Frost Advisory 6, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
804 PM PST THU DEC 25 2014

.SYNOPSIS...
COOL CONDITIONS CONTINUE...WITH PERIODS OF GUSTY NORTHEAST WINDS
ACROSS THE REGION THIS HOLIDAY WEEKEND. ALTHOUGH CONDITIONS MAY
MODERATE A BIT ON SUNDAY...A VERY COLD AIRMASS AND LOW PRESSURE
SYSTEM WILL DIG OVER THE WEST FOR EARLY NEXT WEEK THROUGH NEW YEARS
DAY. THIS SYSTEM WILL EITHER BRING THE REGION COLD TEMPERATURES AND
STRONG SANTA ANA WINDS OR IF IT BECOMES STRONG ENOUGH AND DEVELOPS
FURTHER WEST IT WOULD HAVE THE POTENTIAL TO BRING RAIN AND VERY LOW
ELEVATION SNOWFALL. EITHER WAY...EXPECT UNSEASONABLY COLD WEATHER TO
CONTINUE AT LEAST THROUGH NEW YEARS DAY.

&&

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

CUMULUS CLOUDS QUICKLY DRIED OUT AFTER SUNSET ACROSS SAN DIEGO
COUNTY AND SKY CONDITIONS ARE GENERALLY CLEAR THROUGHOUT THE
REGION.

OFFSHORE PRESSURE GRADIENTS ARE ON THE RISE THIS EVENING. ALTHOUGH
WIND SPEEDS ARE STILL MODERATE...EXPECT AN INCREASE IN GUSTY
NORTHEAST WINDS AFTER MIDNIGHT WITH GUSTS UP TO 60 MPH POSSIBLE AT
TIMES. A WIND ADVISORY REMAINS IN EFFECT THROUGH SATURDAY MORNING
FOR ORANGE AND SAN BERNARDINO COUNTIES. PERIODS OF STRONG OFFSHORE
FLOW WILL CONTINUE THROUGH SATURDAY. TEMPERATURES WILL BOTTOM OUT
FRIDAY NIGHT IN THE HIGH DESERTS IN THE LOW TO MIDDLE 20S AND IN THE
LOW TO MIDDLE 30S IN THE VALLEYS.

ATTENTION IS TURNING TOWARDS A STRONG AND VERY COLD LOW PRESSURE
SYSTEM EARLY NEXT WEEK THROUGH NEW YEARS. THE MODELS ARE BEGINNING
TO HAVE SOME AGREEMENT IN THIS RELATIVELY NEW PATTERN. LOOKING AT
THE GEFS ENSEMBLES AND THE ANALOG TOOL WHICH TAKES THE ENSEMBLE
FORECAST AND COMPARES IT TO HISTORICAL DATASETS...FORECASTER
CONFIDENCE IS INCREASING IN THE VERY COLD UPPER LOW RETROGRADING A
BIT ACROSS FAR SOUTHERN CALIFORNIA TUESDAY AND INTO NEW YEARS EVE.
IF THIS PATTERN VERIFIES WE COULD SEE VERY LOW SNOW LEVELS AS LOW AS
2000-2500 FEET AND STRONG WINDS FROM TUESDAY NIGHT INTO WEDNESDAY
NIGHT. COLD AIRMASS WOULD CONTINUE INTO NEW YEARS DAY. FOR NOW WE
HAVE ADJUSTED THE POPS UP A BIT FOR TUE-WED AND LOWERED SNOW LEVELS
A BIT. ATTM THE ECM IS FURTHER EAST WITH THE COLD CORE AND THE GFS
TRACKS THE LOW DIRECTLY OVER OUR REGION. MEANWHILE THE GEFS LENDS
MORE CREDIBILITY TO THE GFS FORECAST. LATER FORECASTS WILL FINE TUNE
TOWARDS FORECASTER CONFIDENCE IN THIS POTENTIALLY SIGNIFICANT
WEATHER MAKER FOR OUR REGION.

&&

.AVIATION...
260400Z...CLEAR SKIES WITH UNRESTRICTED VIS WILL PREVAIL THROUGH FRI
NIGHT. SURFACE WINDS FROM THE NORTH TO NORTHEAST WILL CONTINUE
THROUGH FRI NIGHT MAINLY IN THE SANTA ANA MOUNTAINS...INLAND EMPIRE
AND LOWER DESERTS WITH GUSTS 30-40 KT...INCLUDING VCNTY
KONT...KSBD...KRAL... KCNO...WITH LLWS AND STRONG UP/DOWNDRAFTS.

&&

.MARINE...
800 PM...WINDS HAVE INCREASED AGAIN IN THE COASTAL WATERS...AND
WINDS WILL GUST AROUND OR JUST OVER 25 KT IN SOME AREAS THROUGH
EARLY FRIDAY. WIND DIRECTION WILL BE NORTHERLY...TRENDING NORTHEAST
EARLY FRIDAY MORNING DUE TO THE OFFSHORE FLOW. A SMALL CRAFT
ADVISORY IS IN EFFECT FOR THE INNER AND OUTER COASTAL WATERS THROUGH
8 AM PST FRIDAY.

&&

.BEACHES...
800 PM...A LONG-PERIOD WEST-NORTHWEST WILL CONTINUE ELEVATED SURF OF
3-5 FEET...WITH OCCASIONAL SETS TO 6 FEET...AND STRONG RIP CURRENTS
AT THE SAN DIEGO AND ORANGE COUNTY BEACHES THROUGH FRIDAY. SWELL AND
SURF WILL SUBSIDE OVER THE WEEKEND.

&&

.FIRE WEATHER...
PERIODS OF GUSTY NORTH TO NORTHEAST WINDS WILL PREVAIL ACROSS THE
COASTAL MOUNTAIN SLOPES AND ADJACENT FOOTHILL AREAS IN ORANGE AND
SOUTHWESTERN SAN BERNARDINO COUNTIES THROUGH SATURDAY MORNING.
SOMEWHAT WEAKER GUSTY NORTHEAST WINDS ARE POSSIBLE IN THE MOUNTAINS
AND INLAND COASTAL AREAS OF RIVERSIDE AND SAN DIEGO COUNTIES FOR
FRIDAY INTO SATURDAY. BELOW AVERAGE TEMPERATURES WILL CONTINUE INTO
THE WEEKEND WITH LOWEST INLAND HUMIDITIES ON FRIDAY AND SATURDAY OF
15 TO 25 PERCENT.  WETTING RAINS MAY BE POSSIBLE EARLY NEXT WEEK.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...SMALL CRAFT ADVISORY FOR WINDS UNTIL 8 AM PST FRIDAY FOR THE
SAN      DIEGO COUNTY COASTAL AREAS.

     WIND ADVISORY UNTIL NOON PST SATURDAY FOR THE ORANGE COUNTY
     COASTAL AREAS...SAN BERNARDINO COUNTY MOUNTAINS...SAN
     BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE...
     SANTA ANA MOUNTAINS AND FOOTHILLS.

PZ...SMALL CRAFT ADVISORY FOR WINDS UNTIL 8 AM PST FRIDAY FOR THE
     COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
     AND OUT 30 NM...WATERS FROM SAN MATEO POINT TO THE MEXICAN
     BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN CLEMENTE
     ISLAND.

&&

PUBLIC...BROTHERTON
FIRE WEATHER...PALMER
AVIATION/MARINE...MAXWELL