003
FXUS66 KSGX 302309
AFDSGX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
409 PM PDT SUN AUG 30 2026
SYNOPSIS
GRADUAL COOLING TREND THROUGH THE MIDDLE OF THE UPCOMING WEEK. FOR
TUESDAY AND WEDNESDAY, INCREASED HIGH CLOUD COVER CONTINUES TO LOOK
LIKELY, BUT PRECIPITATION CHANCES HAVE DECREASED. GRADUAL WARMING
FOR THE LATTER HALF OF NEXT WEEK, WITH TEMPERATURES REMAINING NEAR
OR SLIGHTLY ABOVE AVERAGE. NIGHT AND MORNING COASTAL LOW CLOUDS
EXPECTED MOST MORNINGS THIS WEEK, REACHING INTO THE WESTERN VALLEYS
AT TIMES. WE'RE MONITORING THE POTENTIAL FOR WIDESPREAD
PRECIPITATION OVER LABOR DAY WEEKEND, HOWEVER THERE IS HIGH
UNCERTAINTY IN HOW THE FORECAST WILL EVOLVE.
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
..UPDATED AVIATION DISCUSSION
AT 11 AM, TEMPERATURES WERE RUNNING 2 TO 8 DEGREES COOLER THAN
THEY WERE AT THAT TIME YESTERDAY ACROSS THE AREA. A GRADUAL
COOLING IS EXPECTED EACH DAY THROUGH TUESDAY, WITH MINOR WARMING
EXPECTED FOR THE LATTER HALF OF THE WEEK. EVEN WITH THE WARMING,
TEMPERATURES ARE EXPECTED TO STAY NEAR TO SLIGHTLY ABOVE AVERAGE
FOR THIS TIME OF YEAR.
BROAD TROUGHING IS EXPECTED PREVAIL OVER THE WESTERN UNITED STATES
THROUGH AT LEAST THE MIDDLE OF THE WEEK, WHICH WILL KEEP THE FLOW
ALOFT SOUTHWESTERLY AND CUT DOWN THE HUMIDITY. IN ADDITION, WINDS
WILL INCREASE EACH AFTERNOON WITH THE SEA BREEZE, MOST NOTICEABLE
FOR MOUNTAINS, PASSES, AND CANYONS. LATEST FORECAST HAS BACKED OFF
ON PRECIPITATION FROM TROPICAL CYCLONE KARINA, WITH CURRENT CHANCES
NOW LESS THAN 15 PERCENT. THE MOST LIKELY SCENARIO IS THERE WILL BE
MORE WIDESPREAD HIGH CLOUD COVERAGE TUESDAY INTO WEDNESDAY. THE
MARINE LAYER IS EXPECTED TO CONTINUE TO REBUILD OVER THE NEXT FEW
DAYS, WITH THE POTENTIAL FOR NIGHT AND MORNING LOW CLOUDS TO REACH
INTO THE WESTERN VALLEYS. DEPENDING ON THE EXTENT OF HIGH CLOUD
COVERAGE MID-WEEK, LOW CLOUD COVERAGE MAY BE DISRUPTED AGAIN.
LATE IN THE WEEK, ENSEMBLES BEGIN TO DIVERGE ON THE PLACEMENT OF THE
UPPER TROUGH NEAR THE WEST COAST AND THE UPPER HIGH OVER THE
SOUTHERN ROCKIES, WITH A TREND TOWARDS A MORE EASTWARD PLACEMENT OF
EACH. THIS MORE EASTWARD PLACEMENT OF THE RIDGE AND TROUGHING CLOSER
TO THE COAST WOULD LIMIT THE AMOUNT OF WARMING LATE IN THE WEEK INTO
NEXT WEEKEND. THIS WOULD ALSO AFFECT THE STEERING FLOW OF A
POTENTIAL TROPICAL SYSTEM AND ANY MOISTURE AND PRECIPITATION WE'D
RECEIVE FROM IT OVER THE WEEKEND INTO EARLY NEXT WEEK. WHILE THE
NATIONAL HURRICANE CENTER HAS A 90% CHANCE OF THIS DISTURBANCE
DEVELOPING INTO A TROPICAL CYCLONE OFF THE COAST OF MEXICO IN THE
NEXT 7 DAYS, IT IS FAR TOO EARLY TO TELL WHAT, IF ANY, IMPACTS WE'LL
SEE LOCALLY, ESPECIALLY GIVEN THE ENSEMBLE SPREAD IN THE UPPER LEVEL
PATTERN. CURRENT FORECAST HAS AT LEAST A CHANCE OF PRECIPITATION
NEXT WEEKEND.
AVIATION
310000Z...COASTS/VALLEYS...LOW CLOUDS WILL BEGIN TO REFORM AND
GATHER THIS EVENING AND FILL IN, WITH DEVELOPING CIGS EXPECTED
ACROSS COASTAL SAN DIEGO COUNTY BY 05-06Z. OVERNIGHT, LOW CLOUDS
EXPECTED TO FILL INLAND THROUGH ABOUT 15 MILES, WITH PATCHY CIGS
SPREADING INTO ORANGE COUNTY AFTER 09Z. THERE IS ABOUT A 60% CHANCE
OF CIGS IMPACTING KSNA BETWEEN 11-16Z MONDAY. VIS RESTRICTIONS
LIMITED TO WHERE CLOUDS INTERSECT HIGHER TERRAIN. CLOUDS SCATTER OUT
BY 16-17Z. CLOUDS WILL REGATHER AND FILL BACK IN BEGINNNING AROUND
01-03Z TUE AROUND THE COASTAL AREAS OF SAN DIEGO AND CONTINUE TO
FILL BACK IN ALONG THE COASTAL SITES THROUGH THE REST OF THE
FORECAST PERIOD.
MTNS/DESERTS
OCCASIONAL FEW LOW CLOUDS AROUND 10,000 FT DURING
THE AFTERNOON HOURS, AND HIGH LVL CLOUDS AOA 20,000FT MSL THROUGH
THE PERIOD. BREEZY WEST TO SOUTHWEST WINDS 20Z THIS AFTERNOON TO
ABOUT 05Z MONDAY FOR THE DESERT SLOPES INTO THE DESERTS, WITH GUSTS
TO 20-30 KTS, LOCALLY UP TO 35-40 KTS THROUGH PASSES.
MARINE
GUSTS AROUND 20 KNOTS EXPECTED EACH AFTERNOON THROUGH THURSDAY IN
THE VICINITY OF SAN CLEMENTE ISLAND. LOCALIZED GUSTS NEAR THE ISLAND
MAY REACH 25 KTS ON TUESDAY/WEDNESDAY AFTERNOONS. OTHERWISE, NO
HAZARDOUS MARINE CONDITIONS ARE EXPECTED.
BEACHES
A 3-FOOT SWELL FROM THE SOUTH-SOUTHWEST (200 DEGREES) AT 15 SECONDS
WILL PERSIST THROUGH THIS EVENING. 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 SOUTHERLY SWELL (180-190 DEGREES)
FROM HURRICANE KARINA WILL KEEP SURF ELEVATED AT 3-5 FEET WITH SETS
TO 6 FEET FOR MONDAY THROUGH WEDNESDAY. CONTINUED TROPICAL SWELLS
LOOK TO KEEP SURF ELEVATED THROUGH THE END OF THE WEEK AS WELL.
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...CO
AVIATION/MARINE/BEACHES...STEWEY
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