409  
FXUS66 KSGX 190435 AAA  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
930 PM PDT THU AUG 18 2022  
   
SYNOPSIS
 
 
THE SUMMER DOLDRUMS WILL CONTINUE THROUGH NEXT WEEK WITH WARM AND  
HUMID WEATHER. A WEAK MONSOONAL FLOW WILL MAINTAIN A CHANCE FOR  
MAINLY AFTERNOON AND EVENING THUNDERSTORMS OVER THE MOUNTAINS AND  
DESERTS. THE GREATEST CHANCES FOR THUNDERSTORMS WILL BE FRIDAY AND  
SATURDAY, AND AGAIN AROUND THE MIDDLE OF NEXT WEEK. PATCHY NIGHT AND  
MORNING LOW CLOUDS AND FOG WILL SPREAD INLAND EACH NIGHT, AND THEN  
BURN BACK OFFSHORE EACH MORNING, ALONG WITH PERIODS OF HIGHER CLOUDS  
AT TIMES.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
EVENING UPDATE:  
 
NO UPDATED WERE NEEDED THIS EVENING. VERY LIMITED CONVECTION  
OCCURRED TODAY WITHIN OUR AREA, THERE WERE JUST A COUPLE OF CELLS IN  
THE SANTA ROSA MOUNTAINS, JUST WEST OF THE COACHELLA VALLEY.  
CONVECTION WAS PROBABLY LIMITED DUE TO SUBSIDENCE ALONG THE EASTERN  
PERIPHERY OF THE EAST PAC HIGH PRESSURE RIDGE. THERE MAY BE A LITTLE  
BETTER CHANCE FOR CONVECTION FRIDAY AFTERNOON, BUT STILL ONLY  
ISOLATED COVERAGE IS EXPECTED FOR FRIDAY AFTERNOON AND EARLY  
EVENING. NONETHELESS CONDITIONS WILL REMAIN VERY WARM AND HUMID  
ACROSS SOCAL, AND ANY STORMS THAT DEVELOP COULD CONTAIN BRIEF HEAVY  
DOWNPOURS AND SLOW STORM MOTION.  
 
REMAINDER OF PREVIOUS DISCUSSION (ISSUED AT 148 PM PDT):  
 
HIGH PRESSURE ALOFT WILL REMAIN IN CONTROL OVER THE SW THROUGH THE  
WEEKEND AND NEXT WEEK. SHIFTING AND REPOSITIONING OF THE AXIS OF  
HIGH PRESSURE WILL DETERMINE THE DIRECTION OF OUR WEAK FLOW ALOFT,  
AND ULTIMATELY, MOISTURE AVAILABILITY. THROUGH THE COMING WEEKEND,  
WE WILL REMAIN ON THE EDGE OF SOME VERY DEEP TROPICAL MOISTURE THAT  
IS SMOTHERING NW MX AND THE LOWER COLORADO RIVER VALLEY OF SE CA.  
ANY CONVECTIVE SYSTEMS THAT DEVELOP THERE, COULD INFLUENCE OUR  
WEATHER, DUE TO OUTFLOW AND CONVECTIVE DEBRIS. FORECASTING THOSE  
DETAILS BEYOND ANYTHING MORE THAN 12-24 HOURS WILL BE DIFFICULT TO  
IMPOSSIBLE, SO EXPECT FORECAST ADJUSTMENTS.  
 
BASED ON THE VARIOUS ENSEMBLE PROJECTIONS, MORE SHOW GREATER  
PRECIPITABLE WATER VALUES AT VARIOUS PLACES IN THE CWA FRIDAY INTO  
SATURDAY, WITH DRIER SOLUTIONS PREDOMINATING EARLY NEXT WEEK,  
FOLLOWED BY ANOTHER INCREASE IN MOISTURE MID NEXT WEEK. FOLLOWING  
THE PW TRENDS GIVES US SOME VARIATION IN THE POPS, BUT NOTHING  
CONCRETE. BOTTOM LINE...WE REMAIN IN A WEAK MONSOON PATTERN WELL  
INTO NEXT WEEK, WHICH FAVORS AFTERNOON, MOUNTAIN CONVECTION, AND TO  
A LESSER EXTENT, THE DESERTS. AS OF NOW, WE DON'T SEE A GOOD CHANCE  
FOR ANY OF THIS ACTIVITY TO MAKE IT TO THE COAST, BUT IT WOULDN'T BE  
SURPRISING IF SOMETHING DIDN'T DEVELOP NEXT WEEK FOR A FEW HOURS.  
 
EXCEPT FOR PERIODS OF EXTENSIVE CLOUDINESS FROM THE EAST, AND/OR  
PRECIPITATION, DAYTIME TEMPERATURES WILL BE CLOSE TO MID SUMMER  
AVERAGES.  
 

 
   
AVIATION
 
 
190400Z...COAST/VALLEYS...AREAS OF LOW CLOUDS WILL CONTINUE  
DEVELOPING ALONG THE IMMEDIATE COAST THROUGH 08Z FRI AND SPREAD UP  
TO 20 MILES INLAND BY 13Z FRI. BASES WILL BE 1000-1200 FT MSL WITH  
TOPS TO 1400 FT MSL. LOCAL VIS 3-5 MILES WILL OCCUR IN THE COASTAL  
VALLEYS 10Z-15Z. MOST AREAS WILL CLEAR 15Z-17Z WITH MOSTLY SCT  
CLOUDS AT/ABOVE 15000 FT MSL FRI AFTERNOON. AREAS OF STRATUS WILL  
DEVELOP NEAR THE IMMEDIATE COAST AGAIN FRI EVENING.  
 
MOUNTAINS/DESERTS...SCT-OCCASIONAL BKN CLOUDS AT/ABOVE 15000 FT MSL  
WILL CONTINUE THROUGH FRI EVENING WITH MOSTLY UNRESTRICTED VIS.  
THERE IS A SLIGHT CHANCE OF TSRA FRI AFTERNOON/EARLY EVENING WITH  
BASES 8000-10000 FT MSL AND TOPS TO 40000 FT MSL ALONG WITH STRONG  
UP/DOWNDRAFTS AND LOCAL GUSTY SURFACE WINDS.  
 

 
   
MARINE
 
 
NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH TUESDAY.  
 

 
   
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...10/JMB  
AVIATION/MARINE...MAXWELL  
 
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