284
FXUS66 KSGX 120919
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
219 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...
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
120930Z...COAST/VALLEYS...LOW CLOUDS IN SAN DIEGO COUNTY WILL
GRADUALLY DEVELOP IN ORANGE COUNTY AND PARTS OF THE INLAND EMPIRE BY
SUNRISE. BASES AROUND 2000-2300 FEET MSL WITH TOPS TO 2600 FEET WITH
VIS REDUCED 0-5SM BETWEEN THOSE ELEVATIONS. FOR PLACES WITH CIGS,
SCATTER OUT WILL OCCUR 16-18Z. LOW CLOUDS TO REDEVELOP AND SPREAD
INLAND AGAIN AFTER 01Z, FIRST IN SAN DIEGO COUNTY, THEN NORTHWARD,
FILLING MOST OF THE COASTAL BASIN OVERNIGHT INTO EARLY SATURDAY.
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.
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...17
AVIATION/MARINE...MM
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