Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 020019
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATE
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
520 PM PDT FRI AUG 1 2014

...UPDATED AVIATION DISCUSSION...

.SYNOPSIS...

HIGH PRESSURE EAST OF THE REGION WILL KEEP TEMPERATURES ABOVE NORMAL
THROUGH THE WEEKEND.  MONSOONAL MOISTURE WILL BRING A SLIGHT CHANCE
OF THUNDERSTORMS TO THE MOUNTAINS AND DESERTS THROUGH SATURDAY AND
TO MOST OF L.A. COUNTY AND THE COASTAL WATERS SUNDAY.  NIGHT AND
MORNING LOW CLOUDS WILL AFFECT MUCH OF THE COAST THROUGH THE PERIOD.

&&

.SHORT TERM (TODAY-MON)...MARINE LYR CLOUDS FINALLY MANAGED TO FORM
A SOLID LAYER OVERNIGHT AND ARE CONTINUING TO LINGER NEAR MUCH OF
THE COAST NORTH OF MALIBU THROUGH THE AFTERNOON. HASN`T REALLY HAD
MUCH IMPACT ON TEMPS AS THEY ARE VERY SIMILAR TO YESTERDAY OR
PERHAPS JUST A DEGREE OR TWO COOLER. INTERIOR SLO IN THE EXCEPTION
AT 3-6 DEGREES WARMER THAN YESTERDAY. CONVECTION SO FAR LIMITED TO
SOME SMALL CU OVER THE LA/VENTURA MTNS. MAY END UP REMOVING THAT
SMALL AREA OF SLIGHT CHANCE POPS OVER THE ERN SAN GAB MTNS IF MORE
SIGNIFICANT DEVELOPMENT ISN`T SEEN IN THE NEXT HOUR OR SO.

NOT EXPECTING MUCH CHANGE IN THE PATTERN TOMORROW. SIMILAR SKY
CONDITIONS AND TEMPERATURES. PERHAPS A SLIGHTLY BETTER CHANCE OF
AFTERNOON MTN/AV THUNDERSTORMS NEAR THE LA/SBD COUNTY BORDER AS
MOISTURE INCREASES FROM THE SOUTHEAST.

LA COUNTY CONTINUES TO BE ON THE WESTERN EDGE OF THE MONSOON
BOUNDARY, WHICH CAN BE OBSERVED QUITE WELL ON THE WATER VAPOR
IMAGERY. A WEAK TROF PUSHING INTO NRN CALIFORNIA IS PUSHING DRIER
AIR TO THE SOUTHWEST. MEANWHILE, A SIGNIFICANT MONSOON PUSH IS
BEGINNING AND SPREADING MOISTURE UP INTO SE CALIFORNIA ASSOCIATED
WITH A LARGE CYCLONIC CIRCULATION OVER SRN BAJA. LA COUNTY IS
CURRENTLY SANDWICHED BETWEEN THESE TWO AIR MASSES, HOWEVER MODELS
INDICATE THAT THIS BOUNDARY WILL SHIFT SLIGHTLY NORTHWEST BY
SATURDAY AFTERNOON, AND ESPECIALLY BY SUNDAY MORNING AS THAT BAJA
CIRCULATION MOVES NORTH INTO CALIFORNIA. MODELS ARE KEEPING THE
CENTER OF THE CIRCULATION OVER THE ERN CA DESERTS, BUT THE AIR MASS
IS QUITE MOIST WITH PWATS WELL OVER 1.5" AND IT WON`T TAKE MUCH TO
SQUEEZE OUT SOME SPRINKLES OR LIGHT SHOWERS OVER LA COUNTY LATE SAT
INTO SUNDAY. A COUPLE OF POSSIBLE NEGATIVE FACTORS INCLUDE THE
LIKELIHOOD THAT MOST OF VENTURA AND LA COUNTIES WILL BE UNDER AN
ALMOST SOLID SHIELD OF MID/HIGH CLOUDS THAT WILL LIKELY INHIBIT
CONVECTION WITHOUT THE PRESENCE OF THE VORT MAX WHICH WILL BE TO OUR
EAST AT THAT TIME. ALSO, MODELS AREN`T VERY UNSTABLE DURING THAT
TIME, THE NAM ESPECIALLY IS VERY UNDERWHELMING AND VERY DRY BELOW
700 MB. THE STEERING FLOW WILL BE FROM THE NORTH AND NORTHEAST SO
ANYTHING THAT DEVELOPS OVER THE DESERTS AND MTNS WILL DRIFT OFF OVER
THE VALLEYS AND COAST. BUT GIVEN THE THICK HIGH LEVEL MOISTURE IN
PLACE AND FAIRLY DRY LOW LAYERS IT SEEMS MORE LIKELY THAT IF WE SEE
ANY PRECIP IN OUR AREA IT WOULD BE IN THE FORM OF SPRINKLES OR LIGHT
SHOWERS, AND MOSTLY JUST LA COUNTY.

