858  
FXUS66 KSGX 072354  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
454 PM PDT FRI AUG 7 2026  
   
SYNOPSIS
 
 
THROUGH SUNDAY MODERATE HEATRISK EXPECTED FOR THE INLAND VALLEYS AND  
MOUNTAINS WITH MAJOR HEATRISK IN THE DESERTS. THERE ARE CHANCES OF  
SHOWERS AND THUNDERSTORMS IN THE MOUNTAINS EACH AFTERNOON THROUGH  
TUESDAY. THERE ARE LOWER CHANCES TODAY AND SATURDAY WITH INCREASED  
THUNDERSTORM CHANCES EARLY NEXT WEEK. COASTAL AREAS WILL CONTINUE TO  
SEE LOW CLOUDS EACH NIGHT AND MORNING THROUGH THE FORECAST PERIOD.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
   
..UPDATED AVIATION DISCUSSION
 
 
AN ISOLATED CONVECTIVE CELL DEVELOPED AROUND 8 AM ALONG THE SAN  
DIEGO COAST STARTING IN LA JOLLA AND EVENTUALLY MOVING OFFSHORE NEAR  
ENCINITAS. A FEW LIGHTNING STRIKES OCCURRED NEAR SOLANA  
BEACH/ENCINITAS. RAINFALL TOTALS OUT OF THAT CELL RANGED FROM 0.03  
INCHES OF RAIN TO 0.36 INCHES BETWEEN LA JOLLA AND ENCINITAS. FOR  
THE REST OF THE DAY, DRY CONDITIONS ARE EXPECTED WEST OF THE  
MOUNTAINS BUT THERE REMAINS SLIGHT CHANCES OF SHOWERS AND ISOLATED  
THUNDERSTORMS IN THE MOUNTAINS AND HIGH DESERT. LATEST HIGH  
RESOLUTION GUIDANCE IS INDICATING SHOWERS THAT DEVELOP TODAY AND  
SATURDAY WILL SEE RAINFALL RATES 0.10 INCH PER HOUR OR LESS, WITH  
ONLY A 10 PERCENT CHANCE OF RAINFALL RATES EXCEEDING THAT.  
 
THROUGH SUNDAY HIGH TEMPERATURES ARE EXPECTED TO RUN 5 TO 10 DEGREES  
ABOVE AVERAGE FOR INLAND AREAS. LOW TEMPERATURES WILL ALSO RUN ABOVE  
AVERAGE, MOST NOTICEABLE IN THE MOUNTAINS AND DESERTS WHERE LOWS  
WILL BE 10 TO 15 DEGREES ABOVE AVERAGE. FOR THE INLAND VALLEYS AND  
MOUNTAINS MODERATE HEATRISK IS EXPECTED WHICH MEANS THAT FOLKS WHO  
ARE SENSITIVE TO HEAT, ESPECIALLY THOSE WITHOUT CONSISTENT  
COOLING/HYDRATION WILL BE MOST IMPACTED. IN THE DESERTS, MAJOR  
HEATRISK INDICATES ANYONE MAY SEE NEGATIVE IMPACTS FROM THE HEAT IF  
PRECAUTIONS AREN'T TAKEN. MAKE SURE TO STAY HYDRATED AND IF POSSIBLE  
AVOID STRENUOUS ACTIVITY DURING THE HOTTEST PARTS OF THE DAY (10 AM  
TO 4 PM). HIGH TEMPERATURES ARE EXPECTED TO GRADUALLY DECREASE NEXT  
WEEK, BRINGING TEMPERATURES BACK DOWN TO NEAR OR SLIGHTLY BELOW  
AVERAGE BY THE MIDDLE OF NEXT WEEK.  
 
SUNDAY THROUGH TUESDAY, THE RIDGE OF HIGH PRESSURE WILL SHIFT EAST  
MORE OVER THE FOUR CORNERS REGION. THIS WILL ALLOW FOR ADDITIONAL  
INFLUXES OF MOISTURE INTO THE AREA AND INCREASE OUR CHANCES FOR  
SHOWERS AND THUNDERSTORMS. LATEST GUIDANCE DOESN'T SHOW A FORCING  
MECHANISM OUTSIDE OF THE USUAL DAYTIME HEATING FROM THE SUN BUT THAT  
COULD CHANGE AS WE GET CLOSER. THE CURRENT FORECAST KEEPS  
THUNDERSTORM CHANCES CONFINED TO THE MOUNTAINS, LOCALLY INTO THE  
HIGH DESERT, IN THE AFTERNOONS EACH DAY SUNDAY THROUGH TUESDAY. FOR  
SUNDAY, THE LATEST REFS 90TH PERCENTILE HOURLY RAINFALL RATE PEAKS  
AT 0.55 INCHES PER HOUR, WITH ONLY 10 PERCENT CHANCE OF EXCEEDING  
THAT.  
 

 
   
AVIATION
 
 
072330Z....COAST...PATCHY LOW CLOUDS TO GRADUALLY DEVELOP OVERNIGHT,  
WITH CIGS MOST LIKELY BETWEEN 10-16Z. BASES WILL BE AROUND 1000 FEET  
MSL. SCATTER OUT OF ANY CIGS BY 16Z SATURDAY. LOW CLOUDS SATURDAY  
EVENING TO DEVELOP AFTER 05Z.  
   
VALLEYS/MOUNTAINS/DESERTS
 
ISOLD TSRA IN HIGH DESERT THROUGH  
02Z. MOSTLY CLEAR THEREAFTER ACROSS THE REGION THROUGH SATURDAY,  
EXCEPT FOR SCT CUMULUS AT 10000 FEET MSL OVER MOUNTAINS AFTER 20Z  
WITH AN ISOLATED TSRA AROUND KL35.  
 

 
   
MARINE
 
 
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...HEAT ADVISORY UNTIL 8 PM PDT SUNDAY FOR RIVERSIDE COUNTY  
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO  
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO  
COUNTY MOUNTAINS.  
 
HEAT ADVISORY FROM 10 AM SATURDAY TO 8 PM PDT SUNDAY FOR ORANGE  
COUNTY INLAND AREAS-SAN DIEGO COUNTY VALLEYS-SANTA ANA  
MOUNTAINS AND FOOTHILLS.  
 
EXTREME HEAT WARNING UNTIL 8 PM PDT SUNDAY FOR APPLE AND LUCERNE  
VALLEYS-COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-SAN  
GORGONIO PASS NEAR BANNING.  
 
PZ...NONE.  
 

 
 

 
 
PUBLIC...CO  
AVIATION/MARINE...MM  
 
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