Area Forecast Discussion
Issued by NWS Los Angeles, CA

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511
FXUS66 KLOX 141830
AFDLOX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1030 AM PST SUN FEB 14 2016

.SYNOPSIS...
A BUILDING RIDGE ALOFT AND GUSTY OFFSHORE WINDS WILL BRING A RETURN
OF RECORD HEAT AND DRY CONDITIONS TODAY THROUGH TUESDAY. AN UPPER
LEVEL LOW WILL SUPPORT MUCH COOLER CONDITIONS WITH THE CHANCE OF
RAIN LATE WEDNESDAY INTO THURSDAY. FAIR SKIES WITH A SLIGHT WARM UP
IS EXPECTED BY NEXT WEEKEND.


&&

.SHORT TERM...(TDY-TUE)

LATEST VIS SAT IMAGERY INDICATED A VERY STUBBORN SHALLOW MARINE
LAYER OVER THE WEST AND SOUTHERN PORTION OF THE L.A. COASTAL ZONE.
LATEST AMDAR PROFILE DATA INDICATED THE MARINE LAYER AT 300 FT
WITH A TEMP AT THE BOTTOM OF THE INVERSION OF 51 DEGREES. THEN
WARMING TO 72 DEGREES AT 2700 FT. QUITE STRONG. THEREFORE THE
DENSE FOG ADVISORY HAS BEEN EXTENDED TO 10 AM THIS MORNING. THERE
STILL COULD BE PATCHY DENSE FOG ALONG THE COAST THROUGH THE
REMAINDER OF THE MORNING. OVERALL THE L.A. MARATHON RUNNERS HAVE
EXPEREIENCED COOL WEATHER THIS MORNING THANKS TO THE SHALLOW
MARINE LAYER...ESPECAILLY NEAR THE COAST. WHEN THE NORTHERLY WINDS
BREAKTHROUGH AND SCOUR OUT THE MARINE LAYER ACROSS WEST L.A. TEMPS
WILL INCREASE AND HUMIDITY WILL CRASH. SO RUNNERS WHO FINISH LATER
TODAY WILL LIKELY DEAL WITH MUCH WARMER CONDITIONS AND SOME BREEZY
CONDITIONS BELOW THE HOLLYWOOD HILLS AND SANTA MONICA MOUNTAINS.

MEANWHILE FOR AREAS TO THE NORTH...GUSTY NORTHERLY WINDS HAVE
DEVELOPED BEHIND A WEAK UPPER DISTURBANCE THAT MOVED THROUGH THE
AREA YESTERDAY. WIND ADVISORIES ARE IN EFFECT FOR THE SANTA
BARBARA COUNTY MOUNTAINS AND ADJACENT SOUTH COAST THROUGH NOON
TODAY WHERE WIND FAVORED PASSES AND CANYONS WERE EXPERIENCING
GUSTS TO 45 MPH INCLUDING REFUGIO AND THE HILLS ABOVE MONTECITO.
WIND ADVISORIES ARE ALSO IN EFFECT FOR THE L.A. AND VENTURA COUNTY
MTNS INCLUDING THE SANTA MONICA RANGE AS WELL AS THE VENTURA
COUNTY VALLEYS AND THE SANTA CLARITA AND SAN FERNANDO VALLEYS
THROUGH 3 PM MONDAY. NORTHERLY WINDS WILL BEGIN TO SHIFT OUT OF
THE NORTHEAST LATE THIS AFTERNOON AND EVENING BECOMING A MODERATE
SANTA ANA WIND EVENT WITH MORE WIDESPREAD WINDS ACROSS MUCH OF
VENTURA COUNTY. A WIND ADVISORY WILL START ACROSS THE VENTURA
COUNTY COAST LATER THIS EVENING.

FORECAST IS IN GOOD SHAPE OVER THE NEXT SEVERAL DAYS.

***FROM PREVIOUS DISCUSSION***

AREAS OF LOW CLOUDS AND DENSE FOG ASSOCIATED WITH A VERY SHALLOW
MARINE LAYER WERE HANGING ON TENACIOUSLY ACROSS THE LOS ANGELES
COUNTY COAST...DESPITE INCREASINGLY STRONG OFFSHORE GRADIENTS...
ESPECIALLY N-S GRADIENTS. THE GRADIENT BETWEEN KLAX AND KBFL WAS
NEARLY 7 MB OFFSHORE...AND EVEN THE KLAX TO KDAG GRADIENT WAS
ALMOST 3 MB OFFSHORE. GUSTY WINDS WERE AFFECTING THE MTNS OF
L.A...VTU AND SBA COUNTIES...THE SBA COUNTY SOUTH COAST...PORTIONS
OF THE SAN FERNANDO AND SANTA CLARITA VALLEYS...THE SANTA MONICA
MOUNTAINS...AND THE ERN VLYS OF VTU COUNTIES. WIND ADVISORIES ARE
IN EFFECT FOR THESE AREAS.

