275
FXUS66 KMTR 312333
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO CA
433 PM PDT TUE MAR 31 2026
..NEW AVIATION, MARINE
KEY MESSAGES
UPDATED AT 1152 AM PDT TUE MAR 31 2026
- SEASONABLY COOL CONDITIONS WITH RAIN CHANCES THROUGH THURSDAY
- ABOVE NORMAL TEMPERATURES AND OFFSHORE FLOW RETURN FRIDAY AND
CONTINUE OVER THE WEEKEND
SHORT TERM
ISSUED AT 1152 AM PDT TUE MAR 31 2026
(THIS AFTERNOON THROUGH THURSDAY MORNING)
IT ONLY TOOK 29 DAYS, BUT IT'S FINALLY RAINING. A STATIONARY FRONT
IS OFFERING AN AREA OF CONVERGENCE FOR ITS TROPICAL MOISTURE TAP.
RAIN SHOWER ACTIVITY WILL CONTINUE TO DRIFT SOUTH THROUGH THE DAY AS
SURFACE HIGH PRESSURE TRIES TO NOSE IN FROM THE EASTERN PACIFIC
OCEAN. A GALE FORCE LOW IN THE GULF OF ALASKA WILL PUT A STOP TO
THAT AS IT HEADS TO THE WASHINGTON/CANADA BORDER. THE ATTENDANT COLD
FRONT WILL BRING US A WINTER-LIKE FEEL WITH BELOW NORMAL
TEMPERATURES, GUSTY CONDITIONS, AND RAIN. SOUTHWESTERLY WINDS WILL
INCREASE AHEAD OF THE COLD FRONT WITH NORTHWESTERLY WINDS DEVELOPING
IN THE POST-FRONTAL ENVIRONMENT. WIDESPREAD GUSTS OF 20-30 MPH CAN
BE EXPECTED WITH GUSTS UP TO 40 MPH IN THE HIGHEST TERRAIN. RAINFALL
TOTALS ARE EXPECTED TO BE IN THE 0.10"-0.25" RANGE WITH LOCALLY
HIGHER TOTALS IN THE HIGHER TERRAIN OF THE NORTH BAY AND LOCALLY
LOWER TOTALS IN THE INTERIOR CENTRAL COAST. SLICK ROADWAYS CAN BE
EXPECTED DUE TO THE DRY SPELL THAT HAS ALLOWED OIL TO ACCUMULATE.
LONG TERM
ISSUED AT 1152 AM PDT TUE MAR 31 2026
(THURSDAY NIGHT THROUGH NEXT MONDAY)
THE PATTERN WILL QUICKLY CHANGE THURSDAY AFTERNOON AS UPPER-LEVEL
SHORTWAVE RIDGING NOSES IN FROM THE EASTERN PACIFIC OCEAN. THE SHORT
WAVELENGTH OF THE AFOREMENTIONED TROUGH AND RIDGE WILL TIGHTEN THE
PRESSURE GRADIENT. STRONG NORTHERLY WINDS WILL RESULT, PRIMARILY
AFFECTING EXPOSED AREAS LIKE THE HIGHER TERRAIN AND MARINE
ENVIRONMENT. THE SFO-WMC PRESSURE GRADIENT IS EXPECTED TO BECOME
NEGATIVE THURSDAY NIGHT AS THE WAVELENGTH MOVES INLAND, RESULTING IN
OFFSHORE FLOW. AT 5 AM FRIDAY, THE ECMWF ENSEMBLE MEAN IS
FORECASTING THE GRADIENT TO BE -9.81 MB WHILE THE GEFS MEAN IS
FORECASTING THE GRADIENT TO BE -7.76 MB. THE 2 MB DISCREPANCY IS DUE
TO THE ECMWF ENSEMBLE SHOWING A STRONGER HIGH AND STRONGER LOW
CLOSER TOGETHER THAN WEAKER FEATURES FARTHER APART IN THE GEFS. THIS
UNCERTAINTY IS PROPAGATED THROUGH FRIDAY AND SATURDAY WITH THE ECMWF
ENSEMBLE BOTTOMING OUT AT -10.96 MB AT 5 AM SATURDAY WHILE THE GEFS
IS WELL ON ITS RELAXING TREND AT -5.24 MB. NONETHELESS, A MODERATE
OFFSHORE FLOW EVENT CAN BE EXPECTED THURSDAY NIGHT THROUGH THE
WEEKEND WITH A 35 KNOT 925 MILLIBAR JET STREAK ACROSS THE NORTH BAY.
