Area Forecast Discussion
Issued by NWS Los Angeles, CA

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FXUS66 KLOX 221308
AFDLOX

FXUS66 KLOX DDHHMM
AFDLOX

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

...UPDATED AVIATION DISCUSSION...

.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 CENTERED OVER VENTURA
COUNTY EARLY THIS MORNING. SCATTERED SHOWERS WERE AFFECTING THE
REGION. THE HEAVIEST SHOWER ACTIVITY WAS LOCATED ACROSS INTERIOR
SECTIONS OF SLO AND 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 ORGANIZED 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 ON 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...22/1210Z...

AT 1210Z...THERE WAS NO INVERSION NEAR LAX.

LOW CONFIDENCE IN THE 12Z TAF FORECAST PACKAGE. UPPER LOW WILL BRING
SOME PERIODIC SHOWERS ACROSS THE REGION THIS MORNING...THEN TAPER
OFF LATER THIS EVENING.  CIGS SHOULD BE MOSTLY MVFR/VFR. VISBYS
COULD LOWER TO IFR BRIEFLY WHERE SHOWERS ARE RELATIVELY STRONG. LOW
CONFIDENCE WITH STRATUS REDEVELOPMENT LATER TONIGHT. LIKELY MVFR
ONCE AGAIN IF AND WHERE STRATUS DEVELOPS. INVERSION WILL REMAIN WEAK
WHICH WILL CAUSE RANDOM LOW CLOUDS TO DEVELOP...BUT HIGHER THAN IFR.
30 PERCENT CHANCE FOR IFR CIGS FOR CENTRAL COAST EARLY SATURDAY
MORNING.

LAX...LOW CONFIDENCE WITH 12Z TAF IN RESPECT TO SHOWER CHANCES
TODAY. HIGHER CONFIDENCE THAT MVFR/VFR CIGS WILL STICK AROUND
THROUGH TONIGHT.

KBUR...LOW CONFIDENCE WITH 12Z TAF IN RESPECT TO SHOWER CHANCES
TODAY. EXPECTING MVFR/VFR CIGS WILL PREVAIL MOST OF THE DAY.

&&

.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.

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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