THE TRICKIEST PART OF FORECAST TODAY WILL UNFORTUNATELY BE THE
TEMPERATURE AND WIND FORECAST FOR THE LOS ANGELES BASIN THIS
MORNING. THE MARINE INVERSION WAS VERY STRONG...BUT AT SOME
POINT...THE OFFSHORE GRADIENTS WILL WIPE OUT THE INVERSION AND THE
CLOUDS. EXACTLY WHEN THAT HAPPENS WILL HAVE LARGE IMPLICATIONS FOR
THE PARTICIPANTS OF THE LOS ANGELES MARATHON. THROUGH ABOUT
DAYBREAK...EXPECT AREAS OF DENSE FOG TO CONTINUE...SO THE DENSE
FOG ADVISORY CONTINUES ACROSS THE L.A. COUNTY COAST. EXPECT THE
MARINE LAYER TO BEGIN TO BREAK APART AFTER DAYBREAK...AND SOME
GUSTY WINDS ARE EXPECTED TO SPREAD INTO LOCATIONS THROUGH AND
BELOW PASSES AND CANYONS FROM THE HOLLYWOOD HILLS TO MALIBU. THE
ARRIVAL OF THE NORTH WINDS WILL BE ACCOMPANIED BY A SHARP WARM
UP AND VERY LOW HUMIDITIES. ULTIMATELY...TEMPS SHOULD JUMP UP
TODAY ACROSS MOST OF THE L.A. COUNTY COAST...BUT EXACTLY WHEN THAT
WILL OCCUR IS STILL A BIT UNCERTAIN. THE BEST ESTIMATE IS BETWEEN
8 AM AND 11 AM. TEMPS SHOULD RISE INTO THE 80S...BUT MAY REMAIN
IN THE 70S RIGHT AT THE BEACHES.

AN UPPER RIDGE WILL AMPLIFY AND BUILD INTO CA TONIGHT AND MON.
LOW LEVEL FLOW WILL SHIFT TO A MORE NELY DIRECTION...AND
W-E OFFSHORE GRADIENTS WILL INCREASE. IN ADDITION...THERE WILL BE
SOME UPPER LEVEL SUPPORT IN THE FORM OF DECENT WINDS AT 850 MB AND
GOOD SUBSIDENCE. THIS SHOULD BRING WIDESPREAD ADVISORY LEVEL NE
WINDS TO VTU COUNTY AND MOST OF LOS ANGELES COUNTY TONIGHT AND
MON...WITH LOCAL HIGH WINDS WARNING GUSTS TO 60 TO 65 MPH
POSSIBLE IN THE WINDIER LOCATIONS IN THE MTNS AND FOOTHILLS. MAX
TEMPS SHOULD EDGE UPWARD A BIT MORE ON MON.

THE UPPER HIGH WILL BE AT ITS STRONGEST ACROSS THE REGION ON TUE
AND THICKNESSES WILL CONT TO RISE. GRADIENTS WILL REMAIN
OFFSHORE...LIKELY STRONG ENOUGH TO PRODUCE SOME GUSTY NE WINDS
ACROSS MUCH OF L.A. AND VTU COUNTIES...BUT WINDS WILL PROBABLY
REMAIN BELOW ADVISORY LEVELS. MAX TEMPS SHOULD RISE A BIT ON
TUE...WHICH SHOULD BE THE WARMEST DAY...ESPECIALLY IN THE VLYS.
MAX TEMPS COULD REACH OR SLIGHTLY EXCEED 90 DEGREES IN THE WARMEST
LOCATIONS IN THE VALLEYS AND INTERIOR SECTIONS OF THE COASTAL
PLAIN ON TUE.



.LONG TERM...(WED-SAT)

THE UPPER RIDGE WILL FLATTEN AND MOVE E TUE NIGHT AND WED AS A
TROUGH APPROACHES THE WEST COAST. LOW LEVEL GRADIENTS WILL TURN
ONSHORE. THERE WILL BE SIGNIFICANT COOLING ON WED...WITH MAX TEMPS
DOWN MORE THAN 10 DEGREES FROM THOSE ON TUE IN MANY AREAS. CLOUDS
WILL INCREASE...ESPECIALLY ACROSS SLO AND SBA COUNTIES...WHERE
THERE IS A SLIGHT CHANCE OF RAIN IN THE AFTERNOON. THE FRONTAL
SYSTEM WILL WEAKEN AS IT MOVES ACROSS THE REGION...BUT WILL
PROBABLY BRING SOME RAIN...MOSTLY ON THE LIGHT SIDE...TO MUCH OF
THE REGION WED NIGHT/THU. DRY WEATHER AND SEASONABLE TEMPS
ARE EXPECTED BEHIND THE SYSTEM ON FRI...WITH A WARMING TREND
EXPECTED OVER THE WEEKEND.


