Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 251856
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER...UPDATED
SERVICE LOS ANGELES/OXNARD CA
1155 AM PDT MON MAY 25 2015

...UPDATED SHORT TERM DISCUSSION FOR REMINDER OF TODAY...

.SYNOPSIS... PERSISTENT LOW PRESSURE OVER THE WESTERN UNITED STATES
WILL MAINTAIN BELOW NORMAL TEMPERATURES THROUGH MID WEEK WITH AMPLE
NIGHT THROUGH MORNING CLOUDS. HIGH PRESSURE WILL BUILD OVER
CALIFORNIA THURSDAY THROUGH THE WEEKEND BRINGING A WARMING TREND
AWAY FROM THE COAST. COASTAL AREAS SHOULD CONTINUE TO SEE LOW CLOUDS
AND FOG...AND HIGH TEMPERATURES WHICH WILL EDGE UP A BIT.

&&

.SHORT TERM (TODAY-WED)...

***UPDATED FOR REMINDER OF TODAY FORECAST***

MADE LATE MORNING UPDATE TO FORECAST FOR REMAINDER OF TODAY AS SATELLITE
TRENDS SHOWING INCREASED STRATOCUMULUS CLOUD DEVELOPMENT FOR AREAS SOUTH
OF POINT CONCEPTION. LATEST PILOT REPORTS SHOWING CLOUD TOPS UP TO 4000
FEET ACROSS LA BASIN. HAVE INCREASED CLOUD COVERAGE FOR REMAINDER OF TODAY
(WITH PARTLY TO MOSTLY CLOUDY CONDITIONS) AND TRIMMED BACK TEMPS
A FEW DEGREES FOR MANY AREAS SOUTH OF POINT CONCEPTION. IN ADDITION...EXPECTING
SOME CLOUD BUILDUPS OVER THE LOCAL MOUNTAINS TODAY DUE TO SOME RESIDUAL MOISTURE
AND INSTABILITY ASSOCIATED WITH DAYTIME HEATING.

***FROM PREVIOUS DISCUSSION***

WEAK UPPER LEVEL TROUGH OF LOW PRESSURE ACROSS NORTHERN AND CENTRAL
CALIFORNIA WILL CONTINUE TO BRING FAIRLY STRONG ONSHORE FLOW ACROSS
SOUTHERN CALIFORNIA. DEEP MARINE LAYER IN PLACE...WITH 12Z VANDENBERG
SOUNDING SHOWING DEPTH OF AROUND 3200 FEET...AND LATEST ACARS
SOUNDING SHOWING DEPTH AROUND 3000 FEET ACROSS THE LA BASIN. LOW
CLOUDS AND FOG ADVANCED INTO SOME OF THE LOWER COASTAL SLOPES OF THE
SAN GABRIELS THIS MORNING...BUT IS STARTING TO RETREAT NOW. MARINE
INVERSION REMAINS FAIRLY WEAK SO EXPECTING BURNOFF OF LOW CLOUDSTHIS
AFTERNOON ACROSS MANY AREAS. HOWEVER...DAYTIME HEATING WILL INTERACT
WITH LOW LEVEL MOISTURE TO GENERATE SOME STRATOCUMULUS CLOUDS...MOST
NUMEROUS ACROSS THE LA BASIN AND CENTRAL COAST. INLAND AREAS MAY SEE
A COUPLE DEGREES OF WARMING OTHERWISE LITTLE CHANGE IN TEMPERATURES
TODAY. THE EXCEPTION MAY BE ACROSS THE SALINAS VALLEY...AS A DECENT
SLY PUSH MAY CAUSE A BIT OF COOLING. OTHERWISE...WILL LIKELY HAVE TO
ADD SOME HIGHER LEVEL CLOUDS TO THE FORECAST FOR TONIGHT...WITH
INCREASING UPPER LEVEL MOISTURE AHEAD OF NEXT WEAK LOW IN THE EASTERN
PACIFIC.

*** FROM PREVIOUS DISCUSSION ***

AN UPPER LOW WILL MOVE INTO THE PAC NW TONIGHT AND TUE...AND A WEAK
TROUGH WILL APPROACH THE FORECAST AREA FROM THE WEST. THE WRF
INDICATED MORE IN THE WAY OF LOW LEVEL MOISTURE INTO ALL COASTAL AND
VALLEY AREAS TONIGHT...WITH WOULD SUGGEST NIGHT THROUGH MORNING
STRATUS ALL THE WAY INTO THE SANTA CLARITA VALLEY. THE UPPER
PATTERN...WITH THE APCHG TROUGH...IS FAVORABLE FOR A RATHER DEEP
MARINE LAYER AND EXTENSIVE STRATUS W OF THE MTNS. CONFIDENCE IS
STILL BELOW NORMAL THANKS TO THE CONTD WEAK INVERSION. MAX TEMPS ON
TUE SHOULD BE ABOUT THE SAME AS THOSE OF TODAY.

