Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 080403
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
900 PM PDT TUE JUL 7 2015

.SYNOPSIS...
AN UNSEASONABLY DEEP TROUGH OF LOW PRESSURE OFF OF THE CENTRAL
CALIFORNIA COAST WILL MOVE INLAND THROUGH THURSDAY. THE TROUGH WILL
BRING COOLER WEATHER AND AN UNUSUALLY DEEP MARINE LAYER FOR EARLY
JULY...DEEP ENOUGH FOR POCKETS OF LIGHT RAIN AND DRIZZLE WEST OF THE
MOUNTAINS THE NEXT TWO NIGHTS. IT WILL BE WINDY IN THE MOUNTAINS AND
DESERTS EACH AFTERNOON. THE TROUGH WILL MOVE EAST OF THE AREA THIS
WEEKEND WITH WARMER WEATHER AND THE RETURN OF WEAK MONSOONAL FLOW
EARLY NEXT WEEK.

&&

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

AN ANOMALOUSLY DEEP 572DM UPPER LOW 400 MILES WEST OF SFO THIS
EVENING WILL BRING UNSEASONABLY COOL WEATHER TO SO-CAL THE NEXT TWO
DAYS. TEMPERATURES WILL BE 5-15 DEGREES BELOW AVERAGE ON WEDNESDAY
AND FROM 10-20 BELOW AVERAGE THURSDAY WHEN 500 MB HEIGHT ANOMALIES
REACH 3-4 STANDARD DEVIATIONS BELOW NORMAL. RECORD LOW MAXIMUM
TEMPERATURES WILL LIKELY BE BROKEN AT SEVERAL VALLEY...MOUNTAIN AND
DESERT LOCALES.

THE MARINE LAYER WILL REMAIN UNUSUALLY DEEP FOR JULY...APPROACHING
4000 FEET THURSDAY. AREAS OF LIGHT RAIN AND DRIZZLE ARE AGAIN LIKELY
WEST OF THE MOUNTAINS EACH NIGHT AND MORNING THROUGH FRIDAY. A
SHORTWAVE ROUNDING THE BASE OF THE TROUGH ON THURSDAY MAY VERY WILL
ENHANCE THE PRECIP POTENTIAL ACROSS SOUTHERN CALIFORNIA THURSDAY.
CLEARING ON WEDNESDAY WILL BE SLOW AND SOMEWHAT LIMITED AT THE
BEACHES. ON THURSDAY THERE WILL BE COOLING ALOFT BEHIND THE
SHORTWAVE WITH A 3C TEMPERATURE DECREASE AT THE INVERSION HEIGHT.
THIS COULD PROMOTE BETTER MIXING IF NOT FOR THE UNUSUALLY DEEP
MARINE LAYER THAT WILL BE IN PLACE.

IT WILL BE WINDY IN THE MOUNTAINS AND DESERTS EACH AFTERNOON AND
EVENING THROUGH FRIDAY WITH DOUBLE DIGIT ONSHORE PRESSURE GRADIENTS
TO THE DESERTS AND 20-25KT 850 MB WINDS. WIND GUSTS IN THE MTNS AND
DESERTS WILL REACH 30 TO 40 MPH IN THE WIND PRONE AREAS LIKE THE SAN
GORGONIO PASS AND ON THE DESERT SLOPES WITH A FEW GUSTS ABOVE 50
MPH.

SATURDAY THROUGH MONDAY...THE UPPER TROUGH SLOWLY DRIFTS EAST OF THE
AREA THROUGH THE PERIOD WITH INCREASING HEIGHTS...GRADUAL WARMING
AND A SHALLOWER MARINE LAYER. HIGH PRESSURE BUILDING IN FROM THE
SOUTHEAST WILL BRING WEAK MONSOONAL FLOW BACK INTO THE SOUTHWEST
EARLY NEXT WEEK.

&&

.AVIATION... 080400Z...COAST/VALLEYS...BKN/OVC STRATUS WILL AGAIN
SPREAD THROUGH THE VALLEYS AND TO THE LOWER COASTAL SLOPES BY 08Z
WITH BASES MOSTLY 1300-2000 FT MSL WITH TOPS TO 3000-3500 FT MSL.
HIGHER TERRAIN WILL BE OBSCURED. AREAS OF VIS 3-5 MI IN MIST/DRIZZLE
WILL OCCUR MAINLY 12Z-18Z WED. CLEARING WILL BE SLOW WED...GENERALLY
16-19Z IN THE VALLEYS AND 19-22Z IN COASTAL AREAS WITH SOME AREAS
NEAR THE COAST REMAINING BKN/OVC THROUGH THE AFTERNOON. KSAN/KCRQ
WILL LIKELY ONLY BE SCT FOR A SHORT TIME. STRATUS WILL SPREAD INLAND
AGAIN EARLY WED EVENING WITH SLIGHTLY HIGHER BASES AND TOPS.

MTNS/DESERTS...MOSTLY CLEAR WITH UNRESTRICTED VIS WILL PREVAIL
THROUGH WED NIGHT. AREAS OF SURFACE WINDS FROM THE WEST 15-25 KT
GUSTS 35 KT WILL OCCUR THROUGH AND EAST OF SAN GORGONIO PASS AND THE
DESERT MOUNTAIN SLOPES THROUGH 12Z WED...THEN AGAIN AFTER 22Z WED
THROUGH WED NIGHT.

&&

.MARINE... 900 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH
SUNDAY.

&&

.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...MOEDE
AVIATION/MARINE...MAXWELL


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