162  
FXUS66 KSGX 050414  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
914 PM PDT FRI JUL 4 2025  
   
SYNOPSIS
 
 
HIGH TEMPERATURES NEAR AVERAGE WITH NIGHT AND MORNING LOW CLOUDS  
CLOSER TO THE COAST CAN BE EXPECTED THROUGH MONDAY. HIGH PRESSURE  
OVER THE DESERT SOUTHWEST WILL BUILD INTO THE REGION FOR TUESDAY  
INTO LATER NEXT WEEK, BRINGING HOTTER WEATHER FOR INLAND AREAS.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
THIS EVENING...THE MARINE LAYER IS A LITTLE SHALLOWER THAN  
YESTERDAY AFTERNOON AT ABOUT 2000 FT. AT THIS HOUR, LOW CLOUDS  
ARE FORMING AND INCREASING IN COVERAGE ALONG THE SAN DIEGO COUNTY  
COAST. HIGH-RESOLUTION MODELS INDICATE THAT LOW CLOUDS AND FOG  
WILL MAKE IT INTO ORANGE COUNTY AND SPREAD 10-15 MILES INLAND BY  
SUNRISE BEFORE CLEARING TO THE COAST BY AROUND 11 AM. HIGH  
TEMPERATURES THIS AFTERNOON WERE GENERALLY NEAR OR A FEW DEGREES  
BELOW SEASONAL AVERAGES EVEN IN THE LOWER DESERTS.  
 
FROM PREVIOUS DISCUSSION...  
A CLOSED UPPER LOW CONTINUES TO MOVE INLAND OVER THE PACIFIC  
NORTHWEST. THIS PATTERN WILL STICK AROUND INTO MONDAY AS A CLOSED  
UPPER LOW FORMS NEAR THE BAY AREA BY LATE SUNDAY. THE PRESENCE OF  
THESE FEATURES WILL HELP TO KEEP TEMPERATURES NEAR AVERAGE FOR  
EARLY JULY WITH 70S AND 80S ACROSS THE MOUNTAINS AND COASTAL  
REGIONS WITH HIGHS IN THE 90S ACROSS THE HIGH DESERT AND INLAND  
EMPIRE. THE MARINE LAYER DEPTH WILL GENERALLY REMAIN UNCHANGED  
WITH LOW CLOUDS MOVING IN UP TO AROUND 15 MILES INLAND EACH NIGHT  
AND RETREATING EACH MORNING.  
 
THE LOW MENTIONED ABOVE WILL KEEP AN AREA OF HIGH PRESSURE OVER  
THE DESERT SOUTHWEST AT BAY OVER THE NEXT FEW DAYS. MODELS SUGGEST  
THIS WILL NOT LAST AS THE AREA OF HIGH PRESSURE IS EXPECTED TO  
STRENGTHEN OVER ARIZONA, MOVING CLOSER TO SOCAL BY TUESDAY. THIS  
WILL INCREASE TEMPERATURES A FEW MORE DEGREES THAN WHAT WE WILL  
HAVE SEEN OVER THE HOLIDAY WEEKEND. ENSEMBLE MODELS CONTINUE TO  
SHOW THE SYSTEM GROWING AND EXPANDING OVER MUCH OF OUR REGION BY  
WEDNESDAY THROUGH AT LEAST FRIDAY, PROMPTING THE FIRST NOTABLE  
HEAT WAVE OF THE SUMMER. LOW LEVEL MONSOONAL MOISTURE WILL BEGIN  
TO MOVE INTO THE REGION BY TUESDAY AND WEDNESDAY. THOUGH THE  
CHANCE FOR ANY STORM ACTIVITY REMAINS BELOW 10 PERCENT, INCREASING  
MOISTURE WILL LEAD TO INCREASES IN HUMIDITY THROUGHOUT THE  
REGION. THOSE WITHOUT ANY SUFFICIENT COOLING MEASURES OR HAVING TO  
WORK OUTSIDE DURING THIS TIME INTO THE END OF THE WEEK WILL NEED  
TO TAKE PRECAUTIONS TO STAY COOL.  
 
