Small Craft Advisory 16, NWS San Diego, CA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 AM PDT TUE OCT 8 2013

.SYNOPSIS...
A LOW PRESSURE TROUGH DEEPENING OVER THE PACIFIC NORTHWEST TODAY
WILL MOVE RAPIDLY SOUTH DOWN THE WEST COAST TONIGHT. ON WEDNESDAY
THE STORM WILL BRING RAIN...GUSTY WINDS AND HIGH ELEVATION MOUNTAIN
SNOW AS IT MOVES ACROSS SOUTHERN CALIFORNIA. THE STORM WILL MOVE
EAST THURSDAY FOLLOWED BY DRY...WARMER WEATHER FRIDAY THROUGH
SUNDAY.

&&

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

A WEST COAST TROUGH WILL BRING COOLING...GUSTY WINDS AND A STEADILY
DEEPENING MARINE LAYER TODAY. A WEAK COASTAL EDDY WILL ALSO ENHANCE
MARINE LAYER GROWTH WHICH WILL LIKELY BE 5000 FEET DEEP BY WEDNESDAY
MORNING. DEWPOINTS IN THE COASTAL AREAS HAVE RECOVERED INTO THE 50S
THIS MORNING AND THAT RECOVERY WILL SPREAD INTO THE VALLEYS AND
COASTAL MOUNTAIN SLOPES TODAY AND TONIGHT AS THE MARINE LAYER
DEEPENS. WESTERLY WINDS HAVE ALREADY STARTED RAMPING UP IN THE
MOUNTAINS AND DESERTS WITH GUSTS FROM 25-35 MPH IN SOME AREAS.

THE COLD UPPER LOW OVER WESTERN CANADA THIS MORNING WILL RAPIDLY
MOVE DOWN THE WEST COAST TONIGHT AND WEDNESDAY. WINDS ACROSS
RIVERSIDE AND SAN DIEGO COUNTIES WILL STRENGTHEN TO ADVISORY
STRENGTH TONIGHT WITH 20-30 MPH WINDS GUSTING TO 50 MPH. FURTHER
STRENGTHENING WILL TAKE PLACE WEDNESDAY AND WEDNESDAY EVENING AS A
STRONG 120KT 300 MB JET TRACKS ACROSS FAR SOUTHERN CALIFORNIA. A
HIGH WIND WATCH IS IN EFFECT FOR THE MOUNTAINS AND DESERTS
WEDNESDAY.

THE 12Z MODEL OUTPUT IS CONSISTENT WITH PREVIOUS RUNS WITH THE STORM
TRACK AND INTENSITY WHICH ADDS CONFIDENCE TO THE FORECAST. LOW LEVEL
MOISTURE STEADILY INCREASES AHEAD OF THE TROUGH WEDNESDAY...ALONG
WITH A NARROW BAND OF HIGHER PRECIPITABLE WATER VALUES FROM
0.80-0.90" THAT WILL MOVE ACROSS SOCAL WEDNESDAY AFTERNOON. LIGHT
PRECIPITATION WILL BEGIN OVER THE REGION LATE TONIGHT/EARLY
WEDNESDAY...THEN STEADILY INCREASE DURING THE DAY AS THE STORM NEARS.

THE MAIN PERIOD OF PRECIPITATION WILL BE WEDNESDAY AFTERNOON AND
WEDNESDAY EVENING ALONG AND AHEAD OF THE COLD FRONT. UPPER
DIVERGENCE ASSOCIATED WITH THE LEFT FRONT EXIT REGION OF A
CYCLONICALLY CURVED UPPER JET ALONG WITH STRONG OROGRAPHIC LIFT ON
THE SOUTHWEST FACING SLOPES WILL FOCUS HIGHER PRECIP AMOUNTS AND
RAIN RATES ON SOUTH SLOPES OF THE SAN BERNARDINO COUNTY MOUNTAINS
WHERE OVER AN INCH IN EXPECTED. ELSEWHERE...RAINFALL AMOUNTS WILL
RANGE FROM ONE TENTH TO LOCALLY ONE QUARTER INCH NEAR THE COAST TO
ONE HALF TO LOCALLY ONE INCH IN THE MOUNTAINS. ONE TENTH INCH OR
LESS IS FORECAST FOR THE DESERTS.

THIS UNUSUALLY STRONG EARLY SEASON STORM WILL BE COLD ENOUGH FOR
SNOW IN THE MOUNTAINS ABOVE 5500-6000 FEET. THE BEST CHANCE FOR
ACCUMULATING SNOW WILL BE IN THE SBD AND RIV COUNTY MOUNTAINS WHERE
SEVERAL INCHES WILL ACCUMULATION ABOVE 6000 FEET. LOCAL AMOUNTS OF 4
TO 8 INCHES ARE POSSIBLE ABOVE 8000 FEET.

