100
FXUS66 KSGX 122022
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
122 PM PDT FRI SEP 12 2025
SYNOPSIS
BELOW NORMAL TEMPERATURES INTO THE WEEKEND BEFORE A SLOW WARMING
INTO MIDDLE OF NEXT WEEK. A DEEPER MARINE LAYER PERSISTS INTO
SUNDAY MORNING BEFORE BECOMING MORE SHALLOW INTO WEDNESDAY.
THUNDERSTORM CHANCES RETURN FOR THE MOUNTAINS AS MONSOONAL
MOISTURE MOVES IN FOR THE LATTER HALF OF THE WEEK, WITH LOWER
CHANCES FOR THE VALLEYS AND DESERTS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
WATER VAPOR SATELLITE IMAGERY SHOWS AN UPPER LEVEL LOW OVER CENTRAL
CALIFORNIA, RESPONSIBLE FOR THE WELL-BELOW NORMAL TEMPERATURES WE'VE
ENJOYED THE PAST SEVERAL DAYS. HIGHS TODAY WILL BE SIMILAR TO
YESTERDAY, WITH TEMPERATURES IN THE LOW 70S TO LOW 80S FOR COASTAL
AND INLAND AREAS, 60S FOR THE MOUNTAINS, AND 90S FOR THE DESERTS.
LATER TODAY, THE LOW WILL BEGIN TO PUSH EASTWARD INTO THE FOUR
CORNERS WHILE A WEAK RIDGE BUILDS OVER THE WEST COAST. DESPITE THE
THERMAL RIDGE AXIS SETTING UP OVER THE REGION, TEMPERATURES LOOK TO
ONLY WARM A FEW DEGREES ON SATURDAY AS A SHORTWAVE TROUGH OFF THE
COAST POSITIONS JUST WEST OF POINT CONCEPTION. THIS TROUGH WILL
MODERATE THE WARM UP SATURDAY AND A BIT ON SUNDAY, WHILE ALSO
HELPING MAINTAIN A DEEPER MARINE LAYER INTO AT LEAST SUNDAY
MORNING.
EARLY TO MID WEEK, THE RIDGE SHIFTS INTO THE COLORADO RIVER VALLEY
AND THE AFOREMENTIONED SHORTWAVE BECOMES A CLOSED LOW AND SITS OFF
THE COAST OF CENTRAL CALIFORNIA. THIS PATTERN WILL ALLOW FOR SOME
MONSOONAL MOISTURE TO START PUSHING UP INTO THE DESERT SOUTHWEST FOR
THE LATTER HALF OF THE WEEK WHILE TEMPERATURES CONTINUE TO WARM
WITH THE RIDGE DISPLACED TO THE EAST. INCREASING HEIGHTS WILL LEAD
TO A SHALLOWER MARINE LAYER, WITH LIMITED INLAND EXTENT AFTER
MONDAY. TEMPERATURES WILL BE ABLE TO SUFFICIENTLY WARM FOR INLAND
AND MOUNTAIN AREAS NO LONGER BENEFITING FROM A MORNING MARINE
LAYER, WHILE THE DESERTS LOOK TO WARM A LITTLE SLOWER GIVEN THE
UPTICK IN MOISTURE FROM THE SOUTH. BY TUESDAY, HIGHS WILL RETURN
TO AROUND 5 DEGREES ABOVE-NORMAL FOR INLAND REGIONS, REMAINING
NEAR NORMAL FOR THE DESERTS. TEMPERATURES PEAK ON WEDNESDAY IN THE
UPPER 70S TO UPPER 90S FOR THE COASTS AND INLAND AREAS, 70S AND
80S FOR THE MOUNTAINS, AND 102-105F FOR THE DESERTS.
FOR THE LATTER HALF OF THE WEEK, MODELS CONTINUE TO DIFFER ON THE
UPPER LEVEL PATTERN. MOST AGREE WITH THE INFLUX OF MONSOONAL
MOISTURE WITH THE RIDGE OVER THE FOUR CORNERS AND LOW OFF THE COAST,
BUT NEWER RUNS SHOW A DEEPENING LOW OVER THE PACNW TRAVERSING
SOUTHWARD AND HELPING TO FLATTEN THE RIDGE ON THURSDAY. IF THIS
OCCURS, MORE ZONAL FLOW WILL ENSUE WITH COOLER WEATHER INTO THE END
OF THE WEEK. THIS COULD LIMIT THUNDERSTORM CHANCES FOR THE MOUNTAINS
AND DESERTS THURSDAY AND FRIDAY, CURRENTLY HOVERING AROUND 20-40%
CHANCE EACH AFTERNOON. THIS WILL BE SOMETHING TO KEEP AN EYE ON
IN THE COMING DAYS, WITH BOTH TEMPERATURES AND MOISTURE KEY
PLAYERS INTO WHETHER STORMS DEVELOP ON THE BACK END OF NEXT WEEK.
AVIATION
122015Z...COAST/VALLEYS...ASIDE FROM A FEW STRAY CLOUDS BASED AT
2800-3200FT MSL, MOSTLY CLEAR SKIES PREVAIL THROUGH THE AFTERNOON.
LOW CLOUDS BASED INITIALLY 2200-2500FT MSL WILL BEGIN TO REDEVELOP
AND SPREAD INLAND AGAIN AFTER 01Z SATURDAY, WITH BASES SETTLING TO
AROUND 1600-2000FT MSL AFTER 06-08Z. COVERAGE IS EXPECTED TO BE
SOMEWHAT PATCHY AND FAVORED ACROSS COASTAL SAN DIEGO COUNTY
INITIALLY, BUT WILL EVENTUALLY BECOME MORE UNIFORM IN COVERAGE AND
SPREAD NORTHWARD THROUGH ORANGE COUNTY AND INTO THE INLAND VALLEYS
THROUGH 09-12Z SATURDAY. CLOUDS BEGIN TO SCATTER OUT 15-17Z SATURDAY
MORNING FOR THE INLAND VALLEYS, CLOSER TO 17-19Z FOR THE IMMEDIATE
COASTS.
MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS EXPECTED TODAY
AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH WEDNESDAY
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...ZUBER
AVIATION/MARINE...MUNYAN
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