788
FXUS66 KSGX 131506
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
806 AM PDT SAT SEP 13 2025
SYNOPSIS
NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES THROUGH MONDAY. A SLOW
WARMING TREND WILL BRING A MORE SHALLOW MARINE LAYER AND NEAR
NORMAL TO ABOVE NORMAL TEMPERATURES BY WEDNESDAY. MONSOONAL
MOISTURE MAY RETURN FOR THE LATTER HALF OF THE WEEK, WITH
THUNDERSTORM CHANCES MAINLY IN THE MOUNTAINS.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
UPDATE
CLOUDS FILLED IN VERY SUFFICIENTLY THIS MORNING, WHICH MAY BRING
SLIGHTLY COOLER THAN FORECASTED TEMPERATURES FOR THE AFTERNOON
SHOULD THE BURN OFF BE SLOW. MORE SEASONABLE TO SLIGHTLY ABOVE
NORMAL TEMPERATURES ARE STILL EXPECTED TO RETURN BY
TUESDAY/WEDNESDAY, ALTHOUGH INCREASING MOISTURE ACROSS THE
DESERTS MAY HINDER SOME WARMING THERE. THUNDERSTORM CHANCES STILL
LOOK FAVORABLE FOR THURSDAY AND FRIDAY, PRIMARILY IN THE
MOUNTAINS, WITH LESSER CONFIDENCE IN THE URBAN, VALLEYS, AND
DESERTS.
PREVIOUS DISCUSSION FROM 239 AM
THIS MORNING...THE MARINE LAYER IS 2500-3000 FT DEEP AND LOW
CLOUDS HAVE SPREAD INLAND TO THE FOOTHILLS OF SAN DIEGO COUNTY.
THE LOW CLOUDS WILL CONTINUE TO INCREASE IN COVERAGE UNTIL ABOUT 8
AM BEFORE BEGINNING TO SCATTER OUT. THE INVERSION STRENGTH IS
SIMILAR TO YESTERDAY SO THE CLEARING SHOULD FOLLOW MUCH THE SAME
TIMING AS YESTERDAY. ELSEWHERE, SKIES WILL REMAIN CLEAR.
NUMERICAL MODELS REMAIN IN GOOD AGREEMENT THROUGH TUESDAY WITH
RESPECT TO THE PLACEMENT AND TIMING OF SYNOPTIC-SCALE SYSTEMS.
THE EXTENSIVE LOW/TROUGH OVER THE WESTERN US WILL MOVE EAST WITH
THE UPPER TROUGH AXIS REACHING THE ROCKIES BY SUNDAY MORNING. A
WEAK RIDGE WILL FOLLOW THE TROUGH OVER THE WEST COAST FOR MONDAY
THROUGH WEDNESDAY WITH A WEAK UPPER LEVEL LOW OFF THE COAST OF
SOCAL BY TUESDAY. DAYTIME HIGH TEMPERATURES WILL REMAIN BELOW
SEASONAL AVERAGES THROUGH SUNDAY BEFORE WARMING UP FOR MONDAY
THROUGH WEDNESDAY AS THE WEAK RIDGE BRINGS HEIGHT RISES.
WEDNESDAY WILL LIKELY BE THE WARMEST DAY WITH HIGH TEMPERATURES
FROM 1 TO 7 DEGREES ABOVE SEASONAL AVERAGES IN MOST AREAS. THE
MARINE LAYER WILL MAINTAIN ITS CURRENT DEPTH THROUGH SUNDAY
MORNING WITH THE NIGHTTIME LOW CLOUDS SPREADING INLAND TO THE
FOOTHILLS. THE MARINE LAYER WILL THEN BECOME SHALLOWER FOR MONDAY
THROUGH WEDNESDAY LIMITING THE LOW CLOUDS TO THE COASTAL AREAS AND
WESTERN PORTIONS OF THE VALLEYS.
FOR THE LATTER HALF OF NEXT WEEK...THE MODEL SOLUTIONS BEGIN TO
DIVERGE, INTRODUCING MORE UNCERTAINTY INTO THE FORECAST. IN SPITE
OF THE UNCERTAINTY, IT'S LIKELY THAT WITH A WEAK UPPER LOW OFF
THE SOCAL COAST AND A RIDGE TO THE EAST SOME MOISTURE WILL BE
DRAWN NORTHWARD FROM THE TROPICS. THIS WILL BRING CHANCES FOR
SHOWERS AND POSSIBLY TSTMS THU-SAT. THE MOISTURE WILL ALSO
RESTRICT THE WARMING AND DAYTIME TEMPS WILL TREND LOWER WITH
SATURDAY TEMPS RETURNING TO NEAR OR A LITTLE BELOW SEASONAL
AVERAGES.
AVIATION
131500Z...COAST/VALLEYS...LOW MARINE CLOUDS HAVE FILLED IN THROUGH
THE ENTIRE COASTAL BASIN THIS MORNING THROUGH TO THE MOUNTAIN
FOOTHILLS. BASES ARE GENERALLY 1800-2300FT MSL BUT SHOULD CONTINUE
TO GRADUALLY LIFT TO 2100-2600FT MSL OVER THE NEXT FEW HOURS. THESE
CLOUDS ARE EXPECTED TO SCATTER FROM THE INLAND VALLEYS 16-17Z, THEN
FROM MOST COASTAL AREAS 17-19Z, THOUGH SOME PATCHY LOW CLOUDS WILL
LIKELY REMAIN ALONG THE IMMEDIATE SAN DIEGO COUNTY COAST THROUGH
ABOUT 21Z. KSAN (AND, TO A LESSER EXTENT, KCRQ) HAS ABOUT A 40%
CHANCE TO SEE OCCASIONAL BKN CIGS THROUGH THIS TIME. CLOUDS WITH
LOWER BASES 1500-2000 FT MSL TO PUSH BACK INLAND AFTER 02Z SUN,
MOVING INLAND 20-25 MILES.
MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS THROUGH SUNDAY
MORNING.
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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