SHOWERS WILL DECREASE AND END FROM THE NORTH WEDNESDAY NIGHT AND
LINGER THE LONGEST IN SAN DIEGO COUNTY THROUGH EARLY THURSDAY
MORNING.

.FROM PREVIOUS DISCUSSION.

.LONG TERM (FRIDAY THROUGH MONDAY)...
A GENERAL WEST NORTHWEST FLOW PATTERN WILL PREVAIL WITH SHORTWAVES
MOVING BY TO THE NORTH. ON SUCH LOW PRESSURE SYSTEM WILL MOVE
THROUGH THE PACIFIC NORTHWEST SUNDAY INTO THE GREAT BASIN MONDAY AND
NORTHERN AND CENTRAL ROCKIES TUESDAY WITH SOME SPREAD AMONG THE
GLOBAL MODELS ON THE TIMING AND AMPLITUDE OF THIS SYSTEM. FOR
SOUTHERN CALIFORNIA...IT SHOULD BE DRY WITH HIGH TEMPERATURES SLOW
WARMING TOWARD SEASONAL LEVELS. THERE COULD BE SOME HIGH CLOUDS AT
TIMES AND SOME PATCHY STRATUS IS POSSIBLE NEAR THE COAST.

&&

.AVIATION...
081511Z...COAST/VALLEYS/MTNS...PATCHY STRATUS 20-25 SM INLAND...WITH
BASES 1600-2100 FT MSL AND TOPS 2200-2500 FT MSL...WILL SLOWLY CLEAR
TO THE COAST THROUGH 1800 UTC. ELSEWHERE...SKC AND UNRESTRICTED VIS
WILL CONTINUE. 1800-09/0000 UTC...SKC AND UNRESTRICTED VIS...EXCEPT
WITHIN 5 SM OF THE COAST WHERE SCT-BKN CLDS 2000-2500 FT MSL MAY
OCCUR...POSSIBLY BRINGING BKN CIGS TO KSAN...KCRQ AND KSNA AT TIMES.
09/0000-0600 UTC...STRATUS WILL MOVE INLAND QUICKLY...AND MAKE IT
35-50 SM INLAND BY 09/0900 UTC. BASES WILL BE 2500-3000 FT MSL AND
TOPS AROUND 4000 FT MSL. MTN OBSCURATION WILL OCCUR ALONG THE
COASTAL SLOPES DUE TO CLDS/DZ. ISOL-SCT -SHRA WILL START TO MOVE IN
AFTER 09/0900 UTC...BRINGING LOCAL VIS/CIGS OF 3-5SM/1500 FT AGL.

DESERTS...MOSTLY SKC WITH UNRESTRICTED VIS THROUGH EARLY WEDNESDAY
MORNING.

&&

.MARINE...
A COLD FRONT WILL BRING STRONGER WEST AND SOUTHWEST WINDS WEDNESDAY
INTO THURSDAY OVER THE COASTAL WATERS...WITH GUSTS OF 25 TO 30 KNOTS
LIKELY. THE STRONGEST WINDS WILL OCCUR WEDNESDAY EVENING. A 4-6
FOOT SHORT-PERIOD SWELL WILL ACCOMPANY THE WINDS. A SMALL CRAFT
ADVISORY WILL LIKELY BE NEEDED FOR THE WEDNESDAY AFTERNOON THROUGH
EARLY THURSDAY MORNING TIME-PERIOD.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...WINTER WEATHER ADVISORY FROM NOON TO 10 PM PDT WEDNESDAY ABOVE
     6000 FEET FOR THE RIVERSIDE COUNTY MOUNTAINS...SAN
     BERNARDINO COUNTY MOUNTAINS.

     WIND ADVISORY FROM 5 PM THIS AFTERNOON TO 5 AM PDT WEDNESDAY
     FOR THE COACHELLA VALLEY...RIVERSIDE COUNTY MOUNTAINS... SAN
     DIEGO COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS.

     HIGH WIND WATCH FROM LATE TONIGHT THROUGH LATE WEDNESDAY NIGHT
     FOR THE COACHELLA VALLEY...RIVERSIDE COUNTY MOUNTAINS...SAN
     DIEGO COUNTY DESERTS...SAN DIEGO COUNTY MOUNTAINS.

     HIGH WIND WATCH FROM LATE TONIGHT THROUGH WEDNESDAY EVENING FOR
     THE APPLE AND LUCERNE VALLEYS...SAN BERNARDINO COUNTY
     MOUNTAINS.

PZ...NONE.

&&

PUBLIC...MOEDE
AVIATION/MARINE...HARRISON