Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 221113
AFDLOX

FXUS66 KLOX DDHHMM
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
337 AM PDT FRI MAY 22 2015

.SYNOPSIS...
AN UPPER LOW WILL BRING A CHANCE OF SHOWERS TO THE REGION TODAY.
WITH A THUNDERSTORM POSSIBLE IN SOME AREAS. THE WEATHER FOR THE
HOLIDAY WEEKEND WILL BE SLIGHTLY COOLER THAN NORMAL...BUT WILL MOST
LIKELY BE DRY. THERE WILL BE AREAS OF NIGHT THROUGH MORNING LOW
CLOUDS AND FOG WEST OF THE MOUNTAINS NEXT WEEK...BUT A SLOW WARMING
TREND IS EXPECTED...ESPECIALLY AWAY FROM THE COAST.

&&

.SHORT TERM (TODAY-SUN)...AN UPPER LOW WAS CENTER OVER VENTURA
COUNTY EARLY THIS MORNING. SCATTERED SHOWERS WERE AFFECTING THE
REGION. THE HEAVIEST SHOWER ACTIVITY WAS LOCATED ACROSS INTERIOR
SECTIONS OF SLO...NERN SBA COUNTY...AND WAS PUSHING INTO THE MTNS OF
VTU COUNTY. OTHER SHOWERS WERE DEVELOPING JUST TO THE SOUTH OF LOS
ANGELES COUNTY AS WELL. EXPECT A CHANCE OF SHOWERS IN ALL AREAS THIS
MORNING. A VORT LOBE MOVING ACROSS SOUTHERN SECTIONS OF THE FORECAST
AREA...WHERE THE COLDEST AIR ALOFT WILL BE...MAY BE SUFFICIENT
ENOUGH TO ALLOW FOR THE DEVELOPMENT OF A TSTM OR TWO ACROSS SOUTHERN
AND EASTERN LOS ANGELES COUNTY...ALTHOUGH THIS CHANCE IS QUITE LOW.
SHOWER ACTIVITY IS EXPECTED TO DECREASE THIS AFTERNOON...AND SKIES
MAY BECOME PARTLY CLOUDY...ESPECIALLY IN COASTAL SECTIONS FROM VTU
COUNTY NORTHWARD. IN THE MTNS OF L.A. AND VTU COUNTIES...THE WRF
SHOWS ENOUGH INSTABILITY TO KEEP A SLIGHT CHANCE OF TSTMS THROUGH
THE AFTERNOON. WHERE MEASURABLE RAIN OCCURS TODAY...TOTALS SHOULD
GENERALLY BE ONE TENTH OF AN INCH OR LESS...EXCEPT POSSIBLY ONE
QUARTER TO ONE HALF INCH IN ANY THUNDERSTORMS. SNOW LEVELS WILL BE
AROUND 6000 FEET...AND LOCAL SNOW ACCUMULATIONS OF AN INCH OR TWO
ARE POSSIBLE IN THE MTNS OF L.A. AND VTU COUNTIES. MAX TEMPS WILL BE
SEVERAL DEGREES BELOW NORMAL IN ALL AREAS TODAY. GUSTY SOUTHWEST TO
WEST WINDS MAY GET CLOSE TO ADVISORY LEVELS IN THE ANTELOPE VALLEY
THIS AFTERNOON.

AS THE UPPER LOW PULLS EAST OF THE REGION TONIGHT...THE SLIGHT
CHANCE OF SHOWERS IN THE L.A. AND VTU COUNTY MTNS WILL COME TO AN
END. N-S GRADIENTS WILL INCREASE A BIT...LIKELY PRODUCING SOME GUSTY
WINDS THROUGH AND BELOW PASSES AND CANYONS OF SRN SBA COUNTY...AND
THROUGH THE I-5 CORRIDOR. WINDS ARE EXPECTED TO REMAIN BELOW
ADVISORY LEVELS. THERE WILL BE PLENTY OF LOW LEVEL MOISTURE
LINGERING TONIGHT/SAT MORNING...SO EXPECT PLENTY OF CLOUDS...BUT
PROBABLY NOT A VERY ORGANIZES CLOUD DECK. STILL...EXPECT MOSTLY
CLOUDY SKIES...ESPECIALLY FROM THE COASTAL MTN SLOPES WWD...WITH
SKIES PROBABLY BECOMING PARTLY CLOUDY SAT AFTERNOON. MAX TEMPS MAY
BE UP A COUPLE OF DEGREES ON SAT...BUT TEMPS WILL LIKELY REMAIN
SEVERAL DEGREES BELOW NORMAL.

