Weather Service Report


065 
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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