481  
FXUS66 KSGX 021550  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
850 AM PDT THU JUL 2 2020  
   
SYNOPSIS
 
 
HIGH PRESSURE TO THE SOUTHEAST WILL BRING A WARMING TREND INTO  
SUNDAY WITH SUNDAY HIGH TEMPERATURES AROUND 5 TO 8 DEGREES ABOVE  
AVERAGE. THIS WILL BE FOLLOWED BY A SLOW COOLING TREND FOR MONDAY  
THROUGH WEDNESDAY WITH WEDNESDAY HIGH TEMPERATURES A FEW TO  
AROUND 5 DEGREES BELOW AVERAGE. THE MARINE LAYER WILL BECOME  
SHALLOWER WITH NIGHT AND MORNING COASTAL LOW CLOUDS AND FOG NOT  
SPREADING MUCH FARTHER INLAND THAN COASTAL AREAS FOR SUNDAY AND  
MONDAY MORNINGS. THE LOW CLOUDS WILL SPREAD BACK INTO PORTIONS OF  
THE VALLEYS BY THE MIDDLE OF NEXT WEEK.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
THIS MORNING LOOKS AN AWFULLY LOT LIKE YESTERDAY MORNING WITH A  
DEEP MARINE LAYER IN PLACE AND LOW CLOUDS BLANKETING THE COASTAL  
BASIN. CLOUDS HAVE EVEN SNUCK THROUGH THE CAJON PASS AND ARE  
NEARLY SPILLING INTO THE HIGH DESERT. VISIBLE SATELLITE SHOWS  
CLOUDS HAVE BEGUN TO CLEAR ALONG THE FOOTHILLS. THE MARINE LAYER  
DEPTH IS VIRTUALLY UNCHANGED FROM YESTERDAY AND THE INVERSION JUST  
AS STRONG, SO EXPECT SLOW CLEARING ONCE AGAIN, WITH COASTAL AREAS  
REMAINING MOSTLY CLOUDY THROUGH THE DAY. ELSEWHERE REMAINS CLEAR.  
 
AN UPPER LEVEL HIGH CURRENTLY OVER NORTHERN MEXICO WILL SLOWLY  
EXPAND NORTHWEST TOWARDS SOUTHERN CALIFORNIA INTO THE WEEKEND,  
BRINGING GRADUAL WARMING AND HIGHS RETURNING TO NEAR NORMAL BY  
SATURDAY. THE MARINE LAYER WILL FINALLY BECOME MORE SHALLOW, WITH  
LESS INLAND EXTENT OF COASTAL LOW CLOUDS EACH NIGHT. THERE IS A  
CHANCE THAT THE BEACHES COULD BE MOSTLY CLOUDY THROUGH THE DAY ON  
THE FOURTH OF JULY, ESPECIALLY IN SAN DIEGO COUNTY.  
 
THE CENTER OF THE HIGH SHIFTS WEST AND OVER SO CAL FOR SUNDAY AND  
MONDAY, BRINGING GREATER WARMING WITH HIGHS 5 TO 8 DEGREES ABOVE  
NORMAL. HIGHS IN THE INLAND EMPIRE AND HIGH DESERT WILL BE IN THE  
MID TO UPPER 90S, WITH HIGHS IN EXCESS OF 110 IN THE LOW DESERTS  
THESE DAYS. THE MARINE LAYER WILL BE SHALLOW ENOUGH FOR PATCHY  
DENSE FOG OVER THE COASTAL MESAS AND HIGHER COASTAL TERRAIN ON  
SUNDAY, AND AT THE BEACHES SUNDAY NIGHT INTO MONDAY, THOUGH CLOUDS  
MAY BE FAIRLY PATCHY BY THEN.  
 
