981  
FXUS66 KSGX 262031 CCA  
AFDSGX  
 
AREA FORECAST DISCUSSION...CORRECTED FOR BEACHES SEGMENT  
NATIONAL WEATHER SERVICE SAN DIEGO CA  
130 PM PDT SUN JUN 26 2016  
 
   
SYNOPSIS
 
 
HIGH PRESSURE ALOFT WILL BRING A WARMING TREND INTO TUESDAY...THEN  
COOLING INTO NEXT WEEKEND AS HIGH PRESSURE WEAKENS AND A WEAK TROUGH  
OF LOW PRESSURE DEVELOPS OFF THE CALIFORNIA COAST. IT WILL BE QUITE  
HOT INLAND, BUT THE MARINE LAYER WILL KEEP COASTAL AREAS MORE MILD,  
WITH PATCHY NIGHT AND MORNING LOW CLOUDS AND FOG. MOISTURE ALOFT FROM  
THE SOUTHEAST WILL BRING MORE CLOUDS FOR MONDAY, WITH A SLIGHT CHANCE  
OF AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS NEAR THE  
MOUNTAINS. THE ELEVATED SURF CONDITIONS WILL SUBSIDE TONIGHT AND  
MONDAY.  
 

 
   
DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE
 
 
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO  
COUNTIES...  
 
THE MARINE STRATUS REMAINED EXTENSIVE OFFSHORE AT MIDDAY, BUT WAS  
ONLY JUST STARTING TO DEVELOP ALONG THE THE SAN DIEGO/O.C. COUNTY  
COASTS IN RESPONSE TO THE SEA BREEZE. FARTHER TO THE EAST, CLOUDS  
WERE DEVELOPING OVER THE MOUNTAINS, MAINLY SAN DIEGO COUNTY. THIS WAS  
ALONG THE LEADING EDGE OF A LARGER CLOUD MASS SPREADING WEST ACROSS  
SW AZ AND FAR NW MEXICO. AT MIDDAY, THE SURFACE PRESSURE GRADIENT  
KSAN-LOWER DESERTS HAD INCREASED TO AROUND 4 MBS AND WINDS HAD  
PICKED UP TO 15-25 MPH OVER SOME MTN/DESERT AREAS.  
 
A HEAT ADVISORY IS IN EFFECT FOR THE INLAND EMPIRE AND ALL FAR INLAND  
MOUNTAIN AND DESERT AREAS THROUGH WEDNESDAY. WITH MORE CLOUDS  
EXPECTED ON MONDAY, IT MAY BE SLIGHTLY COOLER, THEN WARMER AGAIN  
TUE/WED.  
 
FORECAST CONFIDENCE DROPS TOMORROW DUE TO THE PASSAGE OF AN EASTERLY  
WAVE. MODELS ARE NOT PRODUCING MUCH IN THE WAY OF PRECIP WITH IT, BUT  
IT DOES BRING IN A SIGNIFICANT AMOUNT OF MOISTURE (PW 1.4 INCH). AT  
THE SAME TIME, THE MID-LEVEL WINDS INCREASE TO AROUND 30 KT. THIS  
MAKES IT TOUGH FOR CONVECTION TO FORM OVER OUR MTS UNTIL THE WINDS  
DROP OFF LATE IN THE DAY. THE AMOUNT OF CLOUD COVER WILL BE CRITICAL  
AS WELL, FOR HEATING AND POSSIBLE CONVECTION. IF NO CELLS CAPABLE OF  
THUNDER FORM, CLOUDS AND SPRINKLES MAY BE THE MOST WE SEE AS THE  
MODELS HOLD A DEEP DRY LAYER IN PLACE UNDER THE MOISTURE.  
 
IF A FEW CELLS GET GOING ON MON, EITHER BECAUSE OF ELEVATED  
INSTABILITY, OR MOUNTAIN TOP HEATING, STEERING CURRENTS WOULD DRIVE  
THEM WEST BEFORE DISSIPATING, SO A SLIGHT CHANCE FOR SHWRS/TSTMS HAS  
BEEN ADDED TO THE VALLEYS. AS THE WAVE PASSES ON TUE, MOISTURE  
DECREASES AND SUBSIDENCE MAY WELL OVERWHELM ANY MOUNTAIN TOP  
HEATING, BUT A SLIGHT CHANCE FOR SHWRS/TSTMS IS STILL IN THE  
FORECAST FOR THE AFTERNOON ALONG THE HIGHER MOUNTAINS.  
 
IN TERMS OF THE BIGGER PICTURE...A HIGH PRESSURE RIDGE OVER THE SW  
WILL BUILD NE AND PEAK OVER UTAH ON TUE AT 597 DM BEFORE DEFLATING.  
AN EASTERLY WAVE WILL RIDE THE EAST FLOW AROUND THE SOUTH SIDE OF THE  
RIDGE ON MONDAY, BRINGING AN INCREASE IN CLOUDS AND A SLIGHT CHANCE  
OF SHWRS/TSTMS OVER THE MTS AND ADJACENT VALLEYS. THIS CHANCE  
DWINDLES RAPIDLY AS THE WAVE PASSES ON TUE. FURTHER WEAKENING OF THE  
RIDGE ALOFT ALLOWS A WEAK TROUGH TO DEVELOP ALONG THE COAST FOR THE  
LATTER HALF OF THE WEEK. THIS WILL INCREASE THE ONSHORE FLOW AND HELP  
TO REBUILD THE MARINE LAYER FOR COOLER CONDITIONS. THE ECMWF RUN IS  
THE MOST AGGRESSIVE WITH THE DEVELOPING TROUGH EARLY NEXT WEEK.  
 
