Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 250436
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PDT THU JUL 24 2014

.SYNOPSIS...
STRONG HIGH PRESSURE BUILDING OVER THE SOUTHWEST WILL BRING VERY
WARM AND INCREASINGLY MORE HUMID WEATHER THROUGH THE WEEKEND. A
SHALLOW MARINE LAYER WILL MODERATE TEMPERATURES IN THE COASTAL
ZONES. INCREASING MONSOONAL MOISTURE MAY PRODUCE A FEW AFTERNOON
SHOWERS OR THUNDERSTORMS OVER THE MOUNTAINS EACH AFTERNOON THROUGH
SUNDAY. CONTINUED VERY WARM EARLY NEXT WEEK WITH STRONG HIGH
PRESSURE ALOFT OVER THE SOUTHWEST.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

STRONG HIGH PRESSURE ALOFT BROUGHT ANOTHER HOT DAY TODAY WITH RECORD
HIGHS AT CAMPO (107) AND IDYLLWILD (96). HIGH TEMPERATURES REACHED
115 IN THE LOWER DESERTS BUT FELL SHY OF BREAKING ANY RECORDS.

TEMPERATURES WILL NOT BE QUITE AS HIGH ON FRIDAY...BUT IT WILL FEEL
A LITTLE MORE HUMID AS MOISTURE BEGINS TO INCREASE FROM THE SOUTH. A
HEAT ADVISORY IS IN EFFECT FOR THE INLAND EMPIRE...AND THE MOUNTAINS
AND LOWER DESERTS FRIDAY. THE COASTAL ZONES WILL BE SPARED FROM THE
HEAT BY A MARINE LAYER THAT WILL GROW A LITTLE DEEPER TONIGHT AS A
WEAK CATALINA EDDY SPINS UP OVER THE COASTAL WATERS. THE EDDY
CONTINUES THROUGH SATURDAY MORNING WHEN LOW CLOUDS MAY SPREAD A
LITTLE FARTHER INLAND. COOL OCEAN WATER AND ONSHORE FLOW SHOULD HOLD
DAYTIME TEMPERATURES TO JUST A FEW DEGREES ABOVE AVERAGE NEAR THE
COAST.

SMALL CUMULUS FORMED OVER THE MOUNTAINS TODAY. THEY WILL HAVE BETTER
GROWTH FRIDAY AS MOISTURE BEGINS TO INCREASE. THIS MOISTURE SURGE IS
APPARENT ON THE INFRARED SATELLITE LOOP THIS EVENING WITH MIDLEVEL
CLOUDS MOVING IN FROM MEXICO. PERSISTENT SSE FLOW THROUGH SUNDAY
WILL CONTINUE TO ADVECT THIS MIDLEVEL MOISTURE INTO SOUTHERN
CALIFORNIA. MODEL FORECAST SOUNDINGS KEEP THE BULK OF THIS MOISTURE
ABOVE 10KFT...AND THAT WILL KEEP THE CHANCES FOR HEAVY RAINS TO A
MINIMUM. ADDITIONALLY...THE INSTABILITY IS NOT OVERLY IMPRESSIVE
FRIDAY AND SATURDAY...BUT DAYTIME HEATING COUPLED WITH ANY WEAK
UPPER LEVEL SHORTWAVE COULD TRIGGER A FEW AFTERNOON AND EVENING
SHOWERS AND THUNDERSTORMS. THE BEST CHANCES FOR THE MOST WIDESPREAD
CONVECTION AND THE HEAVIEST RAINS WILL BE SUNDAY WHEN A STRONGER
UPPER LEVEL SHORTWAVE MOVES ACROSS SO-CAL. PWATS PEAK BTWN 1.5-1.6
INCHES DURING THIS TIME.

OUTLOOK FOR NEXT WEEK...THE SUBTROPICAL HIGH BUILDS BACK TOWARD THE
SOUTHWEST ON MONDAY IN THE WAKE OF THE DEPARTING SHORTWAVE. A BROAD
AREA OF NVA AND SYNOPTIC SCALE SUBSIDENCE BEHIND THIS WAVE COUPLED
WITH MIDLEVEL DRYING WILL CURTAIL OUR CHANCES FOR AFTERNOON
CONVECTION MONDAY AND TUESDAY. THE LONG RANGE PROGS SHOW A SMALL
RESURGENCE IN MOISTURE FOR THE MIDDLE AND LATTER STAGES OF NEXT
WEEK...BUT UNCERTAINTY IS TOO GREAT TO MENTION PRECIP CHANCES IN THE
LONG RANGE FORECAST.

&&

.AVIATION...
250300Z...COAST/VALLEYS...STRATUS WITH BASES 800-1000 FT MSL AND
TOPS TO 1200 FT MSL WILL PUSH 5-10 MILES INLAND TONIGHT BETWEEN
25/0900Z-1200Z...WITH GREATEST COVERAGE IN SAN DIEGO COUNTY. LOCAL
VIS BELOW 3 MI WILL OCCUR IN THE COASTAL VALLEYS...WHERE THE CLOUDS
INTERSECT TERRAIN. KSAN/KCRQ/KSNA WILL HAVE CIGS...THOUGH CONFIDENCE
ON TIMING IS LOW TO MODERATE. THE CLOUDS WILL ERODE TO THE COAST
BETWEEN 25/1300Z-1600Z. SCT HIGH CLOUDS AOA 15000 FT MSL WILL PASS
OVER THE AREA THROUGH THE DAY. LOW CLOUDS WITH SIMILAR BASES AND
TOPS WILL PUSH INLAND AGAIN DURING FRIDAY NIGHT AFT 26/0700Z.

MTNS/DESERTS...UNRESTRICTED VIS WILL CONTINUE THROUGH FRI NIGHT.
MOSTLY SCT CLOUDS WILL OCCUR ABOVE 15000 FT MSL THROUGH FRI...WITH
SOME CU/TCU WITH BASES 9000 FT MSL FRI MIDDAY/AFTERNOON WITH A
SLIGHT CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS.

&&

.MARINE...
AT 8 PM PDT...NO HAZARDOUS MARINE WEATHER THROUGH TUESDAY.

&&

.SKYWARN...
SPOTTER ACTIVATION MAY BE ACTIVATED THIS WEEKEND FOR ISOLATED TO
SCATTERED THUNDERSTORMS OVER THE MOUNTAINS.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...HEAT ADVISORY THROUGH 9 PM PDT FRIDAY FOR THE 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.

PZ...NONE


&&

$$

PUBLIC...MOEDE
AVIATION/MARINE...JT










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