000
FXUS66 KLOX 182059
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
200 PM PDT THU SEP 18 2008

.SHORT TERM (TODAY-SUN)...A FEW CLOUDS IN THE VTU/LA MTNS AND
ANTELOPE VALLEY TODAY BUT VERTICAL DEVELOPMENT HAS BEEN CAPPED AT A
PRETTY LOW LEVEL. WITH STILL SOME MORE AFTERNOON HEATING TODAY THESE
CLOUDS COULD STILL DEVELOP INTO SOME WEAK STORMS SO WILL LEAVE IN
THE SLIGHT CHANCE THROUGH THIS EVENING. AIRMASS MUCH DRIER FRI-SUN
SO NO CONVECTION EXPECTED BEYOND THIS EVENING.

MARINE LYR WILL BE TRICKY TONIGHT, AS USUAL. LOW CLOUDS ARE MOVING
RAPIDLY AWAY FROM THE COAST THIS AFTERNOON BUT MODELS SHOW AT LEAST
SOME CLOUDS RETURNING TONIGHT ALONG THE CENTRAL COAST AND COASTAL
VENTURA AND LA COUNTIES. NAM ALSO SHOWS PLENTY OF LOW LVL RH INTO
THE SOUTHERN SALINAS VALLEY LATER TONIGHT SO LOW CLOUDS HAVE BEEN
ADDED TO THAT ZONE. BUT OVERALL CONFIDENCE IS VERY LOW, ESPECIALLY
GIVEN THAT THE GRADIENT TRENDS ARE EITHER NEUTRAL OR SLIGHTLY
NEGATIVE.

PROBABLY LITTLE CHANGE IN TEMPS FRIDAY. HOWEVER, WITH THE TROF
MOVING ONSHORE OVER NRN CA FRIDAY NIGHT WE SHOULD SEE SOME COOLING
MOST AREAS SAT. NORTHERLY FLOW DEVELOPING BEHIND THE TROF FRIDAY
NIGHT SHOULD ALSO BRING SOME GUSTY SUNDOWNER WINDS TO THE SANTA
BARBARA AREA THROUGH SATURDAY MORNING, POSSIBLY APPROACHING ADVISORY
LEVELS.

TROF MOVES INLAND SATURDAY, HOWEVER WE DON`T SEE MUCH CHANGE IN THE
OVERAL TEMPERATURE OF THE AIRMASS AS HEIGHTS AND THICKNESSES AS WELL
AS 950 TEMPS REMAIN ABOUT THE SAME. THE ONLY EXCEPTION WILL BE THE
INTERIOR PORTION OF SLO COUNTY WHERE A FEW DEGREES OF WARMING IS
EXPECTED.

.LONG TERM (MON-THU)...A TROF MOVING THROUGH THE PAC NW WILL KEEP
DAYTIME TEMPS ABOUT THE SAME MONDAY. BOTH THE ECMWF AND GFS MOVE
THIS TROF RAPIDLY INLAND, BUT FOR SOME REASON THE GFS BUILDS A
STRONG SURFACE HIGH OVER NEVADA AND CREATES A PRETTY STRONG OFFSHORE
FLOW PATTER. GIVEN THE TRAJECTORY OF THE TROF THIS SEEMS WAY
OVERDONE AND I HAVE MORE FAITH IN THE ECMWF WHICH INDICATES
GRADIENTS NEAR NEUTRAL. BOTH MODELS DO SHOW HIGH PRESSURE BUILDING
OVER THE AREA TUE-THU AND CONFIDENCE IS HIGH THAT WE`LL SEE A
SIZABLE WARMING TREND DURING THIS PERIOD.

&&

.AVIATION...18/1830Z.
MOSTLY CLEAR SKIES WILL CONTINUE THROUGH THIS EVENING BEFORE LOW
CLOUDS AND FOG RETURN TO ALL THE COASTAL TAFS SOMETIME AROUND
MIDNIGHT...GIVE OR TAKE A COUPLE OF HOURS. MVFR TO IFR CONDITIONS
ARE THEN EXPECTED THROUGH MID MORNING ON FRIDAY. VALLEY TAFS WILL
LIKELY REMAIN CLEAR THROUGH FRIDAY.

KLAX...CLEAR SKIES THROUGH ABOUT MIDNIGHT...THEN A 70 PERCENT CHANCE
OF LOW CLOUDS AND FOG WITH MVFR TO IFR CONDITIONS FROM MIDNIGHT
THROUGH MID MORNING FRIDAY.

KBUR...A 70 PERCENT CHANCE OF CLEAR SKIES THROUGH FRIDAY.

&&

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

&&

$$

PUBLIC...WOFFORD
AVIATION...SWEET

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