SLOW COOLING TAKES PLACE TUESDAY THROUGH THURSDAY WITH HIGHS NEAR  
SEASONAL AVERAGES. MORE EXPANSIVE AND STRONGER HIGH PRESSURE MAY  
DEVELOP LATE NEXT WEEK OVER THE CENTRAL AND SOUTHERN ROCKIES INTO  
THE SOUTHWESTERN STATES. THIS WOULD BRING A WARMING TREND LATE  
NEXT WEEK INTO NEXT WEEKEND. MONSOON MOISTURE WILL REMAIN WELL TO  
THE SOUTHEAST THROUGH FRIDAY. THE MAJORITY OF EC ENSEMBLE MEMBERS  
SHOW MOISTURE BEGINNING TO OVERSPREAD SO CAL BY SATURDAY AND  
REMAINS ELEVATED THROUGH MUCH OF THE FOLLOWING WEEK. THE 00Z GFS  
ENSEMBLE IS ON THE DRIER SIDE AND HOLDS OFF UNTIL CLOSER TO THE  
MIDDLE OF THAT WEEK, THOUGH THERE IS MUCH SPREAD IN THE SOLUTIONS.  
INTERESTINGLY, THE 06Z DETERMINISTIC GFS IS MORE IN LINE WITH THE  
EC ENSEMBLES IN TERMS OF MOISTURE. CONFIDENCE IS LACKING AT THIS  
POINT, BUT AT LEAST SOME SIGNS ARE POINTING TO THE FIRST MONSOON  
PUSH BY MID JULY.  
 

 
   
AVIATION
 
 
020900Z...COAST/VALLEYS...LOW CLOUDS WITH BASES 1500-2000 FT MSL  
WILL CONTINUE TO FILL INTO THE INLAND VALLEYS THIS MORNING. REDUCED  
VISIBILITY OF 3-5 MILES WILL OCCUR IN THE INLAND VALLEYS WHERE  
CLOUDS AND TERRAIN INTERSECT. SCATTER OUT EXPECTED IN THE VALLEYS 15-  
17Z AND ALONG THE COAST FROM 19-21Z. SOME PATCHY LOW CLOUDS COULD  
LINGER ALONG THE BEACHES THROUGH THE AFTERNOON. LOW CLOUDS WILL MOVE  
BACK IN AFTER 03Z, WITH LOWER BASES AND LESS INLAND EXTENT.  
 
MOUNTAINS/DESERTS...MOSTLY CLEAR WITH UNRESTRICTED VIS THROUGH  
TODAY.  
 

 
   
AVIATION
 
 
021530Z...COAST/VALLEYS...LOW CLOUDS WITH BASES 1500-2000 FT MSL AND  
TOPS TO 2800 FT MSL COVER MOST OF THE REGION WEST OF THE MTNS.  
REDUCED VISIBILITY OF 1-3 MILES WILL OCCUR WHERE CLOUDS AND TERRAIN  
INTERSECT. CLEARING EXPECTED INLAND 15-17Z AND ALONG THE COAST FROM  
19-21Z. SOME LOW CLOUDS WILL LIKELY LINGER ALONG THE BEACHES THROUGH  
THE AFTERNOON. LOW CLOUDS WILL AGAIN INCREASE IN COVERAGE AND SPREAD  
INLAND AFTER 03Z FRIDAY, WITH LOWER BASES AND TOPS NOT REACHING  
AS FAR INLAND.  
 
MOUNTAINS/DESERTS...MOSTLY CLEAR WITH UNRESTRICTED VIS THROUGH  
TONIGHT.  
 

 
   
MARINE
 
 
NO HAZARDOUS MARINE CONDITIONS ARE EXPECTED THROUGH WEDNESDAY.  
 

 
   
BEACHES
 
 
LONG-PERIOD SOUTHWEST SWELL WILL CONTINUE 3-6 FT SURF THROUGH TODAY,  
WITH THE HIGHEST SURF IN ORANGE COUNTY. A LARGER SOUTHWEST SWELL  
WITH A 16-18 SEC PERIOD WILL BEGIN TO BUILD IN FRIDAY AND GENERATE  
EVEN HIGHER SURF OVER THE FOURTH OF JULY HOLIDAY WEEKEND ALONG WITH  
STRONG RIP AND LONGSHORE CURRENTS. HIGHEST SURF AGAIN WILL BE IN  
ORANGE COUNTY WHERE SOME 8 FOOT SETS WILL BE LIKELY.  
 

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

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

 
 

 
 
PUBLIC...SS  
AVIATION/MARINE/BEACHES...PG  
 
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