Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 021201 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATES
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
440 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 AT LEAST FRIDAY. A FEW MORNING SPRINKLES
CANT BE RULED OUT SOUTH OF POINT CONCEPTION THIS MORNING. BELOW
NORMAL TEMPERATURES IN MOST AREAS 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
OF 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 IN MOST AREAS. 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...AND 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 IS SLIGHTLY MORE AGGRESSIVE IN DIGGING THE UPPER LOW INTO
NRN NEVADA...WHILE 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 IS THAT 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...02/1145Z.

AT 1107Z...THE MARINE LAYER AT KLAX WAS 3100 FT DEEP. THE TOP OF THE
INVERSION WAS AROUND 5100 FT WITH A TEMPERATURE OF 18 DEG CELSIUS.

WIDESPREAD MVFR CIGS IN ALL COASTAL AND VALLEY AREAS S OF PT
CONCEPTION...WITH IFR TO LIFR CIGS IN THE FOOTHILLS AND
COASTAL SLOPES. N OF PT CONCEPTION PATCHY LOW MVFR TO IFR
CIGS WERE AFFECTING THE CENTRAL COAST. ABOVE THE STRATUS
PLENTY OF MID AND HIGH CLOUDS WILL STREAM ACROSS THE REGION
THIS MORNING. THERE COULD BE A FEW SPRINKLES S OF PT CONCEPTION
THIS MORNING. EXPECT CLEARING OF THE STRATUS TO BE FAIRLY SLOW
TODAY. CIGS MAY LINGER IN SOME AREAS S OF PT CONCEPTION WELL
INTO THE AFTERNOON...ALTHOUGH THEY MAY RISE INTO THE VFR CATEGORY AS
WELL. EXPECT WIDESPREAD STRATUS AGAIN IN MOST COASTAL AREAS
TONIGHT/THU MORNING...WITH MOSTLY MVFR CONDS EXPECTED.

KLAX...MODERATE CONFIDENCE IN THE 12Z TAF. THERE IS A
20 TO 30 PERCENT CHANCE THAT CIGS COULD LINGER THROUGH
THE AFTERNOON.

KBUR...MODERATE CONFIDENCE IN THE 12Z TAF. THERE IS A
20 TO 30 PERCENT CHANCE THAT CIGS COULD LINGER THROUGH THE
AFTERNOON.

&&

.MARINE...02/400 AM.

FAIRLY HIGH CONFIDENCE THAT WINDS AND SEAS WILL REMAIN BELOW SCA
LEVELS ACROSS THE WATERS THROUGH THU...ALTHOUGH THERE WILL LIKELY BE
LOCAL SCA LEVEL GUSTS TO 25 KT ACROSS THE OUTER WATERS THIS
AFTERNOON AND EVENING. THERE IS A 20 PERCENT CHANCE THAT SCA
WILL BE NEEDED FOR THE NORTHERN OUTER WATERS THIS AFTERNOON INTO
TONIGHT AND AGAIN THU AFTERNOON INTO THE NIGHT. THERE IS A GOOD
CHANCE OF WIDESPREAD SCA WINDS ACROSS THE OUTER WATERS LATE
FRI OR FRI NIGHT THROUGH SAT NIGHT.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...KAPLAN
AVIATION/MARINE...DB

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