDGE.
SMALL CRAFT ADVISORY UNTIL 3 AM PDT EARLY THIS MORNING FOR MRY
BAY-PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM.
SHORT TERM...DIALH
LONG TERM....DIALH
AVIATION...JM
MARINE...JM
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