Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 071502
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
800 AM PDT TUE JUL 7 2015

.SYNOPSIS...

A COOLING TREND AND NIGHT THROUGH MORNING LOW CLOUDS AND FOG WILL
CONTINUE THROUGH THURSDAY AS LOW PRESSURE OFF THE COAST MOVES EAST.
THERE IS A SLIGHT CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS ON
WEDNESDAY AND THURSDAY. GRADUAL WARMING IS EXPECTED OVER THE WEEKEND
INTO EARLY NEXT WEEK...BUT TEMPERATURES WILL REMAIN NEAR OR SLIGHTLY
BELOW NORMAL WITH A BROAD TROUGH OF LOW PRESSURE IN PLACE.

&&

.SHORT TERM (TODAY-THU)... MARINE LAYER IS 1900 FEET DEEP AND CAPPED
BY A DECENT INVERSION. GRADIENTS ARE ONSHORE BUT TRENDING
OFFSHORE...ESP NORTH/SOUTH. THESE OFFSHORE TRENDS ARE DELAYING THE
ONSET OF LOW CLOUDS ACROSS A FEW AREAS (VENTURA AND SLO COUNTIES)
BUT THE STRATUS WILL FILL IN BY DAWN. THE SUNDOWNER CAME IN MUCH
WEAKER THAN FCST AND THE STRATUS WILL NOW BE ABLE TO PUSH INTO THE
SBA SOUTH COAST THIS MORNING. SLOWER THAN NORMAL CLEARING AGAIN AND
A FEW BEACHES WILL STAY CLOUDY ALL DAY. SLIGHT INSTABILITY THIS
AFTERNOON OVER THE MTNS BUT VERY LITTLE MOISTURE SO EXPECT SOME
AFTERNOON MTN BUILD UPS BUT NO SHOWERS. MAX TEMPS WILL BE VERY
SIMILAR TO MONDAY.

A UPPER LOW APPROACHES THE AREA WEDNESDAY. THE FALLING HGTS AND THE
WEAK LIFT ASSOC WITH THIS LOW WILL DEEPEN THE MARINE LAYER AND IT
WILL OVER THE COASTS AND MOST OF THE VLYS. THERE WILL LIKELY BE
ENOUGH LIFT TO CREATE SOME DRIZZLE AROUND DAWN. THERE IS STILL NOT
MUCH IN THE WAY OF MOISTURE BUT WITH THE EXTRA LIFT AND INSTABILITY
ASSOC WITH THE UPPER LOW THERE WILL BE A SLIGHT CHC OF AFTERNOON AND
EARLY EVENING TSTMS OVER THE MTNS...ESP THE VTA MTNS. MAX TEMPS WILL
BE A DEGREE OR TWO COOLER THAN TODAY DUE TO THE LOWER HGTS AND THE
DEEPER MARINE LAYER.

THURSDAY WILL BE VERY SIMILAR TO WEDNESDAY EXCEPT THAT THE UPPER LOW
WILL MOVE RIGHT OVER THE AREA AND IT WILL BE ACCOMPANIED BY A LOW
LEVEL JET. THE DAY WILL START OFF WITH ANOTHER ROBUST MARINE LAYER
AND SOME PATCHY DRIZZLE. AGAIN LOOK FOR SLOW CLEARING AND NO
CLEARING AT MANY BEACHES. BOY OF THERE WAS ANY MOISTURE THERE WOULD
LIKELY BE QUITE THE CONVECTIVE OUTBREAK IN THE AFTERNOON AND EVENING
AS THE UPPER LOW MOVES RIGHT OVERHEAD. STILL EVEN WITH VERY LIMITED
MOISTURE THERE WILL BE AT LEAST A SLIGHT CHC OF TSTMS OVER THE MTNS
IN THE AFTERNOON AND EARLY EVENING. WILL HAVE TO KEEP AN EYE ON THIS
AS POPS MAY NEED TO BE HIGHER. MAX TEMPS WILL COOL ANOTHER DEGREE OR
TWO AND THURSDAY WILL BE THE COOLEST DAY OF THE NEXT 7.

