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000
FXUS66 KLOX 191610
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
910 AM PDT SUN MAY 19 2013

.SYNOPSIS...
GUSTY NORTH WINDS ARE POSSIBLE THROUGH MONDAY MORNING FOR THE
MOUNTAIN AREAS. WARMING IS EXPECTED THROUGH MONDAY AS A RIDGE OF
HIGH PRESSURE BUILDS AND WEAK OFFSHORE FLOW DEVELOPS. AN INCREASE IN
NIGHT THROUGH MORNING LOW CLOUDS AND FOG...ALONG WITH A COOLING
TREND...IS THEN EXPECTED TUESDAY AND BEYOND AS LOW PRESSURE TO THE
NORTH INCREASES ONSHORE FLOW. COOL WEATHER AND PARTLY TO MOSTLY
CLOUDY CONDITIONS WILL LIKELY CONTINUE INTO NEXT WEEKEND.

&&

.SHORT TERM (TODAY-TUE)...
GUSTY NORTH WINDS CONTINUE OVER THE INTERIOR MOUNTAINS OF LA AND
VENTURA COUNTIES...AND THE ANTELOPE VALLEY THIS MORNING. THE WINDS
ARE BECOMING MORE ISOLATED TO THE MORE FAVORED PEAKS AND ARE
EXPECTED TO SUBSIDE BELOW ADVISORY LEVEL BY LATE THIS MORNING. A
VERY SHALLOW MARINE LAYER NORTH OF POINT CONCEPTION PRODUCED PATCHY
LOW CEILINGS OVER THE NORTHERN SANTA BARBARA COUNTY...BUT THIS IS
DISSIPATING RAPIDLY AND MAINLY CLEAR SKIES WILL PREVAIL THROUGH THE
REMAINDER OF THE DAY. FURTHER SOUTH THE MARINE LAYER IS LIFTING AND
SCATTERED CLOUDS REMAIN OVER THE EASTERN LA BASIN AND SAN GABRIEL
VALLEY. BY EARLY THIS AFTERNOON EXPECT ALL AREAS TO BE SUNNY.

HEIGHTS ALOFT WILL RISE TODAY AS A RIDGE OVER THE EASTERN PACIFIC
SHIFTS TOWARD THE COAST. THIS IN COMBINATION WITH CONTINUED ONSHORE
FLOW WILL PRODUCE A FEW DEGREES OF WARMING TODAY COMPARED TO
YESTERDAY. COASTAL AREAS WILL BE IN THE LOWER TO MID 70S WITH INLAND
HIGHS IN THE MID TO UPPER 80S.

.FROM PREVIOUS DISCUSSION...
RESPECTABLE OFFSHORE FLOW DEVELOPS TONIGHT AND THE ONLY LOW CLOUDS
WILL BE NEAR LONG BEACH WHICH IS WELL SHELTERED FROM THE OFFSHORE
FLOW. OFFSHORE FLOW AND 584DM HGTS WILL COMBINE TO MAKE MONDAY THE
WARMEST DAY OF THE NEXT 7 WITH MAX TEMPS 4 TO 8 DEGREES ABOVE NORMAL.

THE FLOW SWITCHES TO ONSHORE MONDAY NIGHT AND AN EDDY SPINS UP WHICH
WILL CREATE A FAIRLY EXTENSIVE CLOUD DECK. HGTS ARE FAIRLY HIGH AND
THIS SHOULD KEEP THE LOW CLOUDS SMOOSHED OUT OF THE VLYS.

THE LOW CLOUDS WILL LAST UNTIL MID MORNING AND THEN SKIES WILL BE
SUNNY. MAX TEMPS WILL FALL TO NEAR NORMAL.

.LONG TERM (WED-SAT)...
NO CHANGE IN LONG TERM THINKING THROUGH THURSDAY AS A COLD UPPER LOW
SETS UP SHOP OVER OREGON AND SPINS. THE RESULTANT CYCLONIC
FLOW...LOWERING HGTS...AND ONSHORE FLOW WILL CREATE A DEEP VLY
PENETRATING MARINE CLOUD LAYER THAT WILL LIKELY STRUGGLE TO CLEAR
THE BEACHES. MAX TEMPS WILL BE BLO NORMAL.

MDLS DISAGREE ON WHAT WILL BECOME OF THE UPPER LOW FRIDAY AND SAT
BUT ALL AGREE THAT THERE WILL BE SOME SORT OF TROF OVER THE WEST
COAST. DO NOT THINK THERE WILL BE MUCH CHANGE TO THE FORECAST AND
THE NIGHT THROUGH MORNING LOW CLOUDS WILL CONTINUE AS WILL THE BELOW
NORMAL MAX TEMPS.

