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  
 
VISIT US AT WWW.WEATHER.GOV/SANFRANCISCO  
 
FOLLOW US ON FACEBOOK, TWITTER, AND YOUTUBE AT:  
WWW.FACEBOOK.COM/NWSBAYAREA  
WWW.TWITTER.COM/NWSBAYAREA  
WWW.YOUTUBE.COM/NWSBAYAREA  
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab CA Page Main Text Page