TEMPS SUNDAY WILL BE TRICKY WITH THE CLOUD COVER, BUT IT`S LIKELY
MANY LA/VENTURA COUNTY AREAS WILL SEE A SIGNIFICANT DROP IN HIGHS
FROM SATURDAY. COOLING ALSO EXPECTED FOR NORTHERN AREAS AS WELL, BUT
THE REASONING FOR THIS IS AN INCREASED ONSHORE PUSH WITH THE
ADVANCING TROF IN NRN CALIFORNIA.

MOISTURE EXPECTED TO BE EXITING THE AREA LATE SUNDAY INTO MONDAY
WITH MUCH MORE SUNSHINE EXPECTED MONDAY AFTERNOON FOR SOUTHERN
AREAS. THIS ALONE SHOULD FORCE A BOUNCE BACK IN HIGH TEMPS FOR
MONDAY OF AT LEAST A FEW DEGREES, POSSIBLY AS MUCH AS 10 DEGREES FOR
INTERIOR AREAS.

.LONG TERM (TUE-FRI)...MODELS IN GOOD AGREEMENT SHOWING A TROF
LINGERING ALONG THE WEST COAST FOR MUCH OF THE WEEK. THIS SHOULD
KEEP DAYTIME HIGHS A FEW DEGREES COOLER THAN THEY HAVE BEEN THIS
WEEK, BUT GENERALLY PRETTY CLOSE TO NORMAL. LIKELY PLENTY OF
NIGHT/MORNING LOW CLOUDS FOR COASTAL AND LOWER VALLEY AREAS WITH
CLEARING TO NEAR THE COAST EACH AFTERNOON. ALMOST ZERO THUNDERSTORM
THREAT WITH THE TROF KEEPING THE MONSOON BOUNDARY WELL TO THE EAST.

&&

.AVIATION...02/0015Z...GENERALLY HI CONFIDENCE IN THE 00Z TAFS. LOW
CLOUDS WITH LIFR/IFR/MVFR CONDITIONS ARE LIKELY TO AFFECT THE
COASTAL AIRFIELDS AT TIMES THRU SAT MORNING...WITH LOW CLOUDS
LINGERING INTO SAT AFTERNOON FOR KOXR. OTHERWISE...VFR CONDITIONS
CAN BE EXPECTED FOR THE AIRFIELD THRU SAT. GUSTY SW WINDS AT KWJF
AND KPMD WILL DIMINISH THIS EVENING THEN INCREASE AGAIN BY LATE SAT
AFTERNOON. THERE IS ALSO A SLIGHT CHANCE OF THUNDERSTORMS IN THE
VICINITY OF KWJF AND KPMD SAT AFTERNOON.

KLAX...GENERALLY HI CONFIDENCE IN THE 00Z TAF. LOW CLOUDS AND
IFR/MVFR CONDITIONS WILL AFFECT THE AIRFIELD TONIGHT INTO SAT
MORNING...THEN AGAIN SAT EVENING. OTHERWISE...VFR CONDITIONS CAN BE
EXPECTED.

KBUR...GENERALLY HI CONFIDENCE IN THE 00Z TAF WITH VFR CONDITIONS
EXPECTED THRU SAT AFTERNOON...ALTHO THERE IS A 20 PERCENT CHANCE OF
IFR CIGS LATE TONIGHT AND EARLY SAT.

&&

.MARINE...01/100 PM PDT
HIGH CONFIDENCE IN NO SMALL CRAFT ADVISORY CONDITIONS THROUGH AT
LEAST THE WEEKEND...EXCEPT FOR LOCAL GUSTS TO 25 KT NEAR POINT
CONCEPTION TONIGHT. MODERATE CONFIDENCE IN SOME SOUTHEAST WINDS
SOUTH OF POINT MUGU INCLUDING THE SAN PEDRO CHANNEL EACH MORNING
THROUGH THE WEEKEND. A DISTURBANCE WILL ROTATE THROUGH THE WATERS
SOUTH OF POINT MUGU ON SUNDAY WHICH MAY RESULT IN THUNDERSTORM
DEVELOPMENT. CONFIDENCE IS LOW ON THAT HOWEVER...AS THE DISTURBANCE
AND INSTABILITY IS WEAK...AND MUCH WEAKER THAN WHAT OCCURRED LAST
WEEKEND.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE

&&

$$

PUBLIC...MW
AVIATION...SIRARD
MARINE...KITTELL
SYNOPSIS...JLD

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