Area Forecast Discussion
Issued by NWS Los Angeles, CA

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000
FXUS66 KLOX 311754
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1040 AM PDT THU JUL 31 2014

.SYNOPSIS...
AN UPPER LEVEL HIGH JUST TO THE EAST OF THE REGION WILL KEEP
TEMPERATURES GENERALLY ABOVE NORMAL THROUGH THE WEEKEND...WITH NIGHT
THROUGH MORNING LOW CLOUDS CONFINED MOSTLY TO COASTAL SECTIONS. SOME
MONSOONAL MOISTURE MAY CREEP INTO THE REGION BY SUNDAY...BRINGING A
SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS TO THE
MOUNTAINS AND DESERTS. SLIGHT COOLING IS POSSIBLE EARLY NEXT WEEK AS
THE UPPER HIGH WEAKENS A BIT.

&&

.SHORT TERM (TODAY-SAT)...NKX AND VBG SOUNDINGS SHOW COOLING IN THE
LOWEST 2000` BUT WARMING ABOVE THAT, INDICATING A STRENGTHENING OF
THE MARINE INVERSION. HOWEVER, GRADIENTS ARE TRENDING OFFSHORE BY
ABOUT 1 MB. TEMP TRENDS THIS MORNING ARE MIXED BUT MOSTLY RUNNING A
COUPLE DEGREES COOLER AT LOWER ELEVATIONS AND WARMER IN THE MTNS,
MIRRORING THE TRENDS IN THE SOUNDINGS. OVERALL, MINIMAL CHANGES IN
HIGHS TODAY, GENERALLY +/- 2 DEGREES FROM YESTERDAY. CONSIDERING THE
LACK OF THUNDERSTORM ACTIVITY YESTERDAY IN OUR AREA IT SEEMS
UNLIKELY WE`LL SEE ANY TODAY GIVEN THAT THE MOISTURE IS LESS. STILL
COULD SEE SOME AFTERNOON BUILDUPS THOUGH. EXPECTING A SIMILAR ROUND
OF SUB-ADVISORY LEVEL NORTHERLY WINDS IN THE SBA AREA AGAIN THIS
EVENING.

***FROM PREVIOUS DISCUSSION***

THE UPPER PATTERN WILL CHANGE LITTLE THROUGH SAT...WITH AN UPPER
HIGH TO THE EAST OF THE REGION...AND A RIDGE EXTENDING ACROSS THE
FORECAST AREA. THIS SHOULD KEEP ANY MONSOONAL FLOW OUT OF THE REGION
THROUGH SAT. THE WRF SHOWS WEAK EDDY CIRCULATIONS EACH OF THE NEXT
COUPLE OF NIGHTS...WITH AREAS OF LOW CLOUDS AND FOG ACROSS COASTAL
SECTIONS OF L.A. COUNTY...POSSIBLY REACHING AS FAR NORTH AS THE VTU
COUNTY COAST. IT ALSO SHOWS CLEAR SKIES N OF PT CONCEPTION...BUT
THERE SEEMS TO BE NO REAL REASON FOR THIS...SO WILL LEAVE NIGHT
THROUGH MORNING LOW CLOUDS IN THE FCST ON THE CENTRAL COAST AND IN
THE SANTA YNEZ VALLEY. DO NOT EXPECT MUCH CHANGE IN MAX TEMPS ON
FRI...ALTHOUGH IF THE EDDY CIRCULATION IS STRONG ENOUGH...THERE MAY
BE SOME COOLING IN COASTAL AND POSSIBLY VLY AREAS S OF PT
CONCEPTION. HEIGHTS WILL FALL SLIGHTLY ON SAT AS THE UPPER HIGH TO
THE EAST BEGINS TO WEAKEN...SO THERE COULD BE A COUPLE OF DEGREES OF
COOLING IN MOST AREAS...BUT TEMPS WILL STILL BE AT LEAST SLIGHTLY
ABOVE NORMAL IN MOST AREAS.

.LONG TERM (SUN-WED)...A WEAK UPPER LOW IS FORECAST TO DRIFT
NORTHWESTWARD FROM MEXICO ON SUNDAY. IT MAY CAUSE SOME MONSOONAL
MOISTURE TO PUSH INTO THE REGION...SO THE SLIGHT CHANCE OF TSTMS IN
THE MTNS AND ANTELOPE VALLEY LOOKS GOOD. HOWEVER...A WEAK TROUGH
WILL APCH NRN CA...POSSIBLY CAUSING THE MID AND UPPER FLOW TO
BECOME DRIER SWLY...AND THERE IS A FAIR CHANCE THAT THE BEST
ACTIVITY WILL REMAIN EAST OF THE REGION. THAT WEAK TROUGH MAY BRING
A BIT OF COOLING TO THE REGION FOR EARLY NEXT WEEK...BUT CONFIDENCE
IN THAT IS JUST LOW TO MODERATE AND WILL BE DETERMINED BY HOW
STRONGLY THE UPPER HIGH TO THE EAST MAINTAINS ITS GRIP ON THE REGION.


&&

.AVIATION...31/18Z...

MODERATE CONFIDENCE IN 18Z TAFS WITH THE REDUCED CONFIDENCE DUE TO
THE UNCERTAINTY REGARDING THE MARINE LAYER LOCATION... INTENSITY...
AND DURATION.  A NINETY PERCENT CHANCE OF THE MARINE LAYER
RETURNING TO THE CENTRAL COAST INCLUDING DENSE FOG AT KSMX... EIGHTY
PERCENT THAT IT RETURNS TO OXNARD... AND WITH AN EDDY DEVELOPING
THERE IS A SIXTY PERCENT CHANCE OF IFR CONDITIONS AT KLAX AND KLGB
OVERNIGHT AND EARLY TOMORROW MORNING.  CONDITIONS SHOULD CLEAR BY
17Z IN LOCATIONS OTHER THAN KSMX.  OTHERWISE AND ELSEWHERE VFR
CONDITIONS WILL PREVAIL.

KLAX...MODERATE CONFIDENCE IN 18Z TAF. A SIXTY PERCENT CHANCE OF
IFR CIGS 09Z-17Z... OTHERWISE VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE FORECAST PERIOD.

KBUR...MODERATE TO HIGH CONFIDENCE IN 18Z TAF. A TEN PERCENT CHANCE
OF MVFR CONDITIONS 13Z-16Z... OTHERWISE VFR CONDITIONS WILL PREVAIL
THROUGHOUT THE FORECAST PERIOD.

&&

.MARINE...31/900 AM PDT

MODERATE CONFIDENCE IN CONTINUANCE OF SMALL CRAFT CONDITIONS ACROSS
THE SOUTHERN OUTER WATERS (PZZ673-676) THROUGH LATE TONIGHT.
OTHERWISE AND ELSEWHERE... CONDITIONS TO REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS THROUGH THE FORECAST PERIOD.

&&

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

&&
$$

PUBLIC...MW/DB
AVIATION...KJ
MARINE...KJ

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