033  
FXUS66 KSGX 230531  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
1031 PM PDT TUE SEP 22 2026  
   
SYNOPSIS
 
 
WARMER CONDITIONS FOR THE MIDDLE TO END OF THE WEEK WITH ABOVE  
AVERAGE TEMPERATURES. THE MARINE LAYER IS EXPECTED TO GET SHALLOWER  
WITH NIGHT AND MORNING LOW CLOUDS AND FOG NOT REACHING AS FAR  
INLAND. THERE IS A A SLIGHT CHANCE OF SHOWERS AND ISOLATED  
THUNDERSTORMS OVER THE MOUNTAINS THURSDAY AFTERNOON, WITH OTHERWISE  
DRY CONDITIONS EXPECTED TO PREVAIL. COOLER CONDITIONS MAY RETURN FOR  
EARLY NEXT WEEK.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
   
..UPDATED AVIATION DISCUSSION
 
 
THE MARINE LAYER IS EXPECTED TO GET SHALLOWER OVER THE NEXT FEW  
NIGHTS, STAYING MOSTLY CONFINED THE THE COAST. CONDITIONS WILL  
WARM THROUGH THE MIDDLE OF THE WEEK.  
 
WEDNESDAY, HIGH TEMPERATURES WILL WARM 5 TO 12 DEGREES FOR THE  
VALLEYS, WITH 3 TO 5 DEGREES OF WARMING ELSEWHERE. ADDITIONAL  
WARMING IS EXPECTED THROUGH SATURDAY WITH TEMPERATURES ALONG THE  
COAST WITH THE HIGHEST DEPARTURE FROM NORMAL AT 7 TO 12 DEGREES. FOR  
THE LATTER HALF OF THE WEEK, OVERNIGHT LOWS WILL INCREASE TO THE MID-  
60S TO 70 WEST OF THE MOUNTAINS AND IN THE UPPER 70S TO LOW 80S IN  
THE LOW DESERT. MODERATE HEATRISK IS EXPECTED ALONG THE COAST FRIDAY  
AND SATURDAY AND IN THE LOW DESERTS FOR THE SECOND HALF OF THE WEEK.  
MODERATE HEATRISK HAS THE MOST IMPACTS ON THOSE SENSITIVE TO HEAT,  
ESPECIALLY THOSE WITHOUT COOLING/HYDRATION. A LOW PRESSURE SYSTEM  
IS EXPECTED TO MOVE INLAND EARLY NEXT WEEK WHICH WILL BRING  
COOLING CONDITIONS AND A DEEPER MARINE LAYER.  
 
FOR THURSDAY, A CLOSED LOW LINGERING TO OUR SOUTHWEST WILL START TO  
MOVE EAST. THIS WILL DRAW MOISTURE INTO SOUTHERN CALIFORNIA FROM  
THE SOUTHEAST INCREASING CHANCES FOR PRECIPITATION, MAINLY IN THE  
MOUNTAINS. THERE REMAINS A 10% CHANCE OF THUNDERSTORMS OVER THE  
MOUNTAINS.  
 
TROPICAL CYCLONE POLO, CURRENTLY OFF THE SOUTHWEST COAST OF  
MEXICO, IS NOW A MAJOR HURRICANE. POLO IS BASICALLY STATIONARY BUT  
IS EXPECTED TO MOVE GENERALLY WEST-NORTHWEST OVER THE NEXT FEW  
DAYS. THERE REMAINS A LOT OF UNCERTAINTY IN THE FORECAST FOR LATE  
IN THE WEEKEND INTO NEXT WEEK BUT THERE COULD EVENTUALLY BE AT  
LEAST SOME PERIPHERAL IMPACTS TO PORTIONS OF SOUTHERN CALIFORNIA.  
RIGHT NOW, IT LOOKS LIKE THE MOST LIKELY IMPACTS WILL BE COASTAL  
FLOODING AND EROSION BUT THAT WILL ULTIMATELY DEPEND ON THE TRACK,  
INTENSITY, AND DURATION OF THE CYCLONE.  
 

 
   
AVIATION
 
 
230530Z...COAST...GRADUALLY INCREASING LOW CLOUDS BASED AROUND  
1500 FEET MSL OVERNIGHT, FIRST IN SAN DIEGO COUNTY, AFTER 11Z  
VCNTY KSNA. SCATTER OUT WEDNESDAY 16-18Z. LOW CLOUDS TO INCREASE  
AFTER 03Z WEDNESDAY EVE, WITH SIMILAR BASES.  
 
OTHERWISE...MOSTLY CLEAR SKIES WITH UNRESTRICTED VIS THROUGH  
WEDNESDAY.  
 

 
   
MARINE
 
 
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH SUNDAY.  
 

 
   
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...ZUBER  
AVIATION/MARINE...MM  
 
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