311
FXUS66 KSGX 300618
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
1118 PM PDT SAT AUG 29 2026
SYNOPSIS
GRADUAL COOLING TREND THROUGH THE MIDDLE OF THE UPCOMING WEEK. FOR
TUESDAY AND WEDNESDAY, INCREASED HIGH CLOUD COVER IS LIKELY ALONG
WITH A 15 TO 25 PERCENT CHANCE OF LIGHT PRECIPITATION AS MOISTURE
FROM TROPICAL CYCLONE KARINA POTENTIALLY GETS PULLED NORTHWARD. THIS
TROPICAL SYSTEM IS FORECAST TO REMAIN WELL TO OUR SOUTH. GRADUAL
WARMING FOR THE LATTER HALF OF NEXT WEEK. NIGHT AND MORNING LOW
CLOUDS WILL BE MORE WIDESPREAD FOR THE UPCOMING WEEK, REACHING INTO
THE WESTERN VALLEYS AT TIMES.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
WHILE HIGH TEMPERATURES TODAY WILL REMAIN 3 TO 7, LOCALLY UP TO 12
DEGREES ABOVE AVERAGE THEY'RE FORECAST TO BE 3 TO 5 DEGREES COOLER
THAN YESTERDAY. THAT COOLING TREND WILL CONTINUE THROUGH TUESDAY
OR WEDNESDAY FOR MOST LOCATIONS. BY WEDNESDAY, HIGH TEMPERATURES
ARE EXPECTED TO BE 3 TO 7 DEGREES BELOW AVERAGE FOR THIS TIME OF
YEAR. ADDITIONALLY, MARINE LAYER LOW CLOUDS AND AREAS OF FOG WILL
BECOME MORE PREVALENT ALONG THE COAST AND IN THE WESTERN VALLEYS
AT TIMES.
MOISTURE FROM TROPICAL CYCLONE KARINA MAY BE PULLED INTO SOUTHERN
CALIFORNIA BY MID-WEEK. THERE IS HIGH CONFIDENCE THIS WILL
INCREASE HIGH CLOUD COVERAGE ACROSS THE AREA, WITH LESSER
CONFIDENCE IN CHANCES OF LIGHT RAIN. CURRENT FORECAST HAS PULLED
RAINFALL CHANCES BACK FOR MUCH OF WEDNESDAY, LEAVING THE HIGHEST
CHANCES ON TUESDAY AT 15-25 PERCENT. MODEL GUIDANCE STILL IS YET
TO ALIGN ON THE AMOUNT OF MOISTURE THAT MOVES INTO OUR AREA. THE
EC CONTINUES TO TREND DRIER THAN THE GFS/CANADIAN. HOW THE
TROPICAL CYCLONE TRACKS WILL ULTIMATELY BE THE BIGGEST INFLUENCE
IN MOISTURE INFLUX, WITH A MORE WESTERLY TRACK BEING DRIER FOR US
AND A MORE EASTERLY TRACK BEING WETTER. CURRENT FORECAST CLOSELY
FOLLOWS THE NBM.
THURSDAY INTO NEXT WEEKEND, THE UPPER LEVEL HIGH BEGINS TO SHIFT
BACK WESTWARD, BRINGING WARMING AND THE POTENTIAL RETURN OF MONSOON
MOISTURE. HIGH TEMPERATURES RETURN TO NEAR AVERAGE BY FRIDAY.
AVIATION
300600Z...COAST...PATCHY LOW CLOUDS CONTINUE NEAR THE COAST,
BECOMING MORE WIDESPREAD AND MOVING INLAND AFTER ABOUT 09Z.
INTERMITTENT CIGS AT COASTAL TAF SITES WITH HIGHEST CONFIDENCE FOR A
FEW HOURS OF IFR CIGS AT KSAN (70-80%) AND KCRQ (50%) BY 12Z. THERE
IS ONLY ABOUT A ~30% CHANCE OF CIGS REACHING COASTAL ORANGE COUNTY
(KSNA) FOR 12-16Z. BASES ARE EXPECTED TO BE AROUND 600-1000FT MSL.
VIS DOWN TO 2-5SM FOR POCKETS OF THE COAST AND VALLEYS, LOCALLY DOWN
TO 1/2SM FOR ELEVATED COASTAL TERRAIN. ANY CLOUDS THAT MOVE INLAND
WILL SCATTER BACK TO THE COAST BY 16-17Z, WITH SKC THEREAFTER.
CLOUDS WITH SLIGHTLY HIGHER BASES WILL FORM AND MOVE INTO COASTAL
REGIONS AFTER 06Z MON.
MTNS/DESERTS
OCCASIONAL FEW HIGH LVL CLOUDS AOA 20,000FT MSL
THROUGH THE PERIOD. BREEZY WEST TO SOUTHWEST WINDS 20Z SUN TO ABOUT
05Z MON ON THE DESERT SLOPES INTO THE DESERTS, WITH GUSTS TO 25-40
KTS.
MARINE
GUSTS AROUND 20 KNOTS EXPECTED EACH AFTERNOON THROUGH MONDAY IN THE
VICINITY OF SAN CLEMENTE ISLAND. OTHERWISE, NO HAZARDOUS MARINE
CONDITIONS ARE EXPECTED THROUGH THURSDAY.
BEACHES
A 3-FOOT SWELL FROM THE SOUTH-SOUTHWEST (200 DEGREES) AT 15-17
SECONDS WILL PERSIST INTO SUNDAY. THIS WILL BRING LOCALIZED ELEVATED
SURF OF 3-5 FEET WITH SETS TO 6 FEET, ALONG WITH A HIGH RIP CURRENT
RISK TO SOUTHWEST-FACING BEACHES, MOSTLY IN NORTH SAN DIEGO COUNTY
AND ORANGE COUNTY. A NEW PULSE OF SOUTHERLY SWELL (180-190 DEGREES)
FROM TROPICAL STORM KARINA WILL KEEP SURF ELEVATED AT 3-6 FEET FOR
MONDAY THROUGH WEDNESDAY.
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...STEWEY
AVIATION/MARINE/BEACHES...CSP
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