773  
FXUS66 KSGX 221141  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
441 AM PDT TUE SEP 22 2026  
   
SYNOPSIS
 
 
HIGH TEMPERATURES WILL WARM SEVERAL DEGREES FOR TODAY AND  
WEDNESDAY TO WITHIN A FEW DEGREES OF AVERAGE ON WEDNESDAY WITH  
THE GREATEST WARMING FOR THE INLAND VALLEYS. MONSOONAL MOISTURE  
FROM THE SOUTH ON THURSDAY WILL BRING A SLIGHT CHANCE OF SHOWERS  
AND THUNDERSTORMS DURING THE AFTERNOON. DRYING ALOFT WITH NOT  
MUCH CHANGE IN TEMPERATURES FOR FRIDAY AND SATURDAY WITH A LOW  
PRESSURE SYSTEM MOVING INLAND ALONG THE WEST COAST BRINGING  
COOLING FOR SUNDAY AND MONDAY.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
   
..UPDATED AVIATION DISCUSSION
 
 
   
SHORT TERM (TODAY THROUGH THURSDAY)
 
 
A WEAK LOW PRESSURE SYSTEM WILL DEVELOP OFF THE COAST OF NORTHERN  
BAJA TODAY AND LINGER INTO THURSDAY WITH WEAK LOWER-LEVEL EASTERLY  
FLOW AND EAST WINDS FOR THE MOUNTAINS AT TIMES ON WEDNESDAY AND  
THURSDAY. HIGH TEMPERATURES FOR TODAY WILL WARM A FEW DEGREES  
NEAR THE COAST TO 5 TO LOCALLY 10 DEGREES FOR THE INLAND VALLEYS  
ONTO THE COASTAL SLOPES OF THE MOUNTAINS. SIMILAR WARMING WILL  
OCCUR AGAIN ON WEDNESDAY FROM THE COAST TO THE MOUNTAINS WITH  
WARMING ALSO SPREADING INTO THE DESERTS. THERE WILL BE LITTLE  
ADDITIONAL WARMING ON THURSDAY.  
 
HIGH TEMPERATURES ON WEDNESDAY WILL BE WITHIN A FEW DEGREES ABOVE  
OR BELOW AVERAGE FOR MOST AREAS WITH HIGH TEMPERATURES RANGING  
FROM THE MID TO UPPER 70S NEAR THE COAST TO THE UPPER 80S TO MID  
90S FOR THE INLAND EMPIRE WITH THE LOWER DESERTS AROUND 100.  
 
ON THURSDAY, THAT WEAK LOW PRESSURE SYSTEM OFF THE NORTHERN BAJA  
COAST COULD DRAW SOME MID-LEVEL MONSOONAL MOISTURE NORTHWARD INTO  
SOUTHWESTERN CALIFORNIA WITH A SLIGHT CHANCE OF SHOWERS AND  
THUNDERSTORMS FOR THE MOUNTAINS DURING THE AFTERNOON.  
 
THE MARINE LAYER IS STILL AROUND 4500 FEET DEEP WITH LOW CLOUDS  
OVER THE COASTAL WATERS EXTENDING WELL INLAND ACROSS THE COAST AND  
VALLEYS AND ONTO THE LOWER COASTAL SLOPES OF THE MOUNTAINS. THE  
MARINE LAYER IS EXPECTED TO DECREASE IN DEPTH FOR WEDNESDAY AND  
THURSDAY WITH NIGHT AND MORNING COASTAL LOW CLOUDS NOT SPREADING  
AS FAR INLAND.  
 

 
   
LONG TERM (FRIDAY THROUGH MONDAY)
 
 
THAT WEAK LOW PRESSURE SYSTEM OFF THE NORTHERN BAJA COAST WILL  
WEAKEN AND MOVE INLAND ON THURSDAY WITH DRIER WESTERLY FLOW ALOFT  
FOR FRIDAY AND SATURDAY. HIGH PRESSURE ALOFT OVER NORTHERN MEXICO  
AND SOUTHERN TEXAS WILL EXPAND WESTWARD ACROSS BAJA DURING THE  
WEEKEND WITH HURRICANE POLO REMAINING ON A WEST-NORTHWEST TRACK  
ALONG THE SOUTHERN EDGE OF THE UPPER HIGH.  
 
NOT MUCH CHANGE IN HIGH TEMPERATURES IS EXPECTED FOR FRIDAY AND  
SATURDAY WITH A LOW PRESSURE SYSTEM MOVING INLAND ACROSS THE  
WESTERN STATES BRINGING COOLING FOR SUNDAY AND MONDAY.  
 

 
   
AVIATION
 
 
221130Z...COAST/VALLEYS...LOW CLOUDS WITH BASES 3500-4000 FEET  
MSL, BUT WITH OCCASIONAL CIGS AROUND 2500 FEET, WILL CONTINUE OVER  
MOST OF THE COASTAL BASIN THIS MORNING. SCATTER OUT VCNTY KSAN  
15-17Z, AND 16-18Z ELSEWHERE. AREAS OF LOW CLOUDS BASED AROUND  
1500-2500 FEET MSL TO DEVELOP VCNTY KSAN AFTER 03Z, GRADUALLY  
SPREADING ACROSS COASTAL AREAS NORTHWARD OVERNIGHT. MOST BASES  
WILL LOWER TO AROUND 1500 FEET MSL AFTER 06Z OVERNIGHT INTO  
WEDNESDAY.  
 
OTHERWISE...MOSTLY CLEAR SKIES TODAY AND TONIGHT.  
 

 
   
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...17  
AVIATION/MARINE...MM  
 
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