Area Forecast Discussion
Issued by NWS Los Angeles, CA

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370
FXUS66 KLOX 130622
AFDLOX

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1022 PM PST FRI FEB 12 2016

.SYNOPSIS...

A WEAK UPPER LEVEL TROUGH PASSING TO THE NORTH WILL PROVIDE A BRIEF
BREAK FROM THE RECORD HEAT THIS WEEKEND. A BUILDING RIDGE ALOFT
AND GUSTY OFFSHORE WINDS BRING A RETURN OF RECORD HEAT EARLY NEXT
WEEK. A SECOND UPPER LEVEL LOW WILL SUPPORT MUCH COOLER CONDITIONS
WITH THE CHANCE OF RAIN LATE WEDNESDAY INTO THURSDAY.

&&

.SHORT TERM...(FRI-MON)

UPPER LEVEL TROUGH MOVING INTO NORTHERN CALIFORNIA TONIGHT WITH
RIDGE AXIS SLIDING WELL EAST OF OUR AREA. THIS HAS RESULTED IN
SLIGHT ONSHORE TRENDS THIS EVENING...WITH CURRENT LAX-DAGGETT
GRADIENT AT -1.9 MB. SATELLITE IMAGERY SHOWING AREAS OF LOW
CLOUDS AND DENSE FOG ACROSS PORTIONS OF THE COASTAL WATERS
(WHICH WAS HIGHLIGHTED WITH A MARINE WEATHER STATEMENT)...LOCALLY
EXTENDING INTO THE CENTRAL COAST THIS EVENING. MOST OF THE FOG
OFFSHORE OF LOS ANGELES COUNTY IS FORMING NEAR CATALINA ISLAND
AND THE SAN PEDRO CHANNEL. BUT CONDITIONS ARE COMING TOGETHER FOR
SOME PATCHY DENSE FOG JUST ABOUT ANYWHERE ALONG THE IMMEDIATE
COAST TONIGHT...AND HAVE INCLUDED THAT IN ZONE UPDATE. COMBINATION
OF SHALLOW/STRONG MARINE INVERSION...WEAKENING PRESSURE
GRADIENTS...AND COASTAL DEWPOINTS RISING INTO THE MID 50S IS
REASONING FOR POTENTIAL DENSE FOG ALONG IMMEDIATE COAST.

AS THE TROUGH MOVES INLAND ON SATURDAY...THERE IS SOME INCREASING
NORTHERLY FLOW SETTING UP ACROSS THE FORECAST AREA...ESPECIALLY
TOMORROW NIGHT. INLAND AREAS NOT SHOWING A WHOLE LOT OF COOLING
ON SATURDAY AT 950 MB LEVEL...SO BUMPED UP MOST VALLEY
TEMPERATURES A FEW DEGREES IN EVENING UPDATE. TAKING A GLANCE
AT THE 00Z NAM MODEL...SEEING ANOTHER RESURGENCE OF OFFSHORE
FLOW FROM SUNDAY THROUGH TUESDAY WITH UPPER LEVEL RIDGE REBUILDING
OVER THE AREA. STILL LOOKING LIKE STRONGEST OFFSHORE WIND PUSH
WILL BE SUNDAY NIGHT INTO MONDAY WITH WIDESPREAD ADVISORIES
LIKELY ACROSS VENTURA AND LOS ANGELES COUNTIES. WITH PROJECTED
LAX-DAGGETT GRADIENT APPROACHING -7 MB ON SUNDAY MORNING AND
SOME UPPER LEVEL WIND/THERMAL SUPPORT...COULD SEE SOME ISOLATED
WIND GUSTS UP TO 60 MPH IN THE FAVORED MOUNTAIN AREAS. THE
OFFSHORE WINDS WITH LOW HUMIDITIES AND WARM TEMPERATURES WILL
BRING ANOTHER ROUND OF ELEVATED FIRE DANGER SUNDAY THROUGH
TUESDAY. THE OTHER BIG STORY WILL CONTINUE TO BE THE UNUSUALLY
HOT TEMPERATURES EXPECTED SUNDAY THROUGH TUESDAY...WITH MANY
COASTAL/VALLEY AREAS EXPECTED TO CLIMB WELL INTO THE 80S AND LOWER
90S. ON SUNDAY...COULD SEE A COUPLE OF RECORDS BROKEN THEN
EVEN BETTER CHANCE OF RECORDS BEING SET ON MONDAY AND TUESDAY.

.LONG TERM...(TUE-FRI)

FOR THE EXTENDED...12Z MODELS START OUT IN DECENT SYNOPTIC
AGREEMENT...BUT DIVERGE LATER IN THE PERIOD. AT UPPER LEVELS
RIDGE WILL LINGER ON TUESDAY THEN A TROUGH WILL APPROACH AND MOVES
ACROSS THE WEST COAST WEDNESDAY THROUGH FRIDAY. NEAR THE SURFACE
WEAK OFFSHORE FLOW WILL PREVAIL ON TUESDAY THEN SHIFT TO ONSHORE
WEDNESDAY THROUGH FRIDAY.

