071
FXUS66 KSGX 212032
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
132 PM PDT MON APR 21 2025
SYNOPSIS
NIGHT AND MORNING LOW CLOUDS ARE EXPECTED EACH DAY AT THE COAST
EARLY THIS WEEK, BECOMING MORE WIDESPREAD INTO THE VALLEYS FOR THE
MIDDLE TO END OF THE WEEK. INCREASED SEA BREEZE WINDS ARE EXPECTED
EACH AFTERNOON AND EVENING FOR THE MOUNTAINS AND DESERTS. A COOLING
TREND WILL START TODAY WEST OF THE MOUNTAINS. FOR THE MOUNTAINS AND
DESERTS A FEW DEGREES OF WARMING EXPECTED EARLY IN THE WEEK, BEFORE
A COOLING TREND OF THE MIDDLE TO END OF THE WEEK. GRADUAL WARMING IS
EXPECTED EARLY NEXT WEEK.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
AT 1 PM, A FEW AREAS OF LOW CLOUDS WERE LINGERING ALONG THE SAN
DIEGO COAST. ELSEWHERE, IT'S MOSTLY SUNNY WITH AREAS OF HIGH CLOUDS
MOVING EAST TOWARDS THE DESERTS. A SERIES OF PASSING TROUGHS THIS
WEEK WILL MAINTAIN ONSHORE FLOW ACROSS THE REGION. THIS WILL CAUSE
THE MARINE LAYER TO DEEPEN THROUGH THE WEEK REACHING THE WESTERN
VALLEYS BY TOMORROW AND FILLING IN MUCH OF THE COASTAL BASIN BY
WEDNESDAY. IN ADDITION, ELEVATED SEA BREEZE WINDS CAN BE EXPECTED
MOST AFTERNOONS AND EVENINGS FOR THE MOUNTAINS, DESERTS, AND PASSES.
A COOLING TREND FOR THE COAST AND VALLEYS WILL CONTINUE THROUGH
SATURDAY. THE MOUNTAINS AND DESERTS WILL WARM A FEW DEGREES
TOMORROW, BEFORE A COOLING TREND SETS IN THROUGH SATURDAY. FOR EARLY
NEXT WEEK, HIGH PRESSURE WILL BEGIN TO STRENGTHEN OFF THE WEST COAST
WITH WARMING FOR SOUTHERN CALIFORNIA.
THERE REMAINS UNCERTAINTY IN THE UPPER LEVEL PATTERN FOR FRIDAY
THROUGH THE WEEKEND. WHILE THERE IS HIGH CONFIDENCE THE PATTERN WILL
REMAIN TROUGHY THROUGH AT LEAST SATURDAY, THERE ARE MULTIPLE
ENSEMBLE SOLUTIONS REGARDING THE PLACEMENT OF THE PASSING TROUGH.
SOLUTIONS WITH MORE INFLUENCE FROM THE ECMWF SHOW THE TROUGH DIGGING
FURTHER SOUTH WHICH WOULD RESULT IN COOLER AND WINDIER CONDITIONS
FOR SOUTHERN CALIFORNIA WITH THE POTENTIAL FOR MARINE LAYER DRIZZLE.
SOLUTIONS THAT HAVE MORE INFLUENCE FROM THE CANADIAN AND GFS KEEP
THE LOW FURTHER NORTH, WHICH WOULD RESULT IN LESS INFLUENCE ON THE
WEATHER IN SOUTHERN CALIFORNIA OVERALL. NBM CHANCES FOR WIND GUSTS
EXCEEDING 40 MPH SATURDAY EVENING ARE 15 TO 25 PERCENT FOR THE
DESERTS, WITH CHANCES INCREASING TO 60 TO 70 PERCENT THROUGH THE
PASSES AND LOCALLY ON DESERT MOUNTAIN SLOPES.
AVIATION
212030Z....COASTS/VALLEYS...LOW CLOUDS AND FOG WILL PUSH ASHORE
AFTER 02Z AND INLAND OVERNIGHT INTO TUESDAY MORNING, GRADUALLY
FILLING MUCH OF THE COASTAL BASIN. BASES WILL BE 800-1200 FEET MSL
WITH TOPS TO 1800 FEET, WITH VIS REDUCED 1-5SM INLAND AND ON HIGHER
COASTAL TERRAIN. SCATTER OUT TUESDAY 16-18Z.
OTHERWISE...SCT HIGH CLOUDS TURNING MOSTLY CLEAR TONIGHT THROUGH
TUESDAY MORNING.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.
SKYWARN
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...CO
AVIATION/MARINE...MM
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page