Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 021004
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
300 AM PDT WED SEP 2 2015

.SYNOPSIS...SCATTERED MID LEVEL CLOUDS WILL CONTINUE ACROSS AREAS
SOUTH OF POINT CONCEPTION THROUGH THIS MORNING ONSHORE FLOW WILL
SUPPORT MORNING CLOUDS WITH PATCHY FOG IN SOME AREAS TO THE WEST OF
THE MOUNTAINS THROUGH THE WEEKEND. A FEW MORNING SPRINKLES CANT BE
RULED OUT S OF POINT CONCEPTION THIS MORNING. BELOW NORMAL
TEMPERATURES THIS WEEK ARE EXPECTED TO REBOUND TO NEAR NORMAL BY
EARLY NEXT WEEK.

&&

.SHORT TERM (TODAY-FRI)...INTERESTING WEATHER PATTERN THIS MORNING.
A WEAK UPPER LOW WAS LOCATED 150 MILES WSW OF POINT CONCEPTION. THIS
RELATIVELY WEAK SYSTEM BROUGHT US PLENTY OF MID LEVEL CLOUDS OVER
MUCH OF THE FORECAST AREA OVERNIGHT AND WILL CONTINUE TO BRING MORE
MID LEVEL CLOUDS OVER THE AREA THIS MORNING THEN THIN OUT BY THE
AFTERNOON. BELOW THAT MID LEVEL CLOUD DECK WAS A PRETTY DEEP MARINE
LAYER WITH LOW CLOUDS REACHING THE COASTAL SLOPES THIS MORNING FOR
LA/VTU COUNTIES. THERE COULD BE A FEW SPRINKLES EARLY THIS MORNING
ACROSS PORTIONS OF LA/VTU/SBA COUNTIES DUE TO LIMITED LIFT AHEAD
WITH THE UPPER LOW. AS FAR AS TEMPS GO TODAY...EXPECT THE WARMEST
VALLEYS TO REACH THE MID 80S WHILE MOST COASTAL AREAS WILL RANGE
FROM THE HIGH 60S TO THE 70S. THE ANTELOPE VALLEY WILL REACH THE
UPPER 80S TODAY. OVERALL...HIGH TEMPS WILL REMAIN A FEW DEGREES
BELOW NORMAL FOR THIS TIME OF YEAR. THERE WILL BE BREEZY CONDITIONS
ACROSS THE HIGHWAY 14 CORRIDOR INTO THE ANTELOPE VALLEY AND ADJACENT
FOOTHILLS TODAY WITH LOCAL GUSTS AROUND 35 MPH THIS AFTERNOON AND
EVENING.

SYNOPTICALLY...AN UPPER LOW SITUATED OVER THE PAC NW OR VANCOUVER
CANADA WILL MOVE SOUTH OVER NRN CALIFORNIA BY FRIDAY. A BROAD UPPER
TROUGH ASSOCIATED WITH THIS UPPER LOW WILL LINGER OVER
CALIFORNIA...IN FACT WILL DEEPEN BY FRIDAY. AT THIS POINT IT LOOKS
LIKE THE MAIN EFFECT WILL BE A DEEP MARINE LAYER TO DEAL WITH.
EXPECT MODERATE ONSHORE WINDS TO CONTINUE ACROSS THE MOUNTAINS AND
ANTELOPE VALLEY THROUGH FRIDAY AS WELL. EXPECT LOW CLOUDS TO REACH
THE COASTAL SLOPES OVER THE NEXT FEW MORNINGS AS WELL...WITH LOW
CLOUDS SCOURING OUT TO THE COASTAL AREAS BY THE AFTERNOON. A FEW
BEACH CITIES MIGHT DEAL WITH LINGERING LOW CLOUDS INTO MID AFTERNOON
HOURS THROUGH FRIDAY.