IN THE MEDIUM TERM, A LESS AMPLIFIED UPPER-AIR PATTERN IS FORECAST TO  
PREVAIL THROUGH THE UPCOMING HOLIDAY WEEKEND, PROVIDING SEASONAL  
WEATHER CONDITIONS ACROSS SOCAL.  
 

 
   
AVIATION
 
 
262009Z...COAST/VALLEYS...THROUGH 27/0300 UTC, OTHER THAN SOME BKN-  
SCT CLOUDS NEAR THE COAST 1100-1500 FT MSL, PRIMARILY UNRESTRICTED  
VIS WITH FEW-SCT CLOUDS AOA 10000 FT MSL EXPECTED. 27/0300-1500 UTC,  
PATCHY STRATUS GRADUALLY DEVELOPING 15-20 SM INLAND WITH BASES 600-  
1100 FT MSL, TOPS AROUND 1200-1500 FT MSL, LOCAL VIS 3-5 SM AND ALSO  
POSSIBLE VIS AOB 1 SM ALONG HIGHER COASTAL TERRAIN/MESAS. CONFIDENCE  
IS LOW-TO-MODERATE IN STRATUS OCCURRENCE AND TIMING, WITH MODERATE  
CONFIDENCE IN BASES/TOPS. OTHERWISE, UNRESTRICTED VIS CONTINUING  
WITH BKN-SCT CLOUDS AOA 10000 FT MSL.  
 
MOUNTAINS...MAINLY UNRESTRICTED VIS THROUGH MONDAY MORNING, WITH BKN-  
SCT CLOUDS AOA 10000 FT MSL.  
 
DESERTS...UNRESTRICTED VIS WILL CONTINUE THROUGH MONDAY  
MORNING WITH INCREASING CLOUDS AOA 10000 FT MSL.  
 

 
   
MARINE
 
 
109 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH FRIDAY.  
 

 
   
BEACHES
 
 
124 PM...NEARSHORE BUOY REPORTS SHOWED A LONG-PERIOD SOUTH SWELL AT  
4-5 FT/17-18 SECONDS, WHICH IS INDICATIVE OF A SLIGHT LOWERING TREND.  
HOWEVER, 5-7 FOOT SURF IS STILL BEING REPORTED IN SOME ORANGE COUNTY  
BEACHES, SO THE HIGH SURF ADVISORY REMAINS IN EFFECT. MEANWHILE,  
SURF IN SAN DIEGO COUNTY IS AT AROUND 3-6 FEET. ALTHOUGH SWELL AND  
SURF MAY GRADUALLY LOWER TODAY, STRONG LONGSHORE AND RIPS CURRENTS  
WILL CONTINUE TO CREATE HAZARDOUS SWIMMING CONDITIONS. A BEACH  
HAZARD STATEMENT REMAINS IN EFFECT FOR SAN DIEGO COUNTY FOR ABOVE  
AVERAGE SURF AND STRONG RIP CURRENTS. SURF AND SWELL WILL LOWER  
FURTHER TONIGHT THROUGH MONDAY, WITH SURF LOWERING TO 1-3 FEET BY  
TUESDAY. THIS WILL RESULT IN A LESSENING RIP CURRENT RISK AS WELL.  
HOWEVER, ANOTHER LONG-PERIOD SOUTH SWELL FROM 200 DEGREES WILL MOVE  
IN ON WEDNESDAY, RESULTING IN INCREASING SURF AND STRONG RIP  
CURRENTS ONCE AGAIN.  
 

 
   
FIRE WEATHER
 
 
CRITICAL FIRE WEATHER CONDITIONS ARE NOT EXPECTED, HOWEVER THE THREAT  
OF WILDFIRE WILL BE ELEVATED EACH DAY DUE TO THE HEAT AND DRYNESS.  
 
DAYTIME TEMPERATURES WILL BE RUNNING AROUND 5-10 DEGREES F ABOVE  
AVERAGE ACROSS THE VALLEYS/MTS/DESERTS THROUGH WEDNESDAY, ALONG WITH  
MINIMUM RH AROUND 15 PERCENT.  
 
WINDS WILL BE MOSTLY UNDER 15 MPH, EXCEPT WITH THE ONSET OF THE SEA  
BREEZE EACH AFTERNOON, AND THROUGH THE PASSES WHERE LOCAL GUSTS OF  
25-35 MPH ARE POSSIBLE LATE EACH DAY.  
 
ISOLATED DRY LIGHTNING STRIKES ARE POSSIBLE, MONDAY AND TUESDAY  
AFTERNOON/EVENING NEAR THE MOUNTAINS.  
 

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

 
   
SGX WATCHES/WARNINGS/ADVISORIES
 
 
CA...HEAT ADVISORY FROM NOON TODAY TO 8 PM PDT WEDNESDAY FOR APPLE  
AND LUCERNE VALLEYS-COACHELLA VALLEY-RIVERSIDE COUNTY  
MOUNTAINS-SAN BERNARDINO COUNTY MOUNTAINS-SAN BERNARDINO  
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-SAN DIEGO  
COUNTY DESERTS-SAN DIEGO COUNTY MOUNTAINS-SAN GORGONIO PASS  
NEAR BANNING.  
 
BEACH HAZARDS STATEMENT THROUGH THIS EVENING FOR SAN DIEGO  
COUNTY COASTAL AREAS.  
 
HIGH SURF ADVISORY UNTIL 8 PM PDT THIS EVENING FOR ORANGE COUNTY  
COASTAL AREAS.  
 
PZ...NONE.  
 

 
 

 
 
PUBLIC/FIRE WEATHER...JAD  
AVIATION/MARINE/BEACHES...HARRISON  
 
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