FXUS66 KLOX 281813
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1115 AM PDT TUE APR 28 2009

UPDATED AVIATION DISCUSSION

.SHORT TERM...DEEP MARINE LAYER RUNNING ABOUT 4500 FEET DEEP THIS
MORNING. SKIES WERE MOSTLY CLOUDY ACROSS THE ENTIRE AREA...WITH THE
EXCEPTION OF THE ANTELOPE VALLEY AND THE HIGHER ELEVATIONS AND
INTERIOR SLOPES OF THE MTNS THIS MORNING. WILL KEEP LOCAL DRIZZLE IN
THE FCST FOR THIS MORNING FOR CSTL AND VLY AREAS S OF PT
CONCEPTION...WITH ANY DRIZZLE MOST LIKELY IN THE FOOTHILLS AND
VALLEYS OF L.A. COUNTY. DEGREE OF CLEARING WILL BE A TRICKY
FCST TODAY. WITH THE MARINE LAYER SO DEEP...THERE COULD BE A REVERSE
CLEARING PATTERN...WITH CLOUDS LINGERING IN THE FOOTHILLS AND
VALLEYS INTO THE AFTERNOON. ON THE OTHER HAND...THE MARINE INVERSION
MAY WEAKEN ENOUGH TO ALLOW THE STRATUS TO BREAK UP THIS MORNING.
THIS IS LOOKING LIKE THE BETTER BET...SO EXPECT GOOD CLEARING IN
MOST AREAS. THE EXCEPTION COULD BE FOOTHILL AND VALLEY SECTIONS OF
L.A. COUNTY WHERE SOME STRATOCU COULD KEEP PTLY CLOUDY SKIES THIS
AFTERNOON. STRONG ONSHORE GRADS WILL MAKE FOR GUSTY WINDS IN THE
ANTELOPE VALLEY THIS AFTERNOON...AND WIND ADVISORIES MAY BE NEEDED
THERE. IT WILL BE ANOTHER VERY COOL DAY ACRS THE FCST AREA FOR LATE
APRIL..WITH MAX TEMPS 6 TO 12 DEGREES BELOW NORMAL IN MOST AREAS.

WITH A VERY WEAK INVERSION AND INCREASING NLY GRADS...EXPECT LESS
IN THE WAY OF LOW CLOUDS/FOG TONIGHT/WED MORNING. THIS WILL BE
ESPECIALLY TUE ACROSS SLO AND SBA COUNTIES...ALTHOUGH THERE SHOULD
BE SOME REDUCTION IN CLOUD COVER IN CSTL AND VLY AREAS OF L.A./VTU
COUNTIES AS WELL. EXPECT SOME GUSTY NWLY WINDS THROUGH THE
INTERSTATE 5 CORRIDOR AND THROUGH AND BELOW PASSES AND CANYONS OF
THE SANTA YNEZ RANGE TONIGHT AND EARLY WED...POSSIBLY NEAR ADVISORY
LEVELS. EXPECT MOSTLY SUNNY SKIES IN ALL AREAS BY WED AFTERNOON.
WITH SOME INCREASE IN HEIGHT AND THICKNESSES...AND SOME WARMING
IN THE BOUNDARY LAYER...EXPECT AT LEAST A FEW DEGREES OF WARMING
IN MOST AREAS ON WED.

A BROAD FLAT RIDGE DEVELOPS OVER THE W CST WED NIGHT/THU. EXPECT
ANOTHER ROUND OF GUSTY NWLY WINDS THROUGH THE INTERSTATE 5 CORRIDOR
AND THROUGH AND BELOW PASSES AND CANYONS OF THE SANTA YNEZ RANGE WED
NIGHT. WRF INDICATES EVEN LESS IN THE WAY OF STRATUS
WED NIGHT/THU...CONFINED MAINLY TO CSTL SXNS OF L.A. AND VTU
COUNTIES. TEMPS WILL BE UP SEVERAL MORE DEGREES ON THU ACROSS THE
ENTIRE REGION...BACK TO NEAR NORMAL LEVELS.

