484  
FXUS66 KSGX 202026  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
126 PM PDT FRI JUN 20 2025  
   
SYNOPSIS  
 
GUSTY WESTERLY WINDS OVER THE MOUNTAINS AND INTO THE DESERTS THROUGH  
SATURDAY WITH COOLER CONDITIONS AND A MORE EXTENSIVE MARINE LAYER  
LOW CLOUD COVERAGE. WEAK OFFSHORE FLOW SUNDAY WILL BRING  
TEMPERATURES UP A FEW DEGREES. BELOW AVERAGE TEMPERATURES WILL  
CONTINUE EARLY IN THE WEEK, WITH A GRADUAL WARMING FOR THE MIDDLE TO  
END OF THE WEEK.  
 
 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE  
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
FOR THE WEEKEND, AN UPPER LEVEL LOW OFF THE COAST OF BRITISH  
COLUMBIA WILL DIG SOUTHEAST INTO THE GREAT BASIN. THIS WILL BRING 5  
TO 15 DEGREE BELOW AVERAGE TEMPERATURES FROM THE COAST TO THE  
DESERTS SATURDAY. IN ADDITION, GUSTY WESTERLY WINDS CAN BE EXPECTED  
OVER THE MOUNTAINS AND INTO THE DESERTS THIS AFTERNOON AND EVENING  
AND AGAIN SATURDAY AFTERNOON AND EVENING. WINDS WILL BE STRONGEST  
THROUGH THE SAN GORGONIO PASS WHERE GUSTS 55 TO 60 MPH ARE POSSIBLE,  
OTHERWISE GUSTS WILL BE 40 TO 50 MPH.  
 
MARINE LAYER LOW CLOUDS AND AREAS OF FOG WILL BE PERSISTENT INTO  
NEXT WEEK, WITH VARYING DEPTH. THE MARINE LAYER IS EXPECTED TO  
DEEPEN SLIGHTLY SATURDAY, ALTHOUGH THE AMOUNT OF DEEPENING WILL  
DEPEND ON THE POSITION OF A POTENTIAL EDDY. AS THE UPPER LEVEL LOW  
DIGS INTO THE GREAT BASIN SUNDAY, THE PRESSURE GRADIENT WILL BRIEFLY  
TURN OFFSHORE BRINGING AN UPTICK IN NORTHEASTERLY WINDS SUNDAY  
MORNING. THOSE OFFSHORE WINDS LOOK TO STAY ON THE WEAKER SIDE, BUT  
HAVE THE POTENTIAL TO INHIBIT LOW CLOUDS REACHING PORTIONS OF THE  
INLAND EMPIRE AND NEAR MOUNTAIN FOOTHILLS.  
 
A SECONDARY LOW WILL DEVELOP IN THE MEAN TROUGH SUNDAY NIGHT INTO  
MONDAY AND DIGS TOWARDS SOUTHERN CALIFORNIA BEFORE PROGRESSING  
WESTWARD ON TUESDAY. THIS WILL MAINTAIN COOLER WEATHER WITH HIGHS 5  
TO 10 DEGREES BELOW NORMAL THROUGH TUESDAY AND MARINE LAYER LOW  
CLOUDS SPREADING INTO THE WESTERN VALLEYS EACH NIGHT. FOR WEDNESDAY  
THROUGH THE END OF NEXT WEEK, THE UPPER LEVEL TROUGHING SHIFTS NORTH  
RESULTING IN A GRADUAL WARMING AND LESS EXTENSIVE NIGHT AND MORNING  
LOW CLOUDS. CURRENT FORECAST FOR THE END OF THE WEEK FOLLOWS NBM  
WITH HIGHS WITHIN A FEW DEGREES OF NORMAL.  
 
 
   
AVIATION  
 
202030Z....COAST/VALLEYS...INTERMITTENT CIGS ALONG IMMEDIATE COAST  
BEFORE LOW CLOUDS BEGIN TO MARCH INLAND AFTER 01Z. BASES WILL BE  
1600-2000 FEET MSL WITH TOPS TO 3200 FEET SHOULD EVENTUALLY FILL THE  
COASTAL BASIN BY 13Z SATURDAY. VIS 1-5SM FAR INLAND. SCATTER OUT  
SATURDAY 17-20Z.  
   
MOUNTAINS/DESERTS  
CLEAR SKIES AND UNRESTRICTED VIS THROUGH  
SATURDAY. WESTERLY WINDS WITH GUSTS 25-45 KNOTS THROUGH MOUNTAIN  
PASSES AND LOCALLY INTO DESERTS, LIKELY PRODUCING POCKETS OF  
UP/DOWNDRAFTS IN LEE OF MOUNTAINS/MOUNTAIN PASSES IN ADDITION TO  
ISOLD BLDU IN THE DESERT WITH VIS 3-5SM AT TIMES. A SLIGHT DECREASE  
SATURDAY MORNING.  
 
 
   
MARINE  
 
NORTHWEST WIND GUSTS 20-25 KNOTS NEAR SAN CLEMENTE ISLAND THIS  
AFTERNOON AND EVENING. OTHERWISE, NO HAZARDOUS MARINE CONDITIONS ARE  
EXPECTED THROUGH WEDNESDAY.  
 
 
   
SKYWARN  
 
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE  
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.  
 
 
   
SGX WATCHES/WARNINGS/ADVISORIES  
 
CA...WIND ADVISORY UNTIL 11 PM PDT SATURDAY FOR APPLE AND LUCERNE  
VALLEYS.  
 
WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 11 PM PDT SATURDAY FOR  
SAN DIEGO COUNTY DESERTS.  
 
WIND ADVISORY UNTIL 11 PM PDT SATURDAY FOR SAN GORGONIO PASS  
NEAR BANNING.  
 
PZ...NONE.  
 
 
 
 
 
PUBLIC...CO  
AVIATION/MARINE...MM  
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