FORECAST-WISE...TUESDAY WILL BE AN UNREMARKABLE DAY WITH CLEAR
SKIES...LIGHT OFFSHORE BREEZES AND HIGH TEMPERATURES WELL ABOVE
NORMAL. FOR WEDNESDAY AND THURSDAY...THE MODELS DIVERGE NOTICEABLY
LEADING TO A LOW CONFIDENCE FORECAST. THE ECMWF MOVES A TROUGH
ACROSS THE AREA WEDNESDAY/THURSDAY AND GENERATES A DECENT RAIN
EVENT FOR THE AREA. CONVERSELY...THE GFS IS MUCH LESS BULLISH WITH
THIS TROUGH...HARDLY SPITTING OUT ANY PRECIPITATION. WITH SUCH
MODELS DIFFERENCES...WILL NOT DEVIATE FROM PREVIOUS FORECAST
THINKING WHICH INCLUDED CHANCE/SLIGHT CHANCE POPS FOR THE AREA
WEDNESDAY AND THURSDAY. HOPEFULLY...MODELS WILL COME INTO SOME
BETTER AGREEMENT OVER THE NEXT COUPLE OF DAYS. BY THURSDAY NIGHT
AND FRIDAY...BOTH MODELS PUSH TROUGH EAST OF THE AREA AND INDICATE
DRY CONDITIONS.

&&

.AVIATION...13/0600Z.

AT 0530Z...AT KLAX...THERE WAS A SURFACE BASED INVERSION LAYER TO
1700 FEET WITH A TEMP OF 24 DEG C.

FOR COASTAL TAF SITES INCLUDING KSMX & KPRB...LOW CONFIDENCE IN
THE 06Z TAFS THROUGH 16Z DUE THE POSSIBILITY OF FOG/LOW CLOUDS.
EXPECT IFR TO LIFR WITH LOCALIZED VLIFR IN AREAS WHERE FOG/LOW
CLOUDS DO DEVELOP. MODERATE TO HIGH CONFIDENCE FOR THE REMAINDER
OF THE TAF PERIOD.

INLAND TAF SITES...HIGH CONFIDENCE IN 06Z CAVU TAFS.

KLAX...LOW CONFIDENCE IN 06Z TAF THROUGH 16Z DUE TO THE
POSSIBILITY OF LOW FOG AND LOW CLOUDS. THERE IS A 40 PERCENT
CHANCE OF LIFR TO VLIFR CIGS/VSBYS DUE TO FOG/LOW CLOUDS THROUGH
16Z. MODERATE CONFIDENCE IN THE REMAINDER OF THE TAF PERIOD.

KBUR...HIGH CONFIDENCE IN 06Z CAVU TAF.

&&

.MARINE...12/800 PM...

A MARINE WEATHER STATEMENT WAS ISSUED THIS EVENING FOR THE
POSSIBILITY OF DENSE FOG FOR ALL AREAS THROUGH SATURDAY MORNING.
PLEASE SEE MWSLOX FOR DETAILS.

FOR THE OUTER WATERS...THERE IS HIGH CONFIDENCE IN SMALL CRAFT
ADVISORY (SCA) CONDITIONS THROUGH LATE SUNDAY NIGHT DUE TO EITHER
SCA WINDS OR A 10-13 FT...LONG PERIOD W-NW SWELL. THE STRONGEST
N-NW WINDS ACROSS THE OUTER WATERS ARE EXPECTED SATURDAY AFTERNOON
AND NIGHT...WHEN THERE COULD BE SOME LOCAL GALE FORCE WINDS. SCA
WINDS COULD LINGER INTO MONDAY...BUT SHOULD WEAKEN CONSIDERABLY BY
TUESDAY.

FOR THE INNER WATERS N OF PT CONCEPTION...THERE IS HIGH
CONFIDENCE IN SCA CONDITIONS FOR HAZARDOUS SEAS THROUGH SUNDAY
EVENING. THIS IS DUE TO THE 10-13 FT...LONG PERIOD W-NW SWELL.
WINDS WILL GENERALLY REMAIN BELOW SCA CRITERIA...THROUGH THE
FORECAST PERIOD...BUT THERE COULD BE SOME LOCAL N-NE GUSTS TO 25
KT SATURDAY EVENING THROUGH MONDAY EVENING.

FOR THE INNER WATERS S OF PT CONCEPTION...THERE IS GOOD CONFIDENCE
THAT WINDS AND SEAS WILL REMAIN BELOW SCA CRITERIA THROUGH SUNDAY
AFTERNOON. HOWEVER...SOME 10 FT SEAS ARE POSSIBLE IN WESTERN
PORTIONS OF THE SANTA BARBARA CHANNEL THROUGH SATURDAY
AFTERNOON...DUE TO THE LONG PERIOD SWELL. THERE IS ALSO A CHANCE
FOR SOME ISOLATED NE WIND GUSTS TO 25 KT ON SUNDAY MORNING BETWEEN
SANTA MONICA AND VENTURA. STRONGER NE WINDS ARE EXPECTED LATE
SUNDAY NIGHT INTO MONDAY...WHEN A SCA MAY BE NEEDED.


&&

.LOX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH SURF ADVISORY IN EFFECT UNTIL 9 AM PST SUNDAY FOR ZONES
      34-35. (SEE LAXCFWLOX).
     BEACH HAZARDS STATEMENT IN EFFECT THROUGH SUNDAY MORNING FOR
      ZONE 39. (SEE LAXCFWLOX).
     HIGH SURF ADVISORY IN EFFECT UNTIL NOON PST SUNDAY FOR ZONES
      40-41-87. (SEE LAXCFWLOX).
PZ...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS IN EFFECT UNTIL 9 PM
      PST SUNDAY FOR ZONE 645. (SEE LAXMWWLOX).
     SMALL CRAFT ADVISORY IN EFFECT UNTIL 3 AM PST MONDAY FOR
      ZONES 670-673-676. (SEE LAXMWWLOX).

&&

$$

PUBLIC...GOMBERG
AVIATION...MUNROE/DB
MARINE...SUKUP
SYNOPSIS...MUNROE

WEATHER.GOV/LOSANGELES



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