&&

.AVIATION...14/1800Z...AT KLAX...THE MARINE LAYER WAS 800 FEET DEEP. THE TOP
OF THE INVERSION WAS AT 1500 FEET WITH A TEMP OF 22C.

LOW TO MODERATE CONFIDENCE IN THE KLAX AND KLGB TAFS WHERE IFR
VSBY WILL GRADUALLY CLEAR EARLY THIS AFTERNOON. LOW CONFIDENCE IN
OVERNIGHT PERIOD AS CONDS FALL TO LIFR AGAIN. TIMING IS UNCERTAIN
AS IS THE LIKELIHOOD OF VSBY FALLING TO VLIFR.

HIGH CONFIDENCE ELSEWHERE AS OFFSHORE FLOW PATTERN CREATES GUSTY
N TO NE WINDS. N WINDS WILL CREATE OCNL LGT-MDT TURBC SFC-080
AND/OR LLWS THROUGH EARLY AFTERNOON IN THE VCNTY OF KSBA...KVNY
AND KBUR. TURBC AND LLWS WILL INCREASE IN COVERAGE AND INTENSITY
LATER THIS EVENING OVER AND NEAR TO HIER TRRN DUE TO NE WINDS.

KLAX...MODERATE CONFIDENCE IN THE 18Z TAF THROUGH 22Z DUE TO
TIMING OF VSBY TRANSITION TO VFR. LOW CONFIDENCE FOR OVERNIGHT
PERIOD AS CONDS FALL TO LIFR. THERE IS A 50% CHANCE OF VLIFR CONDS
AS VSBY MAY FALL TO OR BELOW 1/2SM.

KBUR...HIGH CONFIDENCE IN THE 18Z TAF. OCNL LGT-MDT TURBC AND/OR
LLWS THRU THE PD DUE TO GUSTY N TO NE WINDS.

&&

.MARINE...14/900 AM

FOR THE OUTER WATERS...HIGH CONFIDENCE IN FORECAST FOR BOTH SMALL
CRAFT ADVISORY (SCA) CONDITIONS FOR WINDS AND SEAS THIS MORNING
AND GALE FORCE WINDS THIS AFTERNOON AND EVENING. SCA CONDITIONS
WILL LIKELY CONTINUE AFTER THE GALE ENDS THROUGH EARLY MONDAY
MORNING.

FOR THE NEARSHORE WATERS N OF PT CONCEPTION...GOOD CONFIDENCE IN
SCA CONDITIONS THROUGH THE EVENING ASSOCIATED WITH THE LARGE AND
LONG PERIOD W-NW SWELL.

FOR THE NEARSHORE WATERS S OF PT CONCEPTION HIGH CONFIDENCE IN
SCA CONDITION DEVELOPING TONIGHT INTO MONDAY FOR GUSTY NORTHEAST
WINDS BELOW CANYONS MOUTHS. THE STRONGEST NORTHEAST WINDS ARE MOST
LIKELY BETWEEN VENTURA AND SANTA MONICA...BUT COULD ALSO IMPACT
THE SAN PEDRO CHANNEL AND AVALON HARBOR.


&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH SURF ADVISORY IN EFFECT UNTIL 5 PM PST THIS AFTERNOON
      FOR ZONES 34-35-40-41-87. (SEE LAXCFWLOX).
     WIND ADVISORY IN EFFECT UNTIL NOON PST TODAY FOR ZONES 39-52. (SEE LAXNPWLOX).
     BEACH HAZARDS STATEMENT IN EFFECT UNTIL NOON PST TODAY FOR
      ZONE 39. (SEE LAXCFWLOX).
     WIND ADVISORY IN EFFECT FROM 10 PM THIS EVENING TO 3 PM PST
      MONDAY FOR ZONE 40. (SEE LAXNPWLOX).
     WIND ADVISORY IN EFFECT UNTIL 3 PM PST MONDAY FOR ZONES
      44>46-53-54-547. (SEE LAXNPWLOX).
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS IN EFFECT UNTIL 9 PM
      PST THIS EVENING FOR ZONE 645. (SEE LAXMWWLOX).
     SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 PM PST THIS AFTERNOON
      FOR ZONES 670-673-676. (SEE LAXMWWLOX).

&&

$$

PUBLIC...KAPLAN/DB
AVIATION...SMITH
MARINE...SMITH
SYNOPSIS...SWEET

WEATHER.GOV/LOSANGELES



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