631
FXUS66 KMTR 120445
AFDMTR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA
945 PM PDT SUN APR 11 2021
SYNOPSIS
ANOTHER WARM AND SUNNY DAY IS ON TAP FOR MONDAY, AFTER
MORNING LOW CLOUDS BURN OFF. AN UPPER LOW APPROACHES THE GREAT
BASIN ON TUESDAY BRINGING SOME GUSTY WINDS TO OUR AREA,
ALONG WITH COOLER TEMPERATURES. DRY AND SEASONABLE CONDITIONS
PERSIST THROUGH THE FORECAST PERIOD, WITH INCREASING TEMPERATURES
LIKELY NEXT WEEKEND.
DISCUSSION...AS OF 09:45 PM PDT SUNDAY
IT WAS A WARM AND
PLEASANT FINISH TO THE WEEKEND, WITH TEMPERATURES IN MOST AREAS UP
TO SIX DEGREES WARMER THAN YESTERDAY. HOWEVER, LOCATIONS ALONG
THE COAST WERE MORE SIMILAR TO YESTERDAY TEMPERATURE-WISE, OWING
TO AFTERNOON SEA BREEZES.
CURRENT SATELLITE NIGHT PRODUCT IS SHOWING HIGH CLOUDS PASSING
OVER, WITH SOME PATCHY STRATUS BEGINNING TO DEVELOP AROUND
MONTEREY BAY AND ALONG THE SAN MATEO COUNTY COAST. COASTAL
PROFILERS REVEAL A MARINE LAYER DEPTH AROUND 1500 FT. THIS
CORRESPONDS WITH ASOS SITES AT KHAF, KMRY, AND KSNS REPORTING
CEILINGS BETWEEN 1100 AND 1500 FT. WRF AND HREF INDICATE AN
INTRUSION OF THE MARINE LAYER INTO COASTAL AREAS AROUND THE BAYS,
AS WE HAVE WITNESSED THE PAST COUPLE OF NIGHTS.
TOMORROW, WE CAN EXPECT SIMILAR CONDITIONS TO TODAY, WITH LOW
CLOUDS BURNING OFF MID TO LATE MORNING LEADING TO A MOSTLY SUNNY
AND WARM AFTERNOON. THIS WOULD MEAN 60S IN COASTAL AREAS, AND 70S
INLAND, WITH SOME LOW 80S IN THE WARMEST SPOTS.
LATE MONDAY NIGHT INTO TUESDAY MORNING AN UPPER LOW WILL FORM OVER
EASTERN OREGON AND WILL MOVE OVER THE GREAT BASIN THROUGH THE DAY.
THIS WILL SWEEP A COLD FRONT THROUGH OUR AREA, BRINGING SOME GUSTY
WINDS. NAM AND WRF KEEP THE STRONGEST 925 MB WINDS (40+ KTS)
OFFSHORE. AS A RESULT, THIS DOES NOT APPEAR TO BE A HIGH IMPACT
WIND EVENT FOR OUR AREA. HOWEVER, COASTAL AREAS AND TERRAIN GAPS
MAY SEE WINDS APPROACHING OR EXCEEDING ADVISORY CRITERIA. THESE
WINDIER SPOTS, SUCH AS THE SAN BRUNO GAP AND ALTAMONT PASS, ARE
PICKED UP BY THE WRF. SUSTAINED WINDS OF 20-25 MPH, WITH GUSTS
35-45 MPH ARE POSSIBLE. ECMWF ENSEMBLE MEMBERS HAVE GUSTS 30-40
MPH AT KSFO TUESDAY AFTERNOON, WHICH APPEARS TO BE THE TIMEFRAME
FOR PEAK GUSTS. MODELS SHOW WINDS SETTLING DOWN BY TUESDAY
EVENING. AT THIS TIME, HIGH WINDS DO NO APPEAR TO BE WIDESPREAD
ENOUGH TO REQUIRE A WIND ADVISORY, BUT THIS WILL OF COURSE BE
MONITORED.
LIGHTER WINDS AND SEASONABLE TEMPERATURES ARE FORECAST WEDNESDAY
THROUGH FRIDAY, AS THE UPPER LOW MOVES FURTHER EAST. BY SATURDAY,
HIGH PRESSURE NOSES INTO THE AREA, ALLOWING TEMPERATURES TO
INCREASE BY A FEW DEGREES, WITH MORE SIGNIFICANT WARMING ON
SUNDAY. THERE DO NOT APPEAR TO BE SIGNIFICANT HEAT IMPACTS AT THIS
TIME, BUT THINGS CAN EASILY CHANGE SEVEN DAYS OUT. UNFORTUNATELY,
DRY CONDITIONS WILL PERSIST, WITH NOT EVEN A SLIGHT CHANCE OF RAIN
UNTIL THE END OF THE MONTH, AS PER ENSEMBLES.
