618  
FXUS66 KSGX 282039  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
139 PM PDT MON JUL 28 2025  
   
SYNOPSIS
 
 
A STABLE WEATHER PATTERN WILL CONTINUE ACROSS THE REGION WITH A  
TROUGH TO THE NORTH AND HIGH PRESSURE TO THE SOUTH. THIS WILL KEEP  
TEMPERATURES NEAR NORMAL THROUGH THE WEEK WITH DRY WEATHER. THE  
MARINE LAYER WILL HELP TO BRING IN LOW CLOUDS FOR THE COAST AND  
WESTERN VALLEYS EACH NIGHT AND MORNING.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
SOCAL IS CURRENTLY IN BETWEEN TWO LARGE PRESSURE SYSTEMS ACROSS  
NORTH AMERICA: ONE DOMINANT RIDGE OF HIGH PRESSURE OVER THE  
SOUTHERN PLAINS BRINGING RELENTLESS HEAT AND AN AREA OF LOW  
PRESSURE IN THE GULF OF ALASKA, BRINGING COOL AND WET CONDITIONS  
TO THE NORTHERN WEST COAST. THIS HAS BROUGHT US INTO A WEAK  
TROUGHING PATTERN, WHICH WILL CONTINUE TO BRING VERY BENIGN  
WEATHER THIS WEEK. HIGH PRESSURE ACROSS THE SOUTHERN PLAINS WILL  
EXPAND FURTHER WEST INTO BAJA CALIFORNIA, REMAINING THERE THROUGH  
THE WEEK AS BROAD TROUGHING STICKS OVER THE WEST. THIS WILL LEAD  
TO VERY MINOR DAY TO DAY CHANGES IN THE WEATHER PATTERN FROM  
TUESDAY INTO THE END OF THE WEEK. THE MARINE LAYER WILL THIN  
SLIGHTLY BY THE MIDDLE OF THE WEEK, KEEPING NIGHT AND MORNING LOW  
CLOUDS CONFINED TO THE COAST AND VALLEYS OF SAN DIEGO AND ORANGE  
COUNTIES. DIURNAL SOUTH AND WEST WINDS WILL OCCUR ACROSS THE  
DESERT SLOPES AND DESERTS, MAINLY BELOW 35 MPH EACH DAY.  
 
ENSEMBLE MODELS SHOW MODEST AGREEMENT ON THE RIDGE TO THE SOUTH  
BECOMING A BIT STRONGER BY THE WEEKEND, WHICH WOULD LEAD TO A  
SUBTLE RISE IN TEMPERATURES. HOWEVER, MODELS SHOW THIS MAY NOT  
LAST TOO LONG AS THE TROUGH TO THE NORTH MAY BE FAVORED BY EARLY  
NEXT WEEK. ENSEMBLE MODELS ALSO SHOW A POTENTIAL INCREASE IN  
PRECIPITABLE WATER AMOUNTS BY THE EARLY TO MIDDLE PORTION OF NEXT  
WEEK, WHICH COULD BRING A NON ZERO CHANCE OF MONSOON THUNDERSTORMS  
INTO THE PICTURE IF HIGH PRESSURE SETS UP OVER THE SOUTHWEST.  
THIS IS STILL QUITE A WAYS OUT, SO CONTINUE TO MONITOR THE  
FORECAST FOR UPDATES.  
 

 
   
AVIATION
 
 
282030Z....COAST/WESTERN VALLEYS...LOW CLOUDS TO PUSH ASHORE AFTER  
02Z AND LOCALLY INTO WESTERN VALLEYS AFTER 06Z. BASES SHOULD BE 1200-  
1600 FEET MSL, TOPS TO 2000 FEET, AND LOCAL VIS REDUCED 1-5SM ON  
HIGHER TERRAIN. SCATTER OUT TUESDAY 15-17Z.  
   
INLAND VALLEYS/MOUNTAINS/DESERTS
 
MOSTLY CLEAR WITH VFR CONDITIONS  
THROUGH TUESDAY.  
 

 
   
MARINE
 
 
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SATURDAY.  
 

 
   
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...APR  
AVIATION/MARINE...MM  
 
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