KIND OF A TRICKY FORECAST FOR SAT NIGHT/SUN. A RATHER STRONG VORT
LOBE IS FORECAST TO DROP SOUTH SOUTHWESTWARD FROM THE ROCKIES AND
EVOLVE INTO AN UPPER LOW AND IT MOVES SOUTH THROUGH CA SAT NIGHT AND
SUNDAY MORNING. THIS SYSTEM WILL HAVE VERY LITTLE MOISTURE TO WORK
WITH...BUT THE MODELS HAVE BEEN TRENDING STRONGER AND FARTHER WEST
WITH THE FEATURE. AT THIS TIME...WILL LEAVE POPS OUT OF THE
FORECAST...BUT SLIGHT CHANCE POPS MAY HAVE TO BE ADDED...AT LEAST
FOR THE MOUNTAINS. OTHERWISE...EXPECT PLENTY OF NIGHT THROUGH
MORNING LOW CLOUDS AND FOG WEST OF THE MTNS SAT NIGHT/SUN
MORNING...THEN PARTLY CLOUDY SKIES SUN AFTERNOON. MAX TEMPS WILL
REMAIN BELOW NORMAL...ALTHOUGH MAY BE UP A COUPLE OF DEGREES AS
HEIGHTS BEGIN TO RISE IN THE AFTERNOON OF THE BACK SIDE OF THE UPPER
LOW.


.LONG TERM (MON-THU)...A WEAK FLAT RIDGE WILL BUILD INTO THE REGION
FOR MEMORIAL DAY. AFTER A FAIR AMOUNT OF NIGHT THROUGH MORNING LOW
CLOUDS AND FOG IN COASTAL AND VALLEY AREAS...SKIES SHOULD BECOME
PARTLY CLOUDY MON AFTERNOON. MAX TEMPS MAY EDGE UP A BIT
MORE...ESPECIALLY IN THE MTNS AND DESERTS. AN UPPER LOW MOVING
THROUGH THE PAC NW AND A WEAK UPPER TROUGH APCHG THE REGION FROM THE
WEST WILL LIKELY KEEP COOL CONDITIONS TUE...WITH NIGHT THROUGH
MORNING LOW CLOUDS AND FOG IN COASTAL AND VALLEY AREAS. A BUILDING
RIDGE WILL LIKELY BRING A WARMING TREND TO THE REGION WED AND
THU...ESPECIALLY ACROSS THE INTERIOR VALLEYS...MTNS AND
DESERTS...AND NIGHT THROUGH MORNING STRATUS WILL PROBABLY BECOME
LESS WIDESPREAD.

&&

.AVIATION...19/1900Z...

AT 1748Z...A WEAK INVERSION WAS IN PLACE WITH THE MARINE LAYER DEPTH
OF 2500 FEET AND AN INVERSION TOP AT 4500 FEET WITH A TEMPERATURE OF
10 DEGREES CELSIUS.

LOW CONFIDENCE IN THE 18Z TAF FORECAST PACKAGE. WEAK WEATHER SYSTEMS
MOVING THROUGH THE REGION ARE CREATING HAVOC WITH THE MARINE
INVERSION AND MAKING IT DIFFICULT TO PIN DOWN THE EVOLUTION OF THE
CLOUD DECK AND LEADING TO FREQUENT CHANGES BETWEEN SCT AND BKN SKY
CONDITIONS. A BIG FORECAST QUESTION IS WHETHER MARINE CLOUDS WILL
RETURN TO AREAS SOUTH OF POINT CONCEPTION TONIGHT AND WEDNESDAY
MORNING WITH SUCH A WEAK INVERSION IN PLACE.

KLAX AND KBUR...LOW CONFIDENCE IN THE 18Z FORECAST. THERE IS A 50
PERCENT CHANCE OF CLEAR SKIES THROUGH THE NIGHT.

&&

.MARINE...22/300 AM.

OUTER WATERS...

SMALL CRAFT ADVISORIES HAVE BEEN ISSUED FOR ALL OUTER WATERS FOR
THIS AFTERNOON THROUGH SATURDAY NIGHT INTO SUNDAY MORNING. THERE
WILL BE A PERIOD OF WINDS DIMINISHING TO JUST BELOW SMALL CRAFT
ADVISORIES EARLY SATURDAY MORNING...BUT WILL INCREASE LATER IN THE
DAY.

INNER WATERS...

THERE WILL BE SMALL CRAFT ADVISORY WINDS FOR THE WESTERN PORTION OF
THE SANTA BARBARA COUNTY LATE THIS AFTERNOON AND OVERNIGHT.

SMALL CRAFT ADVISORY HAS BEEN ISSUED FOR THE OUTER WATERS SOUTH OF
POINT SAL AND THE WESTERN PORTION OF THE SANTA BARBARA. THERE IS A
80 PERCENT CHANCE THAT WINDS WILL INCREASE TO SMALL CRAFT LEVELS ON
FRIDAY AFTERNOON AND CONTINUE INTO FRIDAY NIGHT.

THE STRONGEST WINDS IN THE SANTA BARBARA CHANNEL WILL BE ACROSS THE
WESTERN PORTION AND MAY IMPACT THE REFUGIO OIL SPILL INCIDENT WITH
WIND WAVES UP TO 4 FEET. WIND GUSTS COULD APPROACH 25 KNOTS.

$$

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).
MARINE WEATHER STATEMENT (SEE LAXMWSLOX).

&&

$$

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

WWW.WEATHER.GOV/LOSANGELES


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