&&

.AVIATION...
19/1135Z.

EXPECT VFR CONDS THRU THE PERIOD EXCEPT FOR AREAS OF IFR CIGS
ACROSS SOUTHERN PORTIONS OF THE CENTRAL COAST...THE SANTA YNEZ
AND SAN GABRIEL VALLEYS THROUGH MID MORNING. THERE WILL BE MVFR
CIGS ACROSS MUCH OF THE L.A. COUNTY COASTAL PLAIN THROUGH MID OR
LATE MORNING.

GUSTY NW WINDS WILL AFFECT THE MOUNTAINS THIS MORNING. GUSTY NW
WINDS WILL LIKELY DEVELOP THRU AND BELOW PASSES AND CANYONS OF SRN
SBA COUNTY THIS EVENING AND CONTINUE THROUGH LATE TONIGHT...WITH
LLWS AND UDDF IN THE VCNTY OF KSBA.


KLAX...MODERATE CONFIDENCE IN 12Z TAF. THERE IS A 30 PERCENT CHANCE
THAT CONDS WILL REMAIN VFR THIS MORNING.

KBUR...HIGH CONFIDENCE IN 12Z TAF WITH VFR CONDITIONS EXPECTED
THROUGHOUT THE PERIOD.

&&

.FIRE WEATHER...

(FROM PREVIOUS DISCUSSION)

GUSTY NORTHWEST WINDS WITH WARMING TEMPERATURES AND LOWERING
HUMIDITIES WILL BRING ELEVATED FIRE DANGER THROUGH SUNDAY ACROSS
PORTIONS OF THE FORECAST AREA THIS WEEKEND. WINDIEST LOCATIONS ARE
EXPECTED TO BE THE MOUNTAINS (ESPECIALLY I-5 CORRIDOR AND SANTA YNEZ
RANGE)...SBA SOUTH COAST...AND ANTELOPE VALLEY. THE STRONGEST WINDS
ARE EXPECTED TO OCCUR TONIGHT...WHEN GUSTS WILL GENERALLY BE IN THE
35 TO 45 MPH RANGE ACROSS THESE AREAS...EXCEPT ISOLATED GUSTS OVER
50 MPH NEAR RIDGETOP LEVEL. THESE WIND PRONE AREAS WILL ALSO SEE
HUMIDITIES FALL INTO THE TEENS EACH DAY.

BY LATE SUNDAY NIGHT AND MONDAY...SURFACE HIGH PRESSURE BUILDS INTO
THE GREAT BASIN...SETTING THE STAGE FOR A BRIEF OFFSHORE WIND EVENT
FOR THE REGION. THE PROJECTED LAX-DAGGETT GRADIENT IS ONLY EXPECTED
TO BE AROUND -2 MB...BUT THERE IS SOME UPPER LEVEL WIND SUPPORT.
OFFSHORE WINDS ARE EXPECTED TO DEVELOP ACROSS THE MOUNTAINS LATE
SUNDAY NIGHT...THEN DESCEND INTO THE VALLEYS ON MONDAY MORNING. AT
THIS TIME...WIND GUSTS IN THE 35 TO 40 MPH RANGE CAN BE EXPECTED IN
THE MOUNTAINS ON MONDAY MORNING...WITH GUSTS IN THE 25 TO 35 MPH
RANGE ACROSS THE VALLEYS (MAINLY SANTA CLARITA AND EASTERN VENTURA
VALLEYS). THERE WILL LIKELY BE WIDESPREAD HUMIDITIES IN THE LOWER TO
MID TEENS ON MONDAY ACROSS THE MOUNTAINS AND VALLEYS OF LOS ANGELES
AND VENTURA COUNTIES. WHILE THIS OFFSHORE WIND EVENT DOES NOT APPEAR
TO BE STRONG ENOUGH OR HAVE SUFFICIENT DURATION TO WARRANT A RED FLAG
WARNING...THERE WILL BE ELEVATED FIRE DANGER ACROSS THE MOUNTAINS AND
VALLEYS ON MONDAY. THE OFFSHORE WINDS ARE EXPECTED TO DIMINISH FAIRLY
RAPIDLY ON MONDAY AFTERNOON...THEN SHIFT TO ONSHORE ON TUESDAY.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
WIND ADVISORY (SEE LAXNPWLOX).
GALE WARNING (SEE LAXMWWLOX).
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...RORKE/SMITH
AVIATION...DB
SYNOPSIS...SUKUP

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