MORE NOTABLE WARMING WILL TAKE PLACE BY WEDNESDAY AND THURSDAY  
WITH HIGH TEMPERATURES INCREASING TO 5 TO 10 DEGREES ABOVE NORMAL.  
CHANCES FOR 100 DEGREE OR GREATER TEMPERATURES ARE HIGH ACROSS THE  
IE AND THE HIGH DESERT, WITH CLOSER TO 50-70% FOR SOME INLAND  
VALLEYS/FOOTHILLS ACROSS SAN DIEGO COUNTY SUCH AS RAMONA AND PINE  
VALLEY. HIGHS OVER 115 ACROSS THE LOWER DESERTS STILL REMAINS  
SOMEWHAT IN QUESTION AS HIGHER HUMIDITY CAN ACT TO SUPPRESS THE  
HOTTEST, DRY AIR THAT COMES WITH LARGE AREAS OF HIGH PRESSURE NEAR  
600 DM. IT WILL STILL BE HOT AND HUMID ACROSS THIS REGION, BUT HOW  
MUCH SO STILL REMAINS UNCERTAIN. ENSEMBLE MODELS SHOW FAIR  
AGREEMENT IN A SUBTLE WEAKENING OF THE HIGH BY FRIDAY, WHICH MAY  
GIVE A WEAK ONSHORE PUSH OF COOLING WEST OF THE MOUNTAINS. SOME  
MODELS CONTINUE TO A DEPICT THE HIGH STICKING AROUND INTO NEXT  
WEEKEND, WHICH LEADS TO HIGHER CONFIDENCE THAT THE HEAT WILL STICK  
AROUND AS WE HEAD INTO MID JULY.  
 

 
   
AVIATION
 
 
050300Z....COAST/VALLEYS...LOW CLOUDS WITH BASES 900-1200FT MSL HAVE  
BEGUN TO REDEVELOP AND MOVE GRADUALLY ONSHORE THIS EVENING, AND WILL  
UP TO 10-15 MILES INLAND BY 11Z TONIGHT. LOW CLOUDS WILL BRING VIS  
REDUCTIONS DOWN TO 2-4SM ON COASTAL MESAS AND IN WESTERN VALLEYS.  
CLEARING OF LOW CLOUDS BACK TO THE COAST WILL OCCUR QUICKLY SATURDAY  
MORNING, BY 16-17Z. VFR PREVAILS SATURDAY AFTERNOON AND EVENING,  
BEFORE PATCHIER LOW CLOUDS BASED 600-1000 FT MSL REDEVELOP AND MOVE  
ASHORE LATE IN THE EVENING, LIKELY AFTER 06Z SUN.  
 
VIS RESTRICTIONS (2-6SM) WILL BE POSSIBLE IN FU ASSOCIATED WITH  
FIREWORKS THIS EVENING, ESPECIALLY IN ORANGE COUNTY AND WESTERN IE.  
 
MOUNTAINS/DESERTS...SUNNY WITH MOSTLY UNRESTRICTED VIS THROUGH  
SATURDAY. LOCATIONS NEAR FIREWORKS DISPLAYS MAY BRIEFLY SEE REDUCED  
VIS DUE TO FU GENERALLY BELOW 1000FT MSL.  
 

 
   
MARINE
 
 
NO HAZARDOUS MARINE WEATHER CONDITIONS ARE EXPECTED THROUGH  
WEDNESDAY.  
 

 
   
BEACHES
 
 
SOUTHERLY SWELL (190 DEGREES) OF 3 TO 4 FEET AT 15-17 SECONDS WILL  
GENERATE ELEVATED SURF OF 4-6 FT WITH SETS TO 7 FT ALONG SOUTH  
FACING BEACHES THROUGH SUNDAY. IN ADDITION, STRONG RIP AND LONGSHORE  
CURRENTS ARE EXPECTED AT ALL BEACHES THROUGH SUNDAY. A BEACH HAZARDS  
STATEMENT IS IN EFFECT AND CONTAINS MORE INFORMATION. THE PERIOD  
WILL BEGIN TO LOWER ON SUNDAY, BUT SWELL WILL REMAIN ELEVATED INTO  
MONDAY.  
 

 
   
SKYWARN
 
 
SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE  
ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS.  
 

 
   
SGX WATCHES/WARNINGS/ADVISORIES
 
 
CA...BEACH HAZARDS STATEMENT THROUGH SUNDAY EVENING FOR ORANGE COUNTY  
COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.  
 
PZ...NONE.  
 

 
 

 
 
PUBLIC...PG  
AVIATION/MARINE/BEACHES...CSP  
 
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