122
FXUS66 KSGX 121607
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
907 AM PDT FRI SEP 12 2025
SYNOPSIS
A GRADUAL WARMING TREND WILL CONTINUE THROUGH NEXT WEDNESDAY WITH
HIGH TEMPERATURES WARMING TO AS MUCH AS 4 TO 8 DEGREES ABOVE
AVERAGE FOR THE COAST AND VALLEYS. NIGHT AND MORNING COASTAL LOW
CLOUDS WILL COVER MUCH OF THE COAST AND VALLEYS INTO SATURDAY
MORNING, THEN MOSTLY INTO THE FAR WESTERN VALLEYS AT TIMES FOR
NEXT WEEK AS THE MARINE LAYER BECOMES SHALLOWER. MONSOONAL
MOISTURE WILL RETURN NEXT WEEK WITH INCREASING CHANCES FOR
AFTERNOON AND EARLY EVENING THUNDERSTORMS FOR THE MOUNTAINS,
DESERTS, AND INLAND VALLEYS FOR WEDNESDAY THROUGH FRIDAY.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE
NO SIGNIFICANT CHANGES FROM THE PREVIOUS FORECAST. LOW CLOUDS ARE
REVERSE CLEARING THIS MORNING, WITH INLAND AREAS A BIT COOLER
TODAY AS THE CLOUDS HELP OFFSET AFTERNOON HEATING. UNCERTAINTY
WITH THE PATTERN REMAINS FOR THE LONG RANGE, ESPECIALLY WITH THE
POTENTIAL FOR MONSOONAL MOISTURE. MODELS HAVE BACKED OFF ON THE
POTENTIAL FOR PRECIPITATION ON WEDNESDAY, INDICATING NOW BETTER
CHANCES THURSDAY AND FRIDAY, ALTHOUGH THE LACK OF ALIGNMENT IN
THE UPPER LEVEL PATTERN DOESN'T BODE WELL FOR HIGH CONFIDENCE AT
THIS POINT. FOR NOW, WILL MAINTAIN THE POSSIBILITY OF
THUNDERSTORMS IN THE MOUNTAINS FOR BOTH THURSDAY AND FRIDAY
AFTERNOONS.
PREVIOUS DISCUSSION FROM 219 AM
SHORT TERM (TODAY THROUGH SUNDAY)
THE WARMING TREND WILL CONTINUE THROUGH THE WEEKEND INTO NEXT
WEEK WITH HIGH TEMPERATURES ON SUNDAY A FEW TO AROUND 5 DEGREES
BELOW AVERAGE WITH SUNDAY HIGH TEMPERATURES RANGING FROM THE LOWER
TO MID 70S NEAR THE COAST TO THE MID 80S TO LOWER 90S FOR THE
INLAND EMPIRE WITH THE MID TO UPPER 90S FOR THE LOWER DESERTS.
THE MARINE INVERSION WILL STRENGTHEN THROUGH THE WEEKEND AND
BEGIN TO LOWER FOR SATURDAY NIGHT AND SUNDAY. COASTAL LOW CLOUDS
WILL EXTEND INTO THE INLAND VALLEYS FOR TODAY AND SATURDAY, BUT
WITH GREATER COVERAGE FOR TONIGHT INTO SATURDAY MORNING. FOR
SATURDAY NIGHT INTO SUNDAY MORNING, WIDESPREAD COASTAL LOW CLOUDS
WILL SPREAD INLAND INTO THE WESTERN VALLEYS.
LONG TERM (MONDAY THROUGH THURSDAY)
THE GRADUAL WARMING TREND WILL CONTINUE THROUGH WEDNESDAY FOLLOWED
BY GRADUAL COOLING AS HIGH PRESSURE WEAKENS AND MONSOONAL MOISTURE
INCREASES. HIGH TEMPERATURES ON WEDNESDAY WILL RANGE FROM AROUND
AVERAGE FOR THE LOWER DESERTS TO 4 TO 8 DEGREES ABOVE AVERAGE FOR
THE COAST AND VALLEYS. HIGH TEMPERATURES ON WEDNESDAY WILL RANGE
FROM THE MID 70S TO LOWER 80S NEAR THE COAST TO THE MID 90S TO 102
FOR THE INLAND EMPIRE WITH 100 TO 105 FOR THE LOWER DESERTS.
THE MARINE LAYER WILL BECOME SHALLOWER WITH NIGHT AND MORNING
COASTAL LOW CLOUDS EXTENDING INLAND INTO PORTIONS OF THE WESTERN
VALLEYS AT TIMES LATE EACH NIGHT. A GRADUAL INFLUX OF MONSOONAL
MOISTURE WILL BEGIN AROUND TUESDAY AND PEAK AROUND FRIDAY WITH NBM
CHANCES FOR MEASURABLE RAINFALL FOR BIG BEAR INCREASING TO 10
PERCENT ON WEDNESDAY, 26 PERCENT ON THURSDAY, AND 33 PERCENT ON
FRIDAY.
AVIATION
121530Z...COAST/VALLEYS...LOW CLOUDS BASED 2300-3000FT MSL FILLED IN
THROUGH NEARLY THE ENTIRE COASTAL BASIN THIS MORNING WITH FAIRLY
UNIFORM COVERAGE. CLOUDS HAVE ALREADY BEGUN TO ERODE OVER THE
EASTERN VALLEYS AND MOUNTAIN FOOTHILLS, AND WILL CONTINUE TO CLEAR
EAST TO WEST OVER THE NEXT FEW HOURS, WITH CLEARING THROUGH THE
COASTAL AREAS BY 17-18Z, THOUGH SOME SPOTS COULD HOLD ONTO CIGS
THROUGH AS LATE AS 19Z. LOW CLOUDS TO REDEVELOP AND SPREAD INLAND
AGAIN AFTER 01Z SATURDAY, FIRST IN SAN DIEGO COUNTY, THEN NORTHWARD,
FILLING MOST OF THE COASTAL BASIN OVERNIGHT INTO EARLY SATURDAY
MORNING. BASES SHOULD BE AROUND 1500-2000 FEET MSL.
MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS EXPECTED TODAY
AND TONIGHT.
MARINE
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH TUESDAY.
SGX WATCHES/WARNINGS/ADVISORIES
CA...NONE.
PZ...NONE.
PUBLIC...ZUBER
AVIATION/MARINE...MUNYAN
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