Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 232029
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
129 PM PDT SAT MAY 23 2015

.SYNOPSIS...LOW PRESSURE OVER THE GREAT BASIN WILL MAINTAIN GUSTY
WESTERLY WINDS IN THE MOUNTAINS AND DESERTS...AND ABUNDANT CLOUD
COVER ALONG AND WEST OF THE MOUNTAINS. AREAS OF LIGHT PRECIPITATION
WILL LIKELY REDEVELOP AGAIN OVERNIGHT INTO SUNDAY MORNING AS A FAST-
MOVING LOW PRESSURE SYSTEM DROPS SOUTH ACROSS THE STATE. LOW
PRESSURE ALOFT AND ONSHORE FLOW WILL GRADUALLY WEAKEN THROUGH THE
UPCOMING WEEK...ALLOWING SLOW INLAND WARMING AS THE MARINE LAYER
BECOMES MORE SHALLOW.

&&

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

MARINE CLOUDS REMAINED THICK OVER MUCH OF THE COASTAL BASIN EARLY
THIS AFTERNOON IN TYPICAL MAY GRAY FASHION. SIGNIFICANT BREAKS WERE
EVIDENT IN SATELLITE IMAGERY ALONG THE IMMEDIATE COAST AND OFFSHORE.
PATCHY LIGHT PRECIPITATION WAS REPORTED FROM A HANDFUL OF REMOTE
RAIN GAGES...OTHERWISE MOST OF THE PRECIPITATION HAD ENDED BY NOON.
THE ONSHORE SFC PRESSURE GRADIENTS REMAINED IN THE 5-7 MB RANGE TO
THE DESERTS... WHICH CONTINUED TO SUPPORT LOCAL 40+ MPH WIND GUSTS
THROUGH THE WINDIER PASSES.

DESPITE THE CLEARING ALONG THE IMMEDIATE COAST...THERE WAS LITTLE
INDICATION THE CLEARING WOULD ADVANCE INLAND MUCH FARTHER TODAY. THE
MOIST LAYER IS QUITE DEEP AND WILL LIKELY REMAIN THROUGH SUNDAY WITH
ONLY PARTIAL CLEARING IN SOME AREAS. THIS WILL HOLD DAYTIME
TEMPERATURES WELL BELOW AVERAGE. A WIND ADVISORY REMAINS IN EFFECT
FOR THE SAN GORGONIO PASS AND THE SAN DIEGO COUNTY DESERTS THROUGH
TONIGHT. THESE WINDS HAVE WEAKENED A BIT THROUGH MIDDAY...BUT WILL
THEN INCREASE AGAIN TOWARD EVENING AND OVERNIGHT.

WATER VAPOR IMAGERY SHOWS A COMPACT WAVE NEAR CAPE MENDOCINO. THIS
FEATURE IS FORECAST TO DROP SE ACROSS THE STATE AND FORM A CLOSED
LOW OVER SE CA SUN MORNING. THIS WILL MAINTAIN THE VERY DEEP MOIST
LAYER OVER THE COASTAL BASIN AND SHOULD HELP TO WRING OUT MORE LIGHT
PRECIP WEST OF THE MTS. COOLING AND LIFT ASSOCIATED WITH THE LOW MAY
HELP TO BREAK UP THE CLOUD DECK A BIT MORE W OF THE MTS ON SUN. BUT
SUBSIDENCE AND WARMING ALOFT ON MEMORIAL DAY MAY REINFORCE THE LAYER
AS IT DECREASES FOR MORE LIMITED CLEARING AND CONTINUED BELOW
AVERAGE TEMPS...CLOSER TO THE COAST.

WEAK RIDGING WILL DEVELOP THROUGH THE MIDDLE OF NEXT WEEK...FOLLOWED
BY WEAK TROUGHING THROUGH THE END OF THE WEEK. THE NET RESULT IS
LITTLE CHANGE IN HEIGHTS...BUT A GRADUAL THICKNESS INCREASE FOR SLOW
WARMING INLAND AND A MORE SHALLOW MARINE LAYER. A CONTINUATION OF
ONSHORE FLOW AND A STRONGER...LOW INVERSION WILL INCREASE THE CHANCE
FOR MORE PERSISTENT CLOUD COVER AT THE BEACHES THROUGH THE DAY.  NO
SIGNIFICANT PRECIP IS EXPECTED NEXT WEEK.

&&

232000Z...LOW CLOUDS OVER THE COASTAL REGION TO AROUND 5 MILES
INLAND HAVE SCATTERED OUT...BUT STILL BKN/OVC OVER THE COASTAL
SLOPES OF THE MOUNTAINS AND INLAND VALLEYS. BASES 3500-4500 FT MSL
AND TOPS 5000-6000 FT MSL. LOW CLOUDS WILL REDEVELOP ALONG THE COAST
WITH SIMILAR BASES AND TOPS AFT 24/0000Z THIS EVENING. VIS P6SM
ALONG THE COAST AND DOWN TO 3-5SM WHERE CLOUDS INTERSECT TERRAIN.
DRIZZLE AND LIGHT RAIN IS POSSIBLE WEST OF THE MOUNTAINS AFT
24/0600Z TONIGHT.

WEST WINDS GUSTING TO 35-45 KT WILL CONTINUE TO BRING MOD-STG UDDFS
AND LLWS OVER AND EAST OF THE MTNS THROUGH TONIGHT.

&&

.MARINE...

200 PM...NO HAZARDOUS MARINE WEATHER IS EXPECTED THROUGH WEDNESDAY.

&&

.BEACHES...

200 PM...LONG-PERIOD SOUTH SWELLS ARRIVING ON SUNDAY WILL PEAK
MONDAY AT 3 FT WITH A PERIOD OF 16 SECONDS...AND GRADUALLY LOWER
TUESDAY INTO WEDNESDAY. THESE SWELLS WILL LIKELY PRODUCE STRONG RIP
AND LONGSHORE CURRENTS SUNDAY THROUGH MONDAY...WITH SOME ELEVATED
SURF IN ORANGE COUNTY AND NORTHERN SAN DIEGO COUNTY.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY UNTIL 2 AM PDT SUNDAY FOR SAN DIEGO COUNTY DESERTS-
     SAN GORGONIO PASS NEAR BANNING.

     BEACH HAZARDS STATEMENT FROM SUNDAY MORNING THROUGH MONDAY
     EVENING FOR ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY
     COASTAL AREAS.

PZ...NONE.
&&

$$

PUBLIC...JAD
AVIATION/MARINE/BEACHES...JT


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