.LONG TERM (SAT-TUE)... THE GFS AND ECMWF ARE IN A SLIGHT
DISAGREEMENT WITH THE PLACEMENT OF THE UPPER LOW ON SATURDAY. THE
GFS IN MORE PROGRESSIVE AS THE UPPER LOW DIGS INTO NRN NEVADA. THE
EC MODEL SHOWS THE LOW FILLING IN AS IT PULLS NE INTO IDAHO. THE GFS
500 MB ENSEMBLE SEEMS TO BE A BIT INCONSISTENT FROM SATURDAY ON. SO
FIGURING THE UPPER LOW WILL BE A TAD FARTHER NE ON SATURDAY. STILL
ADJUSTED HIGH TEMPS DOWN A COUPLE DEGREES. ONE NOTABLE ISSUE. ON
SUNDAY MORNING...THE GFS IS INDICATING A DECENT SURFACE OFFSHORE
GRADIENT. IF THIS HOLDS TRUE...THERE WILL BE SIGNIFICANT WARMING
ACROSS THE REGION...ESPECIALLY THE VALLEYS WITH SOME WARMING TO THE
COAST AS WELL. LOW CLOUDS SHOULD BE LIMITED N OF POINT CONCEPTION
WITH ONLY PATCHY LOW CLOUDS FOR THE CENTRAL COAST. TRICKY FORECAST
FOR STRATUS FOR THE LA/VTU COAST AND VALLEY SAT NIGHT INTO SUNDAY
DUE TO THE OFFSHORE TRENDS. FOR MON-TUE...BOTH MODELS ARE OUT OF
SYNC AS THE GFS SHOWS A WEAK UPPER LOW OFF THE CENTRAL CALIF COAST
WHILE THE EC BRINGS IN A WEAK UPPER RIDGE. FOR NOW...HAVE KEPT WHAT
EARLIER SHIFTS HAD. A SLIGHT WARMING TREND THROUGH EARLY NEXT WEEK.



&&

.AVIATION...02/0010Z.

AT 2308Z...THE MARINE INVERSION AT KLAX WAS AROUND 2000 FT DEEP. THE
TOP OF THE INVERSION WAS AROUND 3500 FEET WITH A TEMPERATURE OF 22
DEGREES CELSIUS.

GENERALLY HI CONFIDENCE IN THE 00Z TAFS WITH REGARD TO LOW CLOUD AND
IFR/MVFR DEVELOPMENT TONIGHT AT ALL COASTAL AND VLY AIRFIELDS WHICH
WILL PERSIST INTO LATE WED MORNING TO EARLY WED AFTERNOON...EXCEPT
AT KOXR WHERE THERE IS A 50-60 PERCENT CHANCE OF THE LOW CLOUDS
LASTING ALL DAY. THERE IS MODERATE CONFIDENCE IN THE TIMING OF THE
ONSET OF THE LOW CLOUDS WHICH COULD BE OFF PLUS/MINUS AN HOUR OR
TWO. FOR KWJF AND KPMD...HI CONFIDENCE IN THE 00Z TAFS WITH VFR
CONDITIONS EXPECTED THRU WED. GUSTY W TO SW WINDS AT THESE AIRFIELDS
THIS EVENING WILL DIMINISH TONIGHT AND INCREASE AGAIN WED AFTERNOON.

KLAX...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR
CIGS ARE FORECAST TO DEVELOP BY 08Z AND PERSIST THRU 20Z WITH VFR
CIGS THRU 03Z WED EVENING BEFORE THE CIGS LOWER AGAIN TO MVFR CAT.
THE TIMING OF THE ONSET OF THE LOW CLOUDS TONIGHT COULD BE OFF
PLUS/MINUS AN HOUR OR TWO.

KBUR...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND MVFR
CIGS ARE FORECAST TO DEVELOP BY 06Z AND PERSIST THRU 17Z WITH VFR
CONDITIONS THE REST OF THE DAY. THE TIMING OF THE ONSET OF THE LOW
CLOUDS TONIGHT COULD BE OFF PLUS/MINUS AN HOUR OR TWO.

&&

.MARINE...01/900 PM.

OUTER WATERS...LOCALLY MODERATE NORTHWEST WINDS CONTINUE TO AFFECT
PORTIONS OF THE OUTER WATERS THIS EVENING...BUT NOT WIDESPREAD
ENOUGH TO KEEP A SMALL CRAFT ADVISORY GOING SO IT HAS BEEN ALLOWED
TO EXPIRE. HOWEVER...LOCAL GUSTS TO 25 KNOTS MAY OCCUR DURING THE
OVERNIGHT PERIOD AND SHORT PERIOD WIND CHOP WILL CONTINUE IN SOME
AREAS. WINDS ARE EXPECTED TO BE NEAR BUT BELOW SCA THRESHOLDS
THROUGH THURSDAY...THEN INCREASING TO SCA LEVEL THURSDAY NIGHT AND
PERSISTING THROUGH THE WEEKEND. MODERATE CONFIDENCE IN THIS
FORECAST. MAINLY LIGHT WINDS ARE EXPECTED OVER THE NEAR-SHORE WATERS
THROUGH LATE IN THE WEEK...EXCEPT FOR THE WATERS NORTH OF POINT SAL
WHERE GUSTS UP TO 20 KNOTS WITH LOCAL GUSTS TO 25 KNOTS ARE EXPECTED
EACH AFTERNOON AND EVENING PERIOD THROUGH FRIDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...KAPLAN
AVIATION/MARINE...SIRARD

WWW.WEATHER.GOV/LOSANGELES


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