THE UPPER LOW OVER THE PAC NW WILL DRIFT INTO THE NORTHERN ROCKIES
TUE NIGHT AND WED...WHILE THE WEAK UPPER TROUGH WEST OF THE REGION
WILL MOVE ACROSS THE FCST AREA TUE NIGHT AND EARLY WED. DO NOT
EXPECT TOO MUCH CHANGE IN THE NIGHT THRU MORNING STRATUS PATTERN TUE
NIGHT/WED. MAX TEMPS SHOULD JUMP A FEW DEGREES...ESPECIALLY IN THE
MTNS AND DESERTS ON WED AS HEIGHTS RISE.

.LONG TERM (THU-SUN)...AN UPPER RIDGE WILL AMPLIFY IN THE ERN
PACIFIC THU...THEN THE RIDGE WILL EDGE INTO THE WEST COAST ON FRI.
THE MARINE LAYER WILL SHRINK IN DEPTH...AND THERE WILL BE A
REDUCTION IN NIGHT/MORNING LOW CLOUDS...ESPECIALLY IN THE VLYS. MAX
TEMPS WILL BE UP A FEW DEGREES BOTH THU AND FRI...WITH TEMPS ABOVE
NORMAL IN MOST AREAS ON FRI. THE RIDGE AXIS WILL MOVE E OF THE
REGION OVER THE WEEKEND...BUT HEIGHTS WILL REMAIN RATHER HIGH. DO
NOT EXPECT MUCH CHANGE IN MAX TEMPS ON SAT...THEN THERE COULD BE
SLIGHT COOLING...ESPECIALLY W OF THE MTNS ON SUNDAY.

&&

.AVIATION... 25/18Z

AT 17Z AT KLAX... THE INVERSION WAS 1550 FEET DEEP.  THE TOP OF THE
INVERSION WAS AT 4900 FEET WITH A TEMPERATURE OF 13 DEGREES CELSIUS.

OVERALL... MODERATE CONFIDENCE IN THE 18Z TAFS.  THE MARINE
INTRUSION WILL CONTINUE ALONG PORTIONS OF THE COAST AND WELL INTO
ADJACENT VALLEYS THROUGH MIDDAY.  IT WILL DIMINISH TO JUST OFF THE
COAST THIS AFTERNOON THOUGH THE TAF TIMING MAY BE OFF BY AN HOUR OR
SO.  THE INTRUSION WILL RETURN THIS EVENING AND WILL DEVELOP SIMILAR
TO LAST NIGHT AND THIS MORNING.  OTHERWISE AND ELSEWHERE VFR
CONDITIONS WILL PREVAIL.

KLAX... MODERATE CONFIDENCE IN THE 18Z TAF.  THE MARINE INTRUSION
WILL CONTINUE THROUGH MIDDAY THEN DIMINISH TO JUST OFF THE COAST
THIS AFTERNOON THOUGH THE TAF TIMING MAY BE OFF BY AN HOUR OR SO.
THE INTRUSION WILL RETURN THIS EVENING AND WILL DEVELOP SIMILAR TO
LAST NIGHT AND THIS MORNING.  OTHERWISE VFR CONDITIONS WILL PREVAIL.

KBUR... MODERATE CONFIDENCE IN THE 18Z TAF.  THE MARINE INTRUSION
WILL CONTINUE THROUGH MIDDAY THEN DIMINISH THIS AFTERNOON THOUGH THE
TAF TIMING MAY BE OFF BY AN HOUR OR SO.  THE INTRUSION WILL RETURN
THIS EVENING AND WILL DEVELOP SIMILAR TO LAST NIGHT AND THIS
MORNING.  OTHERWISE VFR CONDITIONS WILL PREVAIL.

&&

.MARINE... 25/900 AM

MODERATE TO HIGH CONFIDENCE IN THE MARINE FORECAST.  NORTHWESTERLY
WIND GUSTS TO 25 KNOTS WILL PERIODICALLY FLOW ACROSS THE WESTERN
PORTION OF THE SANTA BARBARA CHANNEL AND THE NEARSHORE WATERS
BETWEEN POINT PIEDRAS BLANCAS AND POINT SAL DURING THE NEXT COUPLE
OF DAYS.  OTHERWISE CONDITIONS ACROSS THE COASTAL WATERS WILL REMAIN
BELOW ADVISORY LEVELS THROUGH MIDDAY WEDNESDAY.  WINDS WILL
STRENGTHEN ON WEDNESDAY AND SMALL CRAFT ADVISORIES MAY BE NEEDED FOR
THE OUTER WATERS WEDNESDAY NIGHT AND THURSDAY.

A SOUTHERLY SWELL WITH A LONG PERIOD WILL BRING MODERATE SURF TO
SOUTH FACING BEACHES OF LOS ANGELES AND VENTURA COUNTIES THROUGH AT
LEAST THIS EVENING. IN ADDITION...THERE WILL BE A HIGH RISK OF RIP
DANGEROUS CURRENTS TODAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
BEACH HAZARDS STATEMENT (SEE LAXCFWLOX).
HIGH RIP CURRENT RISK (SEE LAXSRFLOX).

&&
$$

PUBLIC...GOMBERG/DB
AVIATION/MARINE...RORKE/HOXSIE
SYNOPSIS...SWEET

WWW.WEATHER.GOV/LOSANGELES



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