THIS WILL TRANSLATE TO GUSTS OF 40 TO 50 MPH IN THE HIGHER TERRAIN,
NAMELY THE NORTH BAY INTERIOR MOUNTAINS, EAST BAY HILLS, AND EASTERN
SANTA CLARA HILLS. THE RIDGE WILL ALSO SEND TEMPERATURES SOARING
BACK TO WELL ABOVE NORMAL.
AVIATION
(00Z TAFS)
ISSUED AT 409 PM PDT TUE MAR 31 2026
EXPECT A MIX OF VFR/MVFR CIGS THROUGH TONIGHT AND MUCH OF
WEDNESDAY MORNING. THE BULK OF RAINFALL TONIGHT WILL WIND DOWN
AFTER SUNSET WITH SOME SCATTERED LIGHT RAIN PERSISTING OVER THE
BAY AREA UNTIL MIDNIGHT. CIGS WILL MOSTLY REMAIN BETWEEN MFVR/VFR
THROUGH THE OVERNIGHT HOURS. THE NORTH BAY TERMINALS, ESPECIALLY
KSTS IS EXPECTED TO DROP TO IFR CIGS AS RAIN MOVES THROUGH EARLY
WEDNESDAY MORNING.
VICINITY OF SFO...EXPECT VFR TO PREVAIL THROUGH MUCH OF THE
OVERNIGHT, THEN DROPPING TO MVFR AROUND SUNRISE WEDNESDAY AMID THE
NEXT ROUND OF SCATTERED LIGHT RAIN ACROSS THE BAY AREA. EXPECT
LIGHT SOUTHERLY WINDS THROUGH MOST OF WEDNESDAY MORNING THEN
BECOMING BREEZY OUT OF THE SOUTHWEST WEDNESDAY AFTERNOON AND
EVENTUALLY NORTHWEST BEHIND THE FRONT WEDNESDAY NIGHT.
SFO BRIDGE APPROACH...SIMILAR AS SFO.
MONTEREY BAY TERMINALS...VFR THE REMAINDER OF THIS EVENING WITH
MVFR CIGS EXPECTED TO DEVELOP LATE TONIGHT THROUGH MUCH OF
WEDNESDAY MORNING WITH SOME SCATTERED LIGHT RAIN ACTIVITY POSSIBLE
OVERNIGHT. LIGHT SOUTHERLY WINDS WEDNESDAY MORNING BECOME BREEZY
OUT OF THE SOUTHWEST BEHIND A COLD FRONT WEDNESDAY AFTERNOON WITH
VFR CIGS PERSISTING THROUGH THE REMAINDER OF THE FORECAST PERIOD.
MARINE
(TONIGHT THROUGH NEXT SUNDAY)
ISSUED AT 409 PM PDT TUE MAR 31 2026
RAIN SHOWERS WILL CONTINUE TODAY AROUND A SURFACE LOW JUST
BEGINNING TO ENTER OUR WATERS AND ALONG THE ASSOCIATED STATIONARY
FRONT. GENTLE SOUTHWESTERLY BREEZES TODAY WILL INCREASE TO BECOME
MODERATE TO FRESH TOMORROW AHEAD OF A COLD FRONT. FRESH TO STRONG
NORTHWESTERLY BREEZES WILL DEVELOP IN THE POST-FRONTAL ENVIRONMENT
WEDNESDAY NIGHT INTO THURSDAY MORNING. STRONG NORTHERLY BREEZES
WILL DEVELOP THURSDAY AFTERNOON AND PERSIST INTO FRIDAY. MODERATE
SEAS WILL BUILD TO BECOME ROUGH THURSDAY INTO FRIDAY. WIDESPREAD
HAZARDOUS CONDITIONS ARE EXPECTED THURSDAY AND FRIDAY. CONDITIONS
IMPROVE BY THE WEEKEND.
MTR WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...SMALL CRAFT ADVISORY FROM 3 PM WEDNESDAY TO 3 AM PDT THURSDAY
FOR 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.
SHORT TERM...SARMENT
LONG TERM....SARMENT
AVIATION...JM
MARINE...SARMENT
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