Area Forecast Discussion
Issued by NWS Los Angeles, CA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS66 KLOX 220010
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
410 PM PST SUN DEC 21 2014

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...
HIGH PRESSURE WILL BRING WARMER AND DRY CONDITIONS TO SOUTHERN
CALIFORNIA MONDAY THROUGH WEDNESDAY. GUSTY NORTHWEST TO NORTH WINDS
WILL AFFECT PARTS OF THE REGION TONIGHT...THEN NORTHEAST WINDS WILL
AFFECT VENTURA AND LOS ANGELES COUNTIES MONDAY NIGHT THROUGH
TUESDAY. SLIGHTLY COOLER CONDITIONS ARE EXPECTED FOR CHRISTMAS DAY
INTO NEXT WEEKEND.

&&

.SHORT TERM (TONIGHT-WED)...
STRONG NORTHERLY FLOW ALOFT CONTINUES TO STREAM MOISTURE INTO
SOUTHWEST CALIFORNIA. A PERSISTENT MOUNTAIN WAVE BROUGHT MOSTLY
CLOUDY SKIES ACROSS VENTURA AND PARTS OF LOS ANGELES COUNTY. WE ALSO
HAD MOISTURE PUSH INTO THE SAN LUIS AND SANTA BARBARA COUNTY
MOUNTAINS WHERE A FEW SPRINKLES CONTINUED THIS AFTERNOON.

FOR TONIGHT NORTH WINDS WILL BE THE MAIN ISSUE WITH WIND ADVISORIES
CONTINUING INTO MONDAY MORNING FROM THE SANTA YNEZ MOUNTAINS AND
SOUTH COAST OF SANTA BARBARA COUNTY...ACROSS THE VENTURA AND LOS
ANGELES COUNTY MOUNTAINS...INCLUDING THE SANTA MONICA MOUNTAINS.
THERE WILL ALSO BE A FEW GUSTS TO 35 MPH IN THE SAN FERNANDO VALLEY
PRIOR TO SUNSET. THE JET STREAM AXIS SHIFTS EASTWARD LATE TONIGHT SO
CLOUDS SHOULD SLOWLY DISSOLVE OVERNIGHT. A FEW LINGERING SHOWERS ARE
POSSIBLE ON THE NORTH SLOPES OF THE MOUNTAINS THROUGH MIDNIGHT
HOWEVER. PATCHY DENSE FOG WILL RETURN TO THE SALINAS VALLEY FOR
MONDAY MORNING AS WELL.

ON MONDAY THE NORTH WINDS WILL TAPER DOWN FAIRLY EARLY IN THE
MORNING. HIGH PRESSURE BUILDS INTO THE NORTHERN ROCKIES WITH A LOW
PRESSURE TROUGH EXTENDING JUST OFF THE CA COAST. THIS OFFSHORE
WEATHER PATTERN SHOULD RESULT IN MORE SUNSHINE AND WARMER
TEMPERATURES FOR VALLEYS AND COASTS...EVEN THE CENTRAL COAST WILL
SEE SIGNIFICANT WARMING ON MONDAY. A SANTA ANA WIND REGIME DEVELOPS
LATE MONDAY AS WINDS TURN NORTHEASTERLY AND OFFSHORE PRESSURE
GRADIENTS BECOME -6 MB LAX-DAG AND -11 MB LAX-TPH. MODELS SHOW
LOW-LEVEL WINDS PEAKING AROUND 45KTS IN THE BEST CORRIDORS OF
EASTERN VENTURA AND WESTERN LOS ANGELES COUNTIES TUESDAY MORNING.
WINDS ABOVE RIDGETOPS ARE NOT ALIGNED ALL THAT WELL AND COLD
ADVECTION LOOKS WEAK AT THIS POINT. ANTICIPATE WE WILL NEED TO
REISSUE SOLID WIND ADVISORIES FOR THE VENTURA AND LOS ANGELES COUNTY
MOUNTAINS AND VALLEYS...AND POSSIBLY INTO COASTAL AREAS FOR LATE
MONDAY NIGHT AND TUESDAY. NOT BEING A VERY COLD SANTA ANA...WE
SHOULD SEE TEMPERATURES CLIMB 10-15 DEGREES BY TUESDAY COMPARED TO
TODAY FOR MANY VALLEYS AND COASTS.

TUESDAY NIGHT AND WEDNESDAY THE SANTA ANA IS MUCH WEAKER WITH LOCAL
ADVISORY LEVEL WINDS IN THE SANTA CLARITA AND VENTURA COUNTY
VALLEYS. PRESSURE GRADIENTS SHOW -5 MB LAX-DAG AND ONLY A -4 MB
LAX-TPH FOR WEDNESDAY MORNING. EXPECT WINDS TO RAPIDLY DECREASE ON
WEDNESDAY WITH TEMPERATURES REMAINING ABOVE NORMAL AND NEARLY AS
WARM AS TUESDAY.