.LONG TERM...THE FLAT RIDGE WILL SHIFT TO THE E OF THE AREA
THU NIGHT AND FRI AS AN UPPER TROUGH MOVES INTO THE ERN PACIFIC.
SOME MID AND HIGH CLDS SHOULD BEGIN TO STREAM INTO THE REGION AS THE
RIDGE AXIS SHIFTS EWD. AS FOR STRATUS...WOULD EXPECT SOMEWHAT
BETTER COVERAGE...ESPECIALLY ON THE CENTRAL COAST...ALTHOUGH IT
SHOULD BE NOTED THAT THE 06Z WRF HAS BACKED OFF WITH RESPECT TO
STRATUS COVERAGE THU NIGHT/FRI MORNING. TEMPS MAY DROP A COUPLE OF
DEGREES ACROSS THE AREA ON FRI. THE FORECAST BEYOND FRI IS STILL A
LOW CONFIDENCE ONE. MODELS HAVE BEGUN TO TREND CLOSER TO EACH
OTHER...SHOWING THE TROUGH MOVING INTO THE W CST FRI NIGHT AND
SAT...POSSIBLY WITH ENOUGH MOISTURE AND ENERGY TO BRING SOME LIGHT
RAIN TO THE REGION...MAINLY N OF PT CONCEPTION. SLIGHT CHANCE POPS
ARE IN THE FCST FOR THESE AREAS FRI NIGHT/SAT...AND POPS MAY
HAVE TO BE ADJUSTED UPWARD THERE...AND POSSIBLY EXPANDED SWD IF
MODELS CONT TO SHOW THIS PATTERN. TEMPS SHOULD BE DOWN SEVERAL
DEGREES IN MOST AREA. RISING HEIGHTS AND WEAK RIDGING SHOULD FORCE A
SECOND IMPULSE TO PUSH INTO THE W CST AT A FARTHER N LATITUDE SAT
NIGHT/SUN...WITH THE THREAT OF RAIN LIKELY REMAINING N OF THE FCST
AREA. OTHERWISE...EXPECT JUST NIGHT THRU MORNING LOW CLOUDS
SAT NIGHT/SUN...WITH NOT MUCH CHANCE IN MAX TEMPS ON SUNDAY.
SOME WARMING IS EXPECTED ON MONDAY AS RIDGING BEGINS TO BUILD INTO
THE AREA.

&&


.AVIATION...28/1815Z.

SKIES WILL CONTINUE TO CLEAR ACROSS THE CENTRAL COAST AND EXPECT VFR
CONDS THROUGH THIS AFTERNOON WITH ONLY PATCHY LOW CLOUDS EXPECTED
ACROSS PORTIONS OF THE CENTRAL COAST INCLUDING KSMX. LOW CONFIDENCE
FOR STRATUS AT KSBP. OTHERWISE...LINGERING MVFR SCT-BKN CIGS WILL
CONTINUE ACROSS LA/VTU COUNTIES THROUGH 21Z...THEN CLEARING EXPECTED
FOR A FEW HOURS THIS AFTERNOON. EXPECT ANOTHER RESURGE OF MVFR CIGS
ACROSS LA/VTU COUNTY COASTAL AND VALLEYS ONCE AGAIN TONIGHT.
HOWEVER...LOW CONFIDENCE WITH TIMING. BEST GUESS BETWEEN 06-09Z.
SOME UDDF AND LLWS POSSIBLE NEAR KSBA THIS AFTERNOON AND EVENING.
ALSO GUSTY NW WINDS ACROSS CENTRAL COAST AND GUSTY SW TO W WINDS
ACROSS THE ANTELOPE VALLEY. REPORTS OF MOUNTAIN WAVE NEAR MOJAVE
EARLIER TODAY.

KLAX...SKIES SHOULD REMAIN MOSTLY CLEAR WITH SOME SCT STRATOCU TO
THE EAST LINGERING THROUGH 22Z. GOOD CONFIDENCE FOR VFR CIGS THROUGH
04Z...THEN MVFR CIGS EXPECTED OVERNIGHT WITH BURNOFF EXPECTED
EARLIER. NO WIND ISSUES.

KBUR...EXPECT VFR STRATACU THROUGH MID AFTERNOON HOURS...WITH
MODERATE CONFIDENCE FOR CLEARING SKIES LATE AFTERNOON. MODERATE
CONFIDENCE FOR CLEAR SKIES THROUGH THE OVERNIGHT HOURS. LOW
CONFIDENCE FOR MVFR CIGS BETWEEN 09-14Z. NO WIND ISSUES.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
SMALL CRAFT ADVISORY (SEE LAXMWWLOX).

&&

$$

PUBLIC...BRUNO
AVIATION...KAPLAN

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