.LONG TERM (FRI-MON)... ALL MDLS ARE NOW IN AGREEMENT THAT A BROAD
TROF WILL COVER THE WEST COAST WHILE A LARGE UPPER HIGH WILL SIT
OVER TEXAS. THE FLOW ALOFT WILL BE FROM THE SW. THIS DRY FLOW
PATTERN WILL NOT ALLOW ANY MONSOON MOISTURE INTO THE AREA. ONSHORE
FLOW WILL CONTINUE THROUGH THE PERIOD AND THERE WILL BE PERSISTENT
NIGHT THROUGH MORNING LOW CLOUD PATTERN FOR THE COASTS AND VLYS
OTHERWISE SKIES WILL BE MOSTLY CLEAR. MAX TEMPS WILL SLOWLY RISE
THROUGH THE PERIOD AS HGTS REBOUND AND THE ONSHORE FLOW WEAKENS.

OF NOTE...THE GFS IS FORECASTING ACTUAL OFFSHORE FLOW NEXT WEDNESDAY
MORNING. OF COURSE NO GOOD EVER COMES FROM BELIEVING IN A DAY 8
FORECAST BUT IT IS INTERESTING TO CONSIDER.

&&

.AVIATION...

07/1045Z

AT 1030Z...THE MARINE INVERSION AT KLAX WAS BASED AT 2200 FEET. THE
TOP OF THE INVERSION WAS 3900 FEET WITH A TEMPERATURE OF 21 DEGREES
CELSIUS.

OVERALL...MODERATE CONFIDENCE WITH 12Z TAFS. HIGHER CONFIDENCE OVER
L.A. COUNTY. THERE IS A 30 PERCENT CHC THAT CSTL CIGS COULD SCATTER
OUT BETWEEN 20Z-24Z TODAY. HI CONFIDENCE THAT KPRB WILL STAY VFR
THROUGH TONIGHT...THAN 50 PERCENT CHANCE FOR IFR CIGS TUE MORNING
AFTER 11Z.

KLAX...GOOD CONFIDENCE IN TAF. THERE IS A 30% CHANCE CIGS COULD
SCATTER OUT 23Z-05Z.

KBUR...GOOD CONFIDENCE IN TAF. CIGS COULD ARRIVE +/- 1 HOUR OF FCST.
CIGS COULD DISSIPATE ANY TIME BETWEEN 18Z AND 20Z.

&&

.MARINE...07/315 AM...

FOR THE OUTER WATERS...MODERATE CONFIDENCE IN NORTHWEST WINDS
REMAINING AT SMALL CRAFT LEVELS THROUGH EARLY WEDNESDAY MORNING FROM
POINT SAL SOUTH. 30 PERCENT CHANCE THAT SMALL CRAFT ADVISORY WILL BE
NEEDED FOR ZONE 670 THIS AFTERNOON. THERE COULD BE LOCAL GUSTS TO 25
KNOTS BETWEEN PIEDRAS BLANCAS AND POINT SAL. FOR WEDNESDAY THROUGH
THE SECOND HALF OF THE WEEK...THERE WILL BE A 30% CHANCE OF
NORTHWEST GUSTS REACHING SMALL CRAFT LEVELS.

FOR THE INNER WATERS...HIGH CONFIDENCE IN WESTERLY WINDS REMAINING
BELOW SMALL CRAFT LEVELS THROUGH THE WEEK. THERE IS A 30% CHANCE
THIS AFTERNOON AND EVENING OF GUSTS TO 25 KT ACROSS THE WESTERN
PORTIONS OF THE INNER WATERS...ESPECIALLY THE WESTERN PART OF THE
SANTA BARBARA CHANNEL. LOWER CHANCES THE FOLLOWING FEW DAYS.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...RORKE
AVIATION/MARINE...KAPLAN
SYNOPSIS...SUKUP

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