Special Marine Warning 13, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
300 AM PST FRI DEC 12 2014

.SYNOPSIS...
A STRONG STORM SYSTEM WILL BRING GUSTY WINDS AND RAIN TODAY WITH A
PERIOD OF HEAVY RAIN LIKELY THIS MORNING. SCATTERED SHOWERS
WILL CONTINUE TONIGHT BEFORE ENDING EARLY SATURDAY.
SEVERAL INCHES OF SNOW WILL ACCUMULATE IN THE HIGHER ELEVATIONS OF
THE SAN BERNARDINO COUNTY MOUNTAINS. DRY WITH SEASONAL WEATHER LATE
SATURDAY THROUGH MONDAY. A SERIES OF TROUGHS WILL BRING PERIODS OF
RAIN MONDAY NIGHT INTO WEDNESDAY...POSSIBLY INTO THURSDAY.

&&

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

A NARROW BAND OF HEAVY PRECIPITATION WAS MOVING THROUGH EASTERN
VENTURA COUNTY AS OF 230 AM. RAINFALL RATES WITHIN THIS BAND WERE
GENERALLY BETWEEN ONE-HALF TO ONE INCH PER HOUR A MUCH LARGER SWATH
OF MODERATE TO HEAVY RAIN IS MOVING THROUGH SANTA BARBARA COUNTY.
FURTHER EAST OVER OUR FORECAST AREA...SCATTERED LIGHT SHOWERS HAVE
DEVELOPED IN THE RELATIVELY WARM SOUTHERLY FLOW AHEAD OF THE COLD
FRONT. MOSTLY TRACE AMOUNTS TO A COUPLE HUNDREDTHS OF AN INCH HAVE
BEEN REPORTED WITH THESE SHOWERS ALONG THE COAST AND THE SOUTH
SLOPES OF THE SAN BERNARDINO MOUNTAINS.

NO MAJOR CHANGES TO THE FORECAST THIS MORNING AS THINGS APPEAR TO BE
ON TRACK. GUSTY SOUTH WINDS HAVE DEVELOPED AHEAD OF THE FRONT AND
SHOULD CONTINUE TO STRENGTHEN AS THE FRONT APPROACHES. THE STRONG
SOUTHERLY LOW-LEVEL JET...VEERING WIND PROFILE...AND MODEST SURFACE
BASED CAPE WILL ARE FAVORABLE FOR THUNDERSTORMS THIS
MORNING...MAINLY OVER THE COASTAL WATERS AND ADJACENT COASTAL AREAS.
WATERSPOUTS AND/OR WEAK TORNADOES ARE NOT OUT OF THE QUESTION. THIS
THREAT SHOULD QUICKLY END BY ABOUT 10 AM AS LOW-LEVEL WINDS BECOME
WESTERLY.

FOR THE STORM TODAY...

WIND: STRONG SOUTH-SOUTHEAST WINDS AHEAD OF THE COLD FRONT WILL
CONTINUE THROUGH ABOUT 10 AM FRIDAY. A PERIOD OF SUSTAINED WINDS OF
20-30 MPH WITH GUSTS OF 40-45 MPH IS LIKELY DURING THIS TIME. WINDS
WILL BECOME WESTERLY AND WEAKEN SUBSTANTIALLY WITH THE PASSAGE OF
THE COLD FRONT LATER THIS MORNING.

