Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 121637
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PDT SAT JUL 12 2014

.SYNOPSIS...
EXPECT FAIR WEATHER TODAY WITH LOW CLOUDS CLEARING BACK TO THE COAST
LATER THIS MORNING...AND TEMPERATURES AT OR A FEW DEGREES ABOVE
SEASONAL AVERAGES. A LITTLE WARMER IN MOST AREAS FOR SUNDAY THROUGH
TUESDAY WITH DECREASING MARINE LAYER LOW CLOUDS OVER THE COASTAL
AREAS DURING THE NIGHTS AND MORNINGS. AN INFLUX OF SUB-TROPICAL
MOISTURE WILL BRING CHANCES FOR SHOWERS AND THUNDERSTORMS...MAINLY
OVER THE MOUNTAINS AND POSSIBLY THE DESERTS. MOISTURE AND CHANCES
FOR CONVECTION DECREASE LATER IN THE WEEK...BUT DAYTIME TEMPERATURES
REMAIN SOMEWHAT ABOVE SEASONAL AVERAGES...AND THE MARINE LAYER
INCREASES.

&&

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

MARINE LAYER LOW CLOUDS HAD SPREAD INLAND TO THE FOOTHILLS OF SAN
DIEGO COUNTY...BUT ARE NOW IN THE PROCESS OF BURNING OFF AND SHOULD
CLEAR TO THE COAST BEFORE 11 AM. SATELLITE IMAGERY ALSO SHOWS
VARIABLE HIGH CLOUDS ARE MOVING IN FROM THE SOUTHEAST. THE MORNING
SOUNDING FROM NKX SHOWS THE MARINE LAYER ABOUT 2000 FT DEEP WITH NW
WINDS AND LOW HUMIDITIES ABV A WEAK INVERSION. THE DRY CONDITIONS
ALOFT...ALONG WITH MID LEVEL WARMING WILL SUPPRESS DEEP CONVECTION
FOR TODAY.

THROUGH WEDNESDAY...A WARMING TREND BEGINS TODAY AS THE UPPER LEVEL
RIDGE OF HIGH PRESSURE EXPANDS WESTWARD OVER SOCAL. THE RIDGE AXIS
SHIFTS NORTHWARD ON SUN...ALLOWING SE FLOW TO BEGIN ADVECTING
SUB-TROPICAL MOISTURE INTO THE REGION. THE DEEP-LAYER MOISTURE WILL
BE LIMITED ON SUN...BRINGING ONLY SMALL CHANCES FOR THERMALLY DRIVEN
SHOWERS AND TSTMS OVER THE MTNS DURING THE AFTERNOON/EVENING.
CHANCES FOR DEEP CONVECTION INCREASE ON MON THROUGH WED AS A
TROPICAL WAVE MOVES IN FROM THE SOUTHEAST. THIS WILL INCREASE THE
CHANCES FOR SHOWERS AND TSTMS OVER THE MTNS AND DESERTS.

THE INCREASING HEIGHTS AND SE FLOW ALOFT WILL REDUCE THE MARINE
LAYER...RESULTING IN ONLY PATCHY LOW CLOUDS OVER THE COASTAL AREAS
DURING THE NIGHTS AND MORNINGS.

FOR THU THROUGH SAT...A SHIFT IN THE POSITION OF THE UPPER LEVEL
RIDGE WILL BRING A REDUCTION IN MONSOONAL MOISTURE...DECREASING THE
CHANCES FOR DEEP CONVECTION ALTHOUGH IT CANNOT BE RULED OUT. THE
MARINE LAYER WILL LIKELY DEEPEN ONCE MORE...INCREASING THE LOW CLOUD
COVERAGE OVER THE COASTAL AREAS DURING THE NIGHTS AND MORNINGS.

&&

.AVIATION...
121600...COAST/VALLEYS...LOW CLOUDS WITH BASES AROUND 1500 FEET
MSL...TOPS AROUND 2000 FEET MSL...AND EXTENDING INLAND ABOUT 10
MILES...WILL SPREAD BACK TO THE COAST BY AROUND 1630Z-1730Z THIS
MORNING. CONFIDENCE IN CLEARING TIME IS ONLY GOOD AS HIGH CLOUDS MAY
DELAY CLEARING TIME IN COMPARISON TO FORECASTS.

THE LOW CLOUDS WILL BE RETURNING TO THE COASTAL AIRPORTS AFTER
03Z...AND REACHING INLAND TO KRNM AND JUST WEST OF KONT BY EARLY
SUNDAY MORNING. SIMILAR BASES AND TOPS ARE EXPECTED. OTHERWISE...
SCT-BKN CLOUDS ABOVE 20000 FT MSL THROUGH THIS EVENING.

MTNS/DESERTS...SCT-BKN CLOUDS ABOVE 20000 FT MSL AND UNRESTRICTED
VIS THROUGH SUN MORNING.

&&

.MARINE...
800 AM...NO HAZARDOUS MARINE WEATHER CONDITIONS EXPECTED THROUGH
WEDNESDAY.

&&

.BEACHES...
HIGH TIDES WILL BE NEAR TO SLIGHTLY ABOVE 7 FEET FOR THE OPEN
COASTLINE DURING THE MID TO LATE EVENINGS THROUGH SUNDAY...WHICH
COULD RESULT IN LOCAL MINOR TIDAL OVERFLOW OF LOW-LYING BEACH AREAS.
A BEACH HAZARDS STATEMENT CONTINUES THROUGH SUNDAY EVENING. HIGH
TIDES SHOULD LOWER ENOUGH BY MONDAY FOR THE TIDAL FLOODING THREAT TO
BE DIMINISHING.

&&

.SKYWARN...
SPOTTER ACTIVATION WILL NOT BE NEEDED AT THIS TIME.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...BEACH HAZARDS STATEMENT THROUGH SUNDAY EVENING FOR THE BEACHES
     IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY
     COASTAL AREAS.

PZ...NONE.

&&

$$

PUBLIC...PG
AVIATION/MARINE...SMALL




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