Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 212155
AFDSGX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
155 PM PST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE PACIFIC THROUGH TUESDAY...BRINGING
WARMER CONDITIONS AND PERIODS OF GUSTY OF OFFSHORE WINDS NEAR THE
COASTAL FOOTHILLS.  THE STRONGEST OFFSHORE WINDS WILL OCCUR ON
MONDAY NIGHT AND TUESDAY MORNING...BEFORE WEAKENING INTO WEDNESDAY.
A TROUGH OF LOW PRESSURE WILL BRING COOLER CONDITIONS TO SOUTHERN
CALIFORNIA AND LOCALLY GUSTY WEST WINDS TO THE MOUNTAINS AND DESERTS
ON CHRISTMAS DAY.  HOWEVER...HIGH PRESSURE WILL REBUILD FOR THE
WEEKEND...WITH WARMER CONDITIONS AND MORE OFFSHORE WINDS POSSIBLE.

HAPPY WINTER SOLSTICE.  WINTER BEGINS AT 3:03 PM PST THIS AFTERNOON.

&&

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

WATER VAPOR IMAGERY SHOWS HIGH PRESSURE BUILDING ALONG 130 WEST THIS
AFTERNOON...WITH SOUTHERN CALIFORNIA UNDER MOIST NORTHWESTERLY FLOW
ALOFT.  AS A RESULT...HIGH CLOUD COVER CONTINUES TO SPILL INTO THE
REGION TODAY...BUT THERE ARE MORE SUN BREAKS AND WARMER CONDITIONS
PREVAILING.  TEMPERATURES ARE RUNNING A FEW DEGREES WARMER TODAY
THAN YESTERDAY...WHICH WILL MAKE FOR A PLEASANT EVENING.

THIS WARMING TREND ALONG WITH DEVELOPING OFFSHORE WINDS WILL BE THE
PREDOMINANT WEATHER STORY THROUGH TUESDAY...AS TEMPERATURES WILL RUN
BETWEEN 6 TO 12 DEGREES ABOVE NORMAL FOR BOTH MONDAY AND TUESDAY.
AS FOR THE WINDS...SURFACE GRADIENTS ARE CURRENTLY WEAKLY OFFSHORE
TO THE NORTH...BUT STILL ONSHORE TO THE EAST.  OFFSHORE GRADIENTS
WILL GRADUALLY INCREASE THROUGH MONDAY...THEN PEAK LATE MONDAY NIGHT
AND TUESDAY MORNING...BEFORE WEAKENING THROUGH WEDNESDAY.  THE UPPER
LEVEL SUPPORT ALSO REMAINS WEAK THROUGH MONDAY...BUT INCREASES
SIGNIFICANTLY MONDAY NIGHT AND TUESDAY MORNING.  THE 12Z NAM NOW
SHOWS 35 TO 45 KTS AT 850 MBS OVER THE SAN BERNARDINO AND SANTA ANA
MOUNTAINS BETWEEN 06Z AND 15Z ON TUESDAY...AND UP TO 50 KTS AT 925
MBS.  THE LOCAL WRF IS STRONGER...SO HAVE ISSUED A HIGH WIND WATCH
FOR MONDAY NIGHT AND TUESDAY.

A TROUGH OF LOW PRESSURE WILL THEN MOVE INLAND ACROSS THE PACIFIC
NORTHWEST LATE WEDNESDAY AND CHRISTMAS DAY...SQUASHING THE RIDGE
OVER SOUTHERN CALIFORNIA.  THIS WILL BRING COOLER CONDITIONS AND THE
RETURN OF ONSHORE FLOW TO THE REGION THROUGH FRIDAY.  SOME LOCALLY
GUSTY WINDS WILL BE POSSIBLE IN THE MOUNTAINS AND DESERTS THESE DAYS
AS WELL.  HIGH PRESSURE WILL THEN REBUILD ALONG THE WEST COAST FOR
NEXT WEEKEND...WITH WARMER CONDITIONS AND MORE OFFSHORE WINDS
POSSIBLE.

&&

.AVIATION...
212100Z...FEW LOW CLOUDS ALONG THE COAST THOUGH THIS EVENING. VIS
OF 5-6 SM HZ IN INLAND VALLEYS THROUGH THIS AFTERNOON.
OTHERWISE...SCT-BKN CLOUDS AOA 15 KFT MSL AND UNRESTRICTED VIS
THROUGH MON AFTERNOON.

&&

.MARINE...
100 PM...COMBINED SEAS TO 8 FEET WILL CONTINUE OVER PORTIONS OF THE
OUTER COASTAL WATERS THROUGH THIS AFTERNOON. OTHERWISE NO HAZARDOUS
MARINE WEATHER IS EXPECTED THROUGH FRIDAY.

&&

.BEACHES...
100 PM...A LARGE...LONG PERIOD WEST-NORTHWEST SWELL WILL CONTINUE
ELEVATED SURF THROUGH MONDAY MORNING...MAINLY IN SOUTHERN SAN DIEGO
COUNTY...AND STRONGER RIP CURRENTS THROUGH TUESDAY. IN
ADDITION...MORNING HIGH TIDES AROUND 7 FEET COULD CONTRIBUTE TO
MINOR TIDAL OVERFLOW THROUGH TUESDAY. SEE THE BEACH HAZARD STATEMENT
FOR DETAILS...LAXCFWSGX.

&&

.FIRE WEATHER...
OFFSHORE FLOW WILL DEVELOP ACROSS SOUTHERN CALIFORNIA FOR MONDAY
THROUGH WEDNESDAY...WITH PERIODS OF GUSTY NORTH TO NORTHEAST WINDS
POSSIBLE NEAR THE COASTAL FOOTHILLS.  WINDS WILL SLOWLY INCREASE
TONIGHT AND DURING THE DAY ON MONDAY...WITH THE STRONGEST WINDS AND
THE BEST UPPER LEVEL SUPPORT OCCURRING MONDAY NIGHT INTO TUESDAY.
MODERATE TO LOCALLY STRONG WINDS WILL BE POSSIBLE THROUGH AND BELOW
THE FAVORED PASSES AND CANYONS AS WELL AS ALONG THE COASTAL
FOOTHILLS MONDAY NIGHT THROUGH TUESDAY...BEFORE WEAKENING ON
WEDNESDAY.  DRIER AND WARMER CONDITIONS WILL DEVELOP THESE DAYS AS
WELL...WITH TEMPERATURES RUNNING AROUND 10 DEGREES ABOVE NORMAL AND
THE LOWEST DAY TIME HUMIDITY FALLING TO 10 TO 15 PERCENT FOR TUESDAY
AND WEDNESDAY. INCREASED FUEL MOISTURE DUE TO RECENT PRECIPITATION
WILL LIMIT THE POTENTIAL FIRE DANGER.

&&

.SKYWARN...
SKYWARN ACTIVATION WILL NOT BE NEEDED TODAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH WIND WATCH FROM MONDAY EVENING THROUGH TUESDAY AFTERNOON
     FOR THE COACHELLA VALLEY...ORANGE COUNTY COASTAL AREAS...
     RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO COUNTY
     MOUNTAINS...SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE
     INLAND EMPIRE...SAN DIEGO COUNTY MOUNTAINS...SAN DIEGO
     COUNTY VALLEYS...SANTA ANA MOUNTAINS AND FOOTHILLS.

     BEACH HAZARDS STATEMENT THROUGH TUESDAY MORNING FOR THE BEACHES
     IN THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY
     COASTAL AREAS.

PZ...NONE.

&&

$$

PUBLIC/FIRE WEATHER...PALMER
AVIATION/MARINE...JJT





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