000
FXUS66 KLOX 141150 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
450 AM PDT SUN SEP 14 2008

UPDATED AVIATION SECTION

.SHORT TERM...
MARINE LAYER NEAR 1400 FEET WITH A 3MB EAST PUSH AND A 2MB NORTH
PUSH...WHICH IS ABOUT A MB LESS THAN THIS TIME LAST NIGHT. EDDY DOES
NOT SEEM AS AGGRESSIVE AS LAST FEW NIGHTS WHICH WOULD EXPLAIN THE
SLOW VLY PENETRATION. BUT BY DAWN MOST VLY LOCATIONS WILL HAVE A LOW
CLOUD COVER. BURN OFF SHOULD BE FAIRLY COMPLETE TODAY BUT INVERSION
WILL BE STRENGTHENING DURING THE DAY WHICH WILL KEEP IT LINGERING AT
SOME BEACH LOCATIONS. A LITTLE BOUNDARY LAYER WARMING TODAY WILL
BRING A COUPLE DEGREES WARMING TO INLAND AREAS. THE MARINE LAYER
WILL KEEP TEMPS SIMILAR TO SATURDAYS VALUES.

AN ODD LITTLE PATTERN SETS UP MONDAY A LARGE UPPER LOW SETS UP JUST
OFF THE NORTHERN COAST OF CALIFORNIA BUT ITS LOWEST HGT IS ONLY
580DM WHICH IS QUITE WARM OFF OVER IN NV A STRONG UPPER HIGH SETS UP
WITH 591DM HGTS. THIS HIGH WILL BE THE MAIN WEATHER MAKER MONDAY
ALTHOUGH THE LOW LOOKS LIKE IT SHOULD BE. GRADIENTS TREND STRONGLY
OFFSHORE AND MAY EVEN GO OFFSHORE IN THE EARLY MORNING HOURS. BL
TEMPS SHOOT UP 10 DEGREES C. THE OFFSHORE TRENDS AND INCREASING HGTS
WILL LIMIT THE MARINE LAYER TO THE COASTS. AFTERNOON TEMPS WILL
SHOOT UP 10 MAYBE 15 DEGREES FROM TODAYS MAX TEMPS.

THINGS GET MORE INTERESTING TUESDAY AS UPPER LOW OPENS UP AND MOVES
NORTHEAST OVER NORTHERN CALIFORNIA. THERE IS A POSSIBILITY THAT THE
SOUTH FLOW ASSOC WITH THE LOW WILL ENTRAIN SOME MID AND UPPER LEVEL
MOISTURE AND CREATE PARTLY CLOUDY SKIES. THE 00Z MDLS BACKED OFF A
LITTLE ON THE MOISTURE SO THINGS MAY BE SUNNIER THAN CURRENTLY
FORECAST. THERE DOES NOT LOOK LIKE ENOUGH MOISTURE FOR ANY TSTM
DEVELOPMENT.

AS THE UPPER LOW MOVES OVER THE INCREASE IN CYCLONIC FLOW...LOWER
HGTS...AND ONSHORE TRENDS SHOULD INCREASE THE MARINE LAYER AND ALL
THE COASTS WILL BE COVERED WITH LOCAL VLY PENETRATION LIKELY. WITH
THE DEEPER MARINE LAYER THE COASTS AND VLYS WILL COOL NICELY WITH
LESSER AMOUNTS OF COOLING OVER THE MTNS AND DESERTS WITH THE LOWER
HGTS.

.LONG TERM...
EC AND GFS IN GOOD AGREEMENT THROUGH SATURDAY AND THEN DIVERGE. GFS
ENSEMBLES POINT TO A LOWER CONFIDENCE FORECAST STARTING FRIDAY BUT
MOST OF THE ENERGY IS WELL NORTH OF US AND NOT TOO SURE HOW MUCH THE
DEVIATIONS WILL AFFECT THE WEATHER DOWN HERE. IN SHORT THERE IS
LIKELY GOING TO BE TROFING THROUGH AT LEAST FRIDAY WITH A PM/AM
CLOUD PATTERN AND TEMPS A LITTLE COOLER THAN NORMAL. A SMALL RIDGE
WILL BUILD IN LATER FRIDAY AND SATURDAY PROBABLY TOO LATE TO AFFECT
THE MARINE LAYER OR COASTAL TEMPS SATURDAY MUCH BUT INLAND TEMPS MAY
RISE A FEW DEGREES SATURDAY.

&&

.AVIATION...14/1150Z.
MVFR CONDITIONS SHOULD PERSIST AT COASTAL TERMINALS SOUTH OF POINT
MUGU...WHILE IFR CONDITIONS WILL DEVELOP OVER THE NEXT 90 MINUTES OR
SO AT COASTAL TERMINALS NORTH OF POINT MUGU AND VALLEY TERMINALS.
KSBA HAS A 60 PERCENT CHANCE OF REMAINING VFR THROUGHOUT THE PERIOD.
CLEARING SHOULD BE SLIGHTLY QUICKER LATER THIS MORNING/AFTERNOON.
VALLEY TERMINALS SHOULD CLEAR AROUND 16Z...WHILE COASTAL TERMINALS
SHOULD CLEAR BETWEEN 16Z AND 18Z NORTH...TO 17Z TO 21Z SOUTH. AN
EARLY RETURN OF THE MARINE LAYER IS LIKELY TONIGHT FOR
KLAX...KLGB...KSMX...AND KSBP. OTHERWISE...KPMD AND KWJF WILL REMAIN
VFR THROUGHOUT THE PERIOD.

KLAX...MVFR CONDITIONS WILL PERSIST WITH CEILINGS LIFTING ABOVE 1000
FEET BETWEEN 14Z AND 15Z. LOW CONFIDENCE EXISTS IN THE TIMING OF
CLEARING...BUT CLEARING SHOULD BE SLIGHTLY EARLIER...BETWEEN 19Z AND
21Z. VFR CONDITIONS SHOULD DEVELOP AFTER 21Z AND PERSIST THROUGH AT
LEAST 01Z...OR AS LATE AS 04Z WHEN THE STRATUS LAYER HAS A 70
PERCENT CHANCE OF RETURNING.

KBUR...IFR CONDITIONS HAVE A 70 PERCENT CHANCE OF DEVELOPING THROUGH
15Z. IF IFR CONDITIONS DEVELOP...VFR CONDITIONS SHOULD REDEVELOP
BETWEEN 16Z AND 17Z THIS MORNING AND WILL PERSIST THROUGHOUT THE
REMAINDER OF THE PERIOD.

&&

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

&&

$$

PUBLIC...RORKE
AVIATION...HALL

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