Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 060347
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
845 PM PDT TUE MAY 5 2015

.SYNOPSIS...
A COLD LOW PRESSURE TROUGH OVER THE PACIFIC NORTHWEST WILL
BRING COOL WEATHER...A DEEP MARINE LAYER AND GUSTY MOUNTAIN AND
DESERT WINDS THIS WEEK. DRIZZLE IS POSSIBLE LATE TONIGHT AND EARLY
WEDNESDAY WEST OF THE MOUNTAINS. SHOWERS ARE MOST LIKELY THURSDAY
AND FRIDAY WHEN THE TROUGH MOVES ACROSS SOUTHERN CALIFORNIA.
DRY WEATHER WILL RETURN SATURDAY FOLLOWED BY WARMER WEATHER SUNDAY
AND MONDAY UNDER WEAK HIGH PRESSURE ALOFT.

&&

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

A COLD UPPER LOW OVER THE PACIFIC NORTHWEST WILL BRING A
PERIOD OF COOL...UNSETTLED WEATHER TO SO-CAL THROUGH FRIDAY.
WEDNESDAY WILL BE ANOTHER COOL DAY WITH A DEEP MARINE LAYER IN
PLACE...PERHAPS DEEP ENOUGH FOR DRIZZLE WEST OF THE MOUNTAINS
IN THE MORNING. IT WILL BE ANOTHER WINDY DAY IN THE MOUNTAINS AND
DESERTS WEDNESDAY...BUT THE STRONGEST WINDS WILL NOT SURFACE
UNTIL THURSDAY AND THURSDAY NIGHT WHEN A 90KT 300 MB JET STREAM
TRACKS ACROSS SOUTHERN CALIFORNIA. A WIND ADVISORY IS IN EFFECT FOR
THE DESERTS DURING THIS TIME.

TEMPERATURES WILL BE SEVERAL DEGREES BELOW AVERAGE WEDNESDAY THROUGH
FRIDAY. THERE IS ALSO A PRETTY GOOD CHANCE FOR SHOWERS WITH
THIS SYSTEM THURSDAY AND FRIDAY AS THE AIRMASS DESTABILIZES BENEATH
THE COLD UPPER LOW WHERE 500 MB TEMPS FALL TO BETWEEN -20 AND -25C.
BOUNDARY LAYER MOISTURE IN THE LOWEST 8000 FEET WILL BE NEAR
SATURATION AND PWATS INCREASE TO 0.80". THIS MOISTURE AND STRONG
INSTABILITY SHOULD SUPPORT SHOWERS AND THUNDERSTORMS THURSDAY
AFTERNOON THROUGH FRIDAY MORNING.

SNOW LEVELS WILL BE QUITE LOW FOR EARLY MAY...DOWN TO AROUND 5500
FEET. PRECIPITATION AMOUNTS WILL BE VARIABLE. SOME AREAS COULD
SEE AN OVER AN INCH OF RAIN IN THE HEAVIEST SHOWERS...BUT MOST AREAS
WILL SEE AROUND A QUARTER-INCH. THE PRECIP WILL SHIFT EAST FRIDAY
NIGHT LEAVING BEHIND A COOL BREEZY DAY SATURDAY IN NORTHWEST
FLOW ALOFT. MUCH WARMER SUNDAY AND MONDAY WITH WEAK RIDGING ALOFT.

&&

.AVIATION...
060300Z...COAST/VALLEYS... LOW CLOUDS...WITH BASES
BETWEEN 3000-3500 FT MSL AND TOPS TO 4500 FT MSL...WILL DEVELOP
ALONG THE COAST THIS EVENING...AND PUSH INLAND TO THE COASTAL MTN
SLOPES. LOW CLOUDS MAY OBSCURE TERRAIN IN THE FOOTHILLS. STRATUS
WILL BECOME SCT/FEW LATE WEDNESDAY MORNING...THEN BECOME BKN/OVC
WEDNESDAY EVENING WEST OF THE MTNS WITH SIMILAR TOPS AND BASES.

MTNS/DESERTS..WESTERLY WIND GUSTS TO 35 KT WILL PRODUCE MODERATE
UDDFS/LLWS OVER AND EAST OF THE MTNS THROUGH 15Z WEDNESDAY. ISOLATED
STRONGER GUSTS TO 50 KT ARE LIKELY THROUGH AND BELOW THE SAN
GORGONIO PASS. OTHERWISE...MOSTLY SKC THROUGH WEDNESDAY EVENING.

&&

.MARINE...
900 PM...A DISTURBANCE MOVING ACROSS THE REGION WILL
CREATE A CHANCE OF THUNDERSTORMS AND ISOLATED CLOUD-TO-WATER
LIGHTNING STRIKES OVER THE COASTAL WATERS THU NIGHT INTO FRI
MORNING. OTHERWISE...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH
SUNDAY.

&&

.BEACHES...
900 PM...SURF WILL LOWER OVERNIGHT FROM HIGH TO ELEVATED
AS THE SOUTHERLY SWELL CONTINUES TO DECREASE. ISOLATED SETS TO 8-10
FT WILL BE POSSIBLE WEDNESDAY ALONG SOUTHERLY FACING BEACHES. STRONG
RIP AND LONG SHORE CURRENTS WILL CONTINUE THROUGH THE END OF THE
WEEK AND THE SWELL DECREASES.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY FROM 4 PM WEDNESDAY TO 3 AM PDT FRIDAY FOR APPLE
     AND LUCERNE VALLEYS-SAN DIEGO COUNTY DESERTS-SAN GORGONIO
     PASS NEAR BANNING.

     HIGH SURF ADVISORY UNTIL 11 PM PDT THIS EVENING FOR ORANGE
     COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS.

PZ...NONE.
&&

$$

PUBLIC...MOEDE
AVIATION/MARINE/BEACHES...JJT


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