AVIATION...AS OF 04:42 PM PDT SUNDAY
FOR THE 00Z TAFS. VFR WITH
SOME HIGH CLOUDS PASSING OVER FROM THE OCEAN. WINDS REMAIN BREEZY,
WITH COASTAL GAPS SHOWING STRONGER ONSHORE WINDS BETWEEN 13 TO 18
KTS. A MUCH WEAKER PRESSURE GRADIENT LEADS TO THE FORECAST
BRINGING A RETURN OF STRATUS AT MVFR LEVELS FOR THE OVERNIGHT
HOURS AS WINDS SUBSIDE. THERE IS CHANCE FOR FOG TO DEVELOP AT
NORTH BAY TERMINALS. CLOUD COVER WILL LINGER A BIT LONGER WITH NOT
MIXING OUT UNTIL AFTER 17Z. VFR EXPECTED MONDAY WITH HIGHER
CLOUDS LINGERING AROUND THE REGION AS ANOTHER ONSHORE SEABREEZE
DEVELOPS.
VICINITY OF KSFO...HIGH CLOUDS CONTINUE TO PASS OVER THE TERMINAL
UNDER SUNNY SKIES. NORTHWEST WINDS SPILL THROUGH THE SAN BRUNO GAP
AND ARE STILL BLOWING UP TO 20 KTS. EXPECTED WINDS TO SLOWLY
SUBSIDE INTO THE EVENING.STRATUS CLOUDS ARE EXPECTED TO SPILL INTO
THE BAY AND MOVE OVER TO THE EAST BAY. MID LEVEL CLOUDS ARE
EXPECTED NEAR THE TERMINAL WITH A CHANCE FOR MVFR CONDITIONS IN
THE EARLY MONDAY MORNING HOURS. VFR EXPECTED MONDAY AFTERNOON AS
MODERATE ONSHORE WINDS RETURN.
SFO BRIDGE APPROACH...SIMILAR TO KSFO.
MONTEREY BAY TERMINALS...CURRENTLY VFR AND BREEZY, BUT MIDLEVEL
STRATUS CLOUDS ARE EXPECTED TO RETURN SUNDAY EVENING AS WINDS
SUBSIDE. CIGS ARE EXPECTED TO HOVER AROUND THE 1000 FT THRESHOLD,
WITH A CHANCE FOR IFR CIGS EARLY MONDAY MORNING. STRATUS CLOUDS
CAN BE EXPECTED TO LINGER AROUND THE VICINITY OF COASTAL TERMINALS
ON MONDAY, BUT VFR WITH AN AFTERNOON SEABREEZE IS EXPECTED.
MARINE...AS OF 08:13 PM PDT SUNDAY
STRONG NORTHERLY WINDS
PREVAIL ON SUNDAY WITH GALE FORCE GUSTS OVER THE NORTHERN OUTER
WATERS TODAY. THESE WINDS CAN GENERATE STEEP WIND WAVES AT 8 TO
10 SECONDS. A MODERATE NORTHWEST SWELL ARRIVES TODAY AND WILL
MERGE WITH THE STEEP WIND WAVES, ESPECIALLY IN THE NORTHERN AND
OUTER WATERS MAKING FOR STEEP SEAS SLOWLY RECEDING TO JUST THE
OUTER WATERS THROUGH TODAY AND INTO MONDAY.
MTR WATCHES/WARNINGS/ADVISORIES
.TNGT...SCA...MRY BAY UNTIL 9 PM
SCA...PT REYES TO PIGEON PT 0-10 NM UNTIL 9 PM
SCA...PIGEON PT TO PT PINOS 0-10 NM UNTIL 9 PM
GLW...PT ARENA TO PIGEON PT 10-60 NM UNTIL 9 PM
SCA...PT ARENA TO PT REYES 0-10 NM UNTIL 3 AM
SCA...PT PINOS TO PT PIEDRAS BLANCAS 0-10 NM UNTIL 3 AM
SCA...PIGEON PT TO PT PIEDRAS BLANCAS 10-60 NM UNTIL 3 AM
PUBLIC FORECAST: LORBER
AVIATION: DK
MARINE: DK
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