RAINFALL: ISOLATED LIGHT SHOWERS EARLY THIS MORNING WILL BE FOLLOWED
BY WIDESPREAD MODERATE TO LOCALLY HEAVY RAIN BETWEEN ABOUT 4 AM AND
10 AM. STRATIFORM PRECIPITATION WILL TURN TO SHOWERS THIS AFTERNOON
AND GRADUALLY TAPER OFF TONIGHT INTO SATURDAY MORNING. COLD AIR
ALOFT WILL MOVE OVER THE REGION THIS EVENING...INCREASING
INSTABILITY AND ENHANCING THE THREAT OF THUNDERSTORMS. WHILE SHOWERS
THIS EVENING SHOULD BE LIGHT FOR THE MOST PART...ISOLATED MODERATE
TO HEAVY SHOWERS AND SMALL HAIL ARE POSSIBLE SHOULD ANY
THUNDERSTORMS DEVELOP. OTHERWISE THE HIGHEST RAINFALL AMOUNTS ARE
EXPECTED ALONG THE SOUTH SLOPES OF THE SAN BERNARDINO MOUNTAINS
WHERE STRONG SOUTH WINDS ENHANCE OROGRAPHIC PRECIPITATION.

STORM TOTAL RAINFALL AMOUNTS WILL BE AROUND 1-1.50 INCHES IN THE
ORANGE COUNTY COASTAL AREAS AND INLAND EMPIRE...0.75-1.25 INCHES IN
THE SAN DIEGO COUNTY COASTS AND VALLEYS...1.5-2.00 INCHES IN THE
MOUNTAINS...AND 0.25-0.50 INCHES IN THE DESERTS. LOCAL AMOUNTS OF
3-4 INCHES ARE POSSIBLE ON THE SOUTH SLOPES OF THE SAN BERNARDINO
MOUNTAINS.

SNOWFALL: SNOW LEVELS WILL FALL FROM 8000 FEET THIS MORNING TO
5500-6500 FEET THIS AFTERNOON...THEN 5000-5500 FEET FRIDAY NIGHT.
2-5 INCHES OF SNOW IS POSSIBLE OVER THE SAN BERNARDINO
MOUNTAINS...WITH LOCALLY HIGHER AMOUNTS ON HIGHEST PEAKS. 1-2 INCHES
ARE POSSIBLE ON THE HIGHER PEAKS OF THE SAN JACINTO MOUNTAINS...AND
ONLY TRACE AMOUNTS ABOVE 5500 FT IN SAN DIEGO COUNTY.

WEAK RIDGING WILL BRING DRY...MILD WEATHER SUNDAY INTO MONDAY.
ANOTHER TROUGH DIGS ALONG THE WEST COAST BY MONDAY...AND SEVERAL
SHORT WAVES MOVING INTO SOUTHERN CA WILL BRING PERIODS OF
PRECIPITATION LATE MONDAY INTO AT LEAST WEDNESDAY. THE TIMING AND
TRACK OF THE MAIN UPPER LOW AND LONG-WAVE TROUGH AXIS IS ALL OVER
THE PLACE...SO CONFIDENCE LOWERS RAPIDLY TOWARDS THE END OF THE
FORECAST PERIOD. SHOWERS COULD CONTINUE INTO THU...OR WE COULD BE
WARMER AND DRY UNDER OFFSHORE FLOW.

&&

.AVIATION...
121000Z...LOW CLOUDS WITH BASES 2500-3500 FT MSL AND TOPS NEAR 4500
FT MSL...WILL CONTINUE WEST OF THE MOUNTAINS EARLY THIS MORNING.
REDUCED VIS AND LOWER CIGS ARE LIKELY BETWEEN 1500 UTC AND 2100 UTC
DURING RAIN SHOWERS. SCT TSTMS WILL ALSO BE POSSIBLE DURING THIS
PERIOD. VARIABLE CIGS WILL CONTINUE THROUGH TONIGHT.

SOUTH WINDS GUSTING TO NEAR 35 KTS WILL LIKELY IMPACT AIRPORTS WEST
OF THE MTNS BETWEEN 1200 UTC AND 1800 UTC...WHILE PORTIONS OF THE
MOUNTAINS AND DESERTS COULD EXPERIENCE GUSTS NEAR 50 KTS. WINDS WILL
SLOWLY DIMINISH THROUGH THE DAY...BECOMING WESTERLY IN THE
AFTERNOON AFTER THE FRONT PASSES.

