413  
FXUS66 KSGX 012014  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
114 PM PDT WED OCT 1 2025  
   
SYNOPSIS  
 
A TROUGH WILL MOVE INTO THE WEST COAST, BRINGING BELOW NORMAL  
TEMPERATURES AND BREEZY WEST WINDS ACROSS THE MOUNTAINS AND THE  
DESERTS BY THURSDAY AND FRIDAY. THE TROUGHING PATTERN WILL STICK  
AROUND INTO THE WEEKEND AND EARLY NEXT WEEK WITH LESS WIND AND  
COOLER THAN NORMAL TEMPERATURES. LOW CLOUDS WILL ALSO BECOME MORE  
EXTENSIVE WEST OF THE MOUNTAINS EACH NIGHT INTO LATER IN THE WEEK  
AS WELL. A SUBTLE WARMING TREND IS SLATED FOR THE MIDDLE OF NEXT  
WEEK.  
 
 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE  
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
CRYSTAL CLEAR SKIES ARE SEEN ACROSS SOCAL THIS AFTERNOON. A  
TROUGHING PATTERN IS PRESENT OVER THE WEST COAST AS A LARGE AREA  
OF LOW PRESSURE LOOMS OFF OF THE COAST OF THE PACIFIC NORTHWEST.  
THIS TROUGH WILL ELONGATE FURTHER SOUTH OVER OUR REGION BY  
THURSDAY INTO FRIDAY. SIMILAR TEMPERATURES WILL BE EXPECTED  
TOMORROW, THOUGH WEST WINDS WILL INCREASE SLIGHTLY OVER DESERT  
FACING MOUNTAIN PASSES NEAR 20-35 MPH AS THE MARINE LAYER BEGINS  
TO BUILD WITH LOW CLOUDS MORE PREVALENT ACROSS THE COASTAL AREAS.  
THE MAIN AXIS OF THE TROUGH WILL PASS THROUGH OUR REGION BY  
FRIDAY, BRINGING COOLER WEATHER AND WINDIER CONDITIONS THE DESERT  
FACING SLOPES INTO THE DESERTS. LATEST MODEL GUIDANCE POINTS TO  
WIDESPREAD WINDS 30-45 MPH BY FRIDAY AFTERNOON AND NIGHT, LOCALLY  
OVER 50 MPH IN THE SAN GORGONIO PASS. HIGH TEMPERATURES BY FRIDAY  
WILL BE GENERALLY 5 TO 10 DEGREES BELOW NORMAL WITH HIGHS 70-80  
FROM THE COAST INTO THE FOOTHILLS AND HIGH DESERT.  
 
MODEL GUIDANCE REMAINS IN GOOD AGREEMENT OF THE TROUGH DEPARTING  
AND A SECONDARY WEAKER TROUGH MOVING INTO ITS PLACE OVER THE  
WEEKEND. SINCE THE GRADIENT WILL RELAX, WINDS ACROSS INLAND AREAS  
WILL BE LIGHTER. HIGH TEMPERATURES WILL REMAIN SIMILAR TO THAT OF  
FRIDAY WITH COOLER THAN NORMAL READINGS WITH HIGHS IN THE UPPER  
80S TO NEAR 90 DEGREES IN THE LOWER DESERTS. THE TROUGH OVER THE  
AREA WILL SLOWLY WEAKEN, WHICH WILL LEAD TO SUBTLE WARMING ACROSS  
THE REGION INTO THE MIDDLE NEXT WEEK WITH HIGHS CLOSER TO NORMAL.  
 
 
   
AVIATION  
 
012015Z....COAST...MOSTLY CLEAR SKIES AND VFR. AREAS OF LOW CLOUDS  
BASED AROUND 1000-1500 FEET MSL TO GRADUALLY DEVELOP AFTER 02Z THIS  
EVENING. WHILE INITIALLY PATCHY, THERE IS GOOD CONFIDENCE FOR  
INCREASING COVERAGE THROUGHOUT THE NIGHT, MAINLY AFTER 10Z, ACROSS  
THE COASTAL BASIN. LOW CONFIDENCE (20-30% CHANCE) FOR PATCHY VIS  
REDUCTIONS IN VALLEYS NEAR I-15 AND I-215 DUE TO BR/HZ/FG, LIKELY  
TIMING 11-15Z. SCATTER OUT EVERYWHERE BETWEEN 15-17Z THU.  
 
VALLEYS/MOUNTAINS/DESERTS...MOSTLY CLEAR AND VFR CONDITIONS THROUGH  
THURSDAY MORNING.  
 
 
   
MARINE  
 
NORTHWEST WINDS FRIDAY AFTERNOON OVER OUTER WATERS NEAR SAN CLEMENTE  
ISLAND WILL BE SUSTAINED NEAR 20 KTS. STRONG WINDS WILL CAUSE FOR  
DANGEROUS CONDITIONS FOR SMALL CRAFT. NO OTHER 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...APR  
AVIATION/MARINE...WESTERINK  
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