.LONG TERM (THU-SUN)...
RATHER HIGH CONFIDENCE IN A DRY FORECAST FROM CHRISTMAS DAY THROUGH
THE HOLIDAY WEEKEND. A WEAK STORM SYSTEM CROSSES NORTHERN CA ON
THURSDAY BRINGING ADDITIONAL COOLING AND SOME HIGH CLOUDS INTO
SOUTHWEST CA. THE FRONT ASSOCIATED WITH THIS SYSTEM STALLS AND
PUSHES BACK TO THE NORTH LATE ON FRIDAY AND SATURDAY. ADDITIONAL
HIGH CLOUDS COULD MOVE OVER THE REGION AS THE FRONT LIFTS NORTHWARD
AND HIGH PRESSURE REBUILDS ACROSS THE EASTERN PACIFIC OCEAN DURING
THIS TIME FRAME. A FAIRLY AMPLIFIED TROUGH-RIDGE-TROUGH PATTERN IS
SHAPING UP ACROSS THE PACIFIC INTO THE WESTERN U.S. TO END THE YEAR.
THE GFS MODEL IS SHOWING A LOW PRESSURE SYSTEM MAKING AN ATTEMPT TO
UNDERCUT THE HIGH PRESSURE RIDGE TOWARD THE LAST DAY OF THE MONTH.

WE SHOULD SEE WEAK ONSHORE FLOW WITH COOLER TEMPERATURES THURSDAY
THROUGH SUNDAY BUT STILL AT OR ABOVE NORMAL FOR MOST AREAS.

&&

.AVIATION...21/0000Z...

AT 2330Z...THERE WAS A INVERSION BASED AT 2100 FEET WITH A TOP OF
5100 FEET AND A TEMP OF 16 CELSIUS.

OVERALL...MODERATE TO HIGH CONFIDENCE IN 00Z TAF PACKAGE. OVERALL
EXPECT NORTH TO NORTHEAST FLOW TO KEEP LOW CIGS OUT OF MOST
LOCATIONS...EXCEPT FOR KPRB WHERE VLIFR CONDS ARE EXPECTED FROM
10Z-18Z. THE TIMING THERE MAY DIFFER BY 2 HRS FROM TAF TIMES.
LLWS/TURBULENCE EXPECTED FOR KSBA AND KBUR DURING THE EVENING
HOURS...STRONGEST AT KSBA.

KLAX...HIGH CONFIDENCE IN 00Z TAF. MVFR VSBY MAY AFFECT THE AIRFIELD
AT TIMES THROUGH 20Z MONDAY.

KBUR...MODERATE TO HIGH CONFIDENCE IN 00Z TAF. HIGH CONFIDENCE IN
VFR CONDS. MODERATE CONFIDENCE IN WIND FORECAST WITH A 20% CHANCE
THAT LLWS WILL NOT OCCUR.

&&

.MARINE...21/130 PM...

FOR THE OUTER WATERS...HIGH CONFIDENCE IN CURRENT FORECAST.
NORTHWEST TO NORTH WINDS WILL INCREASE TO GALE FORCE THIS AFTERNOON
FROM POINT SAL DOWN TO SAN NICOLAS ISLAND...WITH SOLID SMALL CRAFT
LEVEL WINDS NORTH OF POINT SAL. THE GALE FORCE WINDS WILL CONTINUE
THROUGH MONDAY MORNING...BEFORE DIMINISHING SLOWLY TO SMALL CRAFT
LEVELS. BY TUESDAY/WEDNESDAY...WINDS ARE EXPECTED TO BE BELOW
ADVISORY LEVELS.

FOR THE INNER WATERS...MODERATE CONFIDENCE IN SMALL CRAFT ADVISORY
LEVEL WINDS THROUGH MONDAY MORNING FOR THE WESTERN HALF OF THE SANTA
BARBARA CHANNEL. ELSEWHERE...MODERATE TO HIGH CONFIDENCE IN WINDS
REMAINING BELOW SMALL CRAFT LEVELS THROUGH MONDAY EVENING. LATE
MONDAY NIGHT AND TUESDAY...MODERATE OFFSHORE FLOW IS EXPECTED AND
THERE IS MODERATE CONFIDENCE IN SMALL CRAFT ADVISORY LEVEL WINDS
FROM VENTURA SOUTH TO SANTA MONICA.

&&

.BEACHES...21/130 PM...

THE LARGE NORTHWEST SWELL CONTINUES TO SLOWLY DIMINISH THIS
AFTERNOON. FOR THE CENTRAL COAST...STILL EXPECT MARGINAL HIGH SURF
CONDITIONS THROUGH THIS EVENING...BUT NO COASTAL FLOODING ISSUES.
FOR AREAS SOUTH OF POINT CONCEPTION...WILL EXPECTED CONTINUED
ELEVATED SURF AND DANGEROUS RIP CURRENTS FOR THE WEST FACING BEACHES
OF VENTURA AND LOS ANGELES COUNTIES THROUGH THIS AFTERNOON.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
HIGH SURF ADVISORY (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&

$$

PUBLIC...BOLDT
AVIATION/MARINE...SMITH
SYNOPSIS...BOLDT

WWW.WEATHER.GOV/LOSANGELES








USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.