693  
FXUS66 KSGX 290403  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
903 PM PDT THU AUG 28 2025  
   
SYNOPSIS  
 
SHOWERS ENDING THIS EVENING AS REMNANT TROPICAL MOISTURE MOVES OFF  
TO THE EAST. WARMER AND DRIER FRIDAY THROUGH THE WEEKEND.  
MONSOONAL MOISTURE WILL INCREASE AGAIN BY EARLY NEXT WEEK, WITH  
CHANCES FOR SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND  
DESERTS EACH AFTERNOON BEGINNING ON MONDAY. OTHERWISE WARM  
WITH HIGHS UP TO 5 DEGREES ABOVE NORMAL THROUGH THE WEEK.  
 
 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE  
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
TROPICAL MOISTURE FROM TROPICAL STORM JULIETTE BROUGHT WIDESPREAD  
RAIN ACROSS SAN DIEGO COUNTY AND PARTS OF RIVERSIDE AND SAN  
BERNARDINO COUNTIES TODAY, BUT IS NOW PUSHING EAST AND OUT OF OUR  
FORECAST AREA THIS EVENING. THE SOUTHERN SAN DIEGO COUNTY  
MOUNTAINS WERE THE BIG WINNERS WITH 0.76" AND 0.74" AT MT LAGUNA  
AND CAMERON, RESPECTIVELY, WITH DECREASING AMOUNTS TO THE NORTH  
AND WEST. A FULL LIST OF RAINFALL MEASUREMENTS IS ON OUR HOME  
PAGE. ONLY DEVIATION FROM THE PREVIOUS FORECAST IS THAT FRIDAY HAS  
TRENDED DRIER WITH MINIMAL CHANCES OF A STRAY SHOWER OVER THE  
MOUNTAINS IN THE AFTERNOON.  
 
PREVIOUS DISCUSSION...  
A WARMER AND SLIGHTLY LESS HUMID WEATHER WILL OCCUR ON FRIDAY  
WITH MOSTLY SUNNY SKIES. THERE WILL BE DRYING, BUT A WEAK AMOUNT  
OF MONSOONAL MOISTURE WILL BE AVAILABLE TO WARRANT A SLIGHT CHANCE  
FOR A SHOWER OR WEAK THUNDERSTORM TO FORM OVER THE MOUNTAINS. THE  
ATMOSPHERE CONTINUES TO DRY OUT OVER THE WEEKEND WITH PWAT VALUES  
LOWERING UNDER ONE INCH ACROSS THE LOWER DESERTS BY THE WEEKEND.  
THIS WILL DIMINISH ANY NOTABLE CHANCES FOR STORM ACTIVITY BY THE  
WEEKEND WITH ALL OTHER AREAS SEEING MOSTLY SUNNY SKIES. A WARMING  
TREND WILL ALSO OCCUR FOR AREAS AWAY FROM THE COAST DURING THIS  
TIME. HIGHS WILL BE NEAR TO SLIGHTLY ABOVE AVERAGE BY SUNDAY.  
 
MONSOONAL MOISTURE WILL INCREASE AGAIN BY LABOR DAY INTO THE MIDDLE  
OF NEXT WEEK, WHICH WILL LEAD TO A GREATER CHANCE OF SHOWER AND  
THUNDERSTORMS ACROSS THE MOUNTAINS AND DESERTS. BY TUESDAY THROUGH  
THURSDAY, CHANCES WILL BE AROUND 20-30% ACROSS THESE AREAS. A WEAK  
TROUGH OFFSHORE MAY START TO FORM SOMETIME IN THE MIDDLE OF NEXT  
WEEK, WHICH WOULD LOWER THE CHANCES FOR ANY STORMS TO OCCUR. OTHER  
AREAS WILL REMAIN QUIET WITH NEAR TO SLIGHTLY ABOVE NORMAL  
TEMPERATURES.  
 
 
   
AVIATION  
 
290300Z...SCT-BKN CLOUDS AOA 10000 FT MSL WILL SLOWLY EXIT THE  
REGION THROUGH FRIDAY MORNING. A FEW PATCHES OF COASTAL LOW CLOUDS  
VCNTY COASTAL TAF SITES WITH BASES AROUND 1000 FEET MSL. CHANCE OF  
CIG IMPACTS (LESS THAN 30 PERCENT) THROUGH 08Z FRIDAY. CUMULUS BASED  
10000 FT MSL OVER RIDGETOPS 18Z FRI TO 01Z SAT ALONG WITH A SLIGHT  
CHANCE -SHRA.  
 
 
   
MARINE  
 
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH MONDAY.  
 
 
   
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...SS/APR  
AVIATION/MARINE...KW  
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