142  
FXUS66 KSGX 250416  
AFDSGX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
910 PM PDT SAT JUN 24 2017  
   
SYNOPSIS
 
 
HOT WEATHER WILL CONTINUE IN THE INLAND EMPIRE, MOUNTAINS AND  
DESERTS SUNDAY WITH HIGH PRESSURE ALOFT. THE MARINE LAYER WILL KEEP  
COASTAL AND WESTERN VALLEY AREAS COOLER. COOLER NEXT TUESDAY THROUGH  
FRIDAY AS A PAIR OF LOW PRESSURE SYSTEMS MOVE PAST TO THE NORTH AND  
BREAK DOWN THE RIDGE.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
THERE WAS JUST ENOUGH MOISTURE AND INSTABILITY ASSOCIATED WITH A  
PASSING SHORTWAVE FOR ISOLATED THUNDERSTORMS TO FORM OVER THE SAN  
BERNARDINO MOUNTAINS THIS AFTERNOON. MOST OF THE LIGHTNING WAS CLOUD-  
TO-CLOUD, BUT THERE WERE A FEW CLOUD-TO-GROUND STRIKES. MEASURABLE  
RAIN WAS REPORTED AT BALDWIN LAKE (0.04") NEAR BIG BEAR, AND AT  
PINON HILLS (0.12") NORTH OF WRIGHTWOOD. THE THUNDERSTORM THREAT  
LOOKS TO BE A ONE-AND-DONE WITH DRIER, MORE STABLE AIR MOVING IN  
TONIGHT AND SUNDAY, ALTHOUGH THERE WILL PROBABLY BE SOME SMALLER  
CUMULUS BUILDUPS OVER THE MOUNTAINS TOMORROW AFTERNOON.  
 
HEAT IS STILL IN THE HEADLINES TODAY. PALM SPRINGS SET A RECORD HIGH  
OF 122. ELSEWHERE, RECORD HIGH MAXES AND RECORD HIGH MINIMUMS WERE  
SET AT BIG BEAR (87/60) AND IDYLLWILD (94/66). CONTINUED HOT SUNDAY  
IN THE I.E., THE MOUNTAINS AND THE DESERTS, EVEN WITH 850 MB AND 2-  
METER TEMPS DECREASING SLIGHTLY. THAT MINOR COOLING WILL BE OFFSET  
BY A DRIER AIRMASS FOR MORE EFFICIENT HEATING. IN FACT, HIGH  
TEMPERATURES IN THE INLAND EMPIRE WILL BE HIGHER TOMORROW THAN  
THEY WERE TODAY, WITH TRIPLE DIGIT HIGHS IN MOST AREAS.  
 
TUESDAY-FRIDAY: THE STALWART RIDGE OVER THE SOUTHWEST FINALLY GETS  
FLATTENED BY A SERIES OF PACIFIC SHORTWAVES PASSING THROUGH THE  
INTERMOUNTAIN WEST. FALLING HEIGHTS AND INCREASING ONSHORE FLOW WILL  
FINALLY BRING AN END TO THE OPPRESSIVE HEAT IN THE DESERTS. MAX  
TEMPS WILL BE 10 TO 15 DEGREES LOWER, AND CLOSER TO WHERE THEY  
SHOULD BE FOR LATE JUNE (THE AVERAGE HIGH AT PSP IS 105).  
 
NEXT WEEKEND THE GFS PROJECTS SOME HEIGHT/THICKNESS RECOVERY OVER  
THE SW, WHILE THE ECMWF FORECASTS CONTINUED TROUGHING WITH LOWER  
HEIGHTS AND COOLER WEATHER. EITHER WAY, THE MAX TEMPS WON'T BE  
ANYWHERE NEAR WHERE THEY WERE OVER THE LAST WEEK.  
 

 
   
AVIATION
 
 
240400Z...COAST/VALLEYS...STRATUS RE-DEVELOPING AND MOVING INLAND  
ABOUT 10 SM THROUGH 15Z SUNDAY MORNING, WITH BASES AROUND 200-700 FT  
MSL, TOPS AROUND 1200-1700 FT MSL, AREAS OF VIS 2-4 SM, AND PATCHY  
DENSE FOG POSSIBLE WITH VIS AS LOW AS 1/2 SM ALONG HIGHER COASTAL  
TERRAIN/INLAND MESAS. CIGS GRADUALLY DISSIPATING SUNDAY MORNING 15-  
18Z TO THE COAST. CONFIDENCE IN CIG HEIGHTS/VIS IS MODERATE.  
 
MOUNTAINS/DESERTS...FEW-SCT AOA 15000 FT MSL AND P6SM VIS CONTINUING  
THROUGH SUNDAY AFTERNOON.  
 

 
   
MARINE
 
 
NORTHWEST WIND GUSTS OVER THE OUTER WATERS MAY REACH 20-25 KT DURING  
THE AFTERNOONS AND EVENINGS SUNDAY THROUGH TUESDAY, POTENTIALLY  
RESULTING IN CONDITIONS HAZARDOUS TO SMALL CRAFT.  
 

 
   
BEACHES
 
 
HIGH TIDES WILL REACH 7+ FT AGAIN THIS EVENING. TIDES THIS HIGH MAY  
RESULT IN MINOR TIDAL OVERFLOW AT LOW LYING BEACHES. THE BEACH  
HAZARDS STATEMENT CONTINUES THROUGH 11 PM THIS EVENING. HIGH TIDE  
WILL FALL BELOW 7 FEET SUNDAY, LOWERING THE TIDAL OVERFLOW THREAT.  
 

 
   
FIRE WEATHER
 
 
HEAT AND GUSTY WINDS ALONG THE RIDGES, DESERT SLOPES AND PASSES WILL  
CREATE A HEIGHTENED RISK OF WILD FIRE SPREAD SUNDAY. DRIER AIR ALOFT  
WILL PRECLUDE ANY THREAT OF CONVECTION OVER THE MTS ON SUNDAY.  
 

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

 
   
SGX WATCHES/WARNINGS/ADVISORIES
 
 
CA...EXCESSIVE HEAT WARNING UNTIL 9 PM PDT MONDAY FOR COACHELLA  
VALLEY-SAN DIEGO COUNTY DESERTS-SAN GORGONIO PASS NEAR  
BANNING.  
 
HEAT ADVISORY FROM 10 AM TO 9 PM PDT SUNDAY FOR RIVERSIDE COUNTY  
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO  
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO  
COUNTY MOUNTAINS-SANTA ANA MOUNTAINS AND FOOTHILLS.  
 
EXCESSIVE HEAT WARNING UNTIL 9 PM PDT SUNDAY FOR APPLE AND  
LUCERNE VALLEYS.  
 
PZ...NONE.  
 

 
 

 
 
PUBLIC/FIRE WEATHER...MOEDE  
AVIATION/MARINE/BEACHES...BROTHERTON  
 
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