&&

.MARINE...
200 AM...SEAS WILL CONTINUE TO RISE THROUGH SATURDAY AS A SERIES OF
ELEVATED WEST-NORTHWEST SWELLS ENTER THE REGION. AS THE LARGEST
SWELLS ENTER THE COASTAL WATERS THIS MORNING...COMBINED SEAS OF 10
TO 13 FEET WILL BE POSSIBLE THROUGH SATURDAY...MAINLY OVER THE OUTER
COASTAL WATERS. SOUTH WINDS GUSTING NEAR 35 KT ARE EXPECTED AHEAD OF
THE COLD FRONT THIS MORNING...WITH WEST WINDS GUSTING TO NEAR 20 KT
BEHIND THE FRONT EARLY THIS AFTERNOON AND EVENING. CONDITIONS WILL
LIKELY BE HAZARDOUS TO SMALL CRAFT DURING THIS TIME. WINDS WILL
CONTINUE TO WEAKEN ON SATURDAY. A SMALL CRAFT ADVISORY REMAINS IN
EFFECT THROUGH SATURDAY MORNING FOR THE SEAS AND WIND.

ISOLATED THUNDERSTORMS ARE POSSIBLE THIS MORNING AS THE COLD
FRONT MOVES ACROSS THE COASTAL WATERS. CLOUD-TO-WATER
LIGHTNING...SMALL HAIL...HEAVY RAIN...GUSTY AND ERRATIC WINDS...AND
WATERSPOUTS WILL BE POSSIBLE NEAR THUNDERSTORMS. A MARINE WEATHER
STATEMENT HAS BEEN ISSUED FOR THE COASTAL WATERS FOR TODAY AND
TONIGHT.

&&

.BEACHES...
200 AM...SURF WILL CONTINUE TO INCREASE ALONG SAN DIEGO AND ORANGE
COUNTY BEACHES THIS MORNING...BECOMING 7 TO 10 FEET WITH LOCAL SETS
TO 14 FEET. STRONG RIP CURRENTS ARE EXPECTED THROUGH THE
WEEKEND...WITH BEACH EROSION POSSIBLE TODAY AND SATURDAY. SWELL AND
SURF WILL BEGIN TO SUBSIDE EARLY NEXT WEEK.

&&

.SKYWARN...
SKYWARN ACTIVATION MAY BE REQUESTED EARLY THIS MORNING. WEATHER
SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WIND ADVISORY UNTIL 10 AM PST FRIDAY FOR THE ORANGE COUNTY
     COASTAL AREAS...SAN BERNARDINO AND RIVERSIDE COUNTY
     VALLEYS-THE INLAND EMPIRE...SAN DIEGO COUNTY COASTAL
     AREAS...SAN DIEGO COUNTY VALLEYS...SANTA ANA MOUNTAINS AND
     FOOTHILLS.

     BEACH HAZARDS STATEMENT THROUGH LATE TONIGHT FOR THE BEACHES IN
     THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL
     AREAS.

     HIGH SURF ADVISORY FROM 4 AM FRIDAY TO 10 PM PST SATURDAY FOR
     THE ORANGE COUNTY COASTAL AREAS...SAN DIEGO COUNTY COASTAL
     AREAS.

     WINTER WEATHER ADVISORY FROM 6 AM FRIDAY TO 6 AM PST SATURDAY
     FOR THE SAN BERNARDINO COUNTY MOUNTAINS.

     HIGH WIND WARNING UNTIL 10 AM FRIDAY FOR THE APPLE AND LUCERNE
     VALLEYS...SAN BERNARDINO COUNTY MOUNTAINS.

     FLASH FLOOD WATCH FROM LATE TONIGHT THROUGH LATE FRIDAY NIGHT
     FOR THE SAN DIEGO COUNTY VALLEYS...SANTA ANA MOUNTAINS AND
     FOOTHILLS.

PZ...SMALL CRAFT ADVISORY UNTIL 10 AM PST SATURDAY 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...22
AVIATION/MARINE/BEACHES...PG