FXUS66 KLOX 251219
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
339 AM PST FRI DEC 25 2009

.SYNOPSIS... 
A WEAK UPPER LEVEL RIDGE WILL CONTINUE TO KEEP CONDITIONS DRY ACROSS 
THE AREA SATURDAY. A SERIES OF WEAK STORM SYSTEMS MOVING THROUGH THE 
EASTERN PACIFIC WILL BRING A CHANCE OF RAIN TO THE REGION SATURDAY 
NIGHT THROUGH MONDAY...THEN DRY AND SEASONABLY COOL WEATHER IS
EXPECTED TUESDAY THROUGH THURSDAY.

&&

.SHORT TERM (TODAY-SUN)...JUST SOME HIGH CLOUDS ACROSS THE REGION 
EARLY THIS MORNING. SOME LOW CLOUDS HAVE BEGUN TO FORM ACROSS THE 
CSTL WATERS...AND DEW POINTS HAVE COME UP QUITE A BIT ACROSS THE 
CSTL PLAIN...BUT SUSPECT SKIES WILL REMAIN MOSTLY CLEAR THIS 
MORNING. ACROSS THE VALLEYS OF VTU COUNTY AND THE SANTA MONICA 
MOUNTAINS...TEMPS WERE AGAIN ALREADY NEAR FREEZING...SO THE FROST 
ADVISORIES LOOK GOOD THERE. TEMPS SHOULD REBOUND QUICKLY TODAY...AND 
SHOULD BE VERY SIMILAR TO THOSE REACHED THU...GENERALLY RIGHT AROUND 
NORMAL IN MOST AREAS. 

THE RIDGE ALONG THE WEST COAST WILL BREAK DOWN AND SHIFT EWD TONIGHT 
AND SATURDAY AS AN UPPER LOW SWINGS THROUGH THE ERN PACIFIC. HAVE 
LEFT THE MOSTLY CLEAR FCST FOR TONIGHT FOR THE TIME BEING...BUT THE 
06Z WRF SUGGESTS THAT THERE MAY ACTUALLY BE SOME LOW CLOUDS ACROSS 
AT LEAST THE CSTL PLAIN. HIGH CLOUDS SHOULD INCREASE ACROSS THE 
REGION ON SATURDAY...WITH THICKER CLOUDINESS ASSOCIATED WITH A 
WEAKENING FRONTAL SYSTEM MOVING INTO THE CENTRAL COAST DURING THE 
DAY. AS THE UPPER LOW LIFTS NEWD TOWARD THE PAC NW LATE SAT AND SAT 
NIGHT...SUPPORT FOR THE FRONTAL SYSTEM MOVING TOWARD THE W CST WILL 
DECREASE AND THE FRONT WILL FALL APART RATHER QUICKLY. RAIN WITH THE 
FRONT COULD MAKE IT INTO SLO COUNTY SAT AFTERNOON AND POSSIBLY INTO 
SBA COUNTY SATURDAY EVENING. THERE WILL BE SEVERAL DEGREES OF 
COOLING ACROSS THE ENTIRE AREA SAT. 

THE WRF SHOWS PLENTY OF LOW LVL MOISTURE SAT NIGHT...ASSOCIATED WITH 
THE DYING FRONT AND ALSO SOME WARM ADVECTION AHEAD OF THE NEXT 
UPPER LOW DROPPING THROUGH THE PACIFIC...THIS ONE FARTHER S.  
WL LEAVE SLIGHT CHANCE POPS IN FOR SAT NIGHT AND EARLY SUNDAY ACROSS 
THE ENTIRE AREA...BUT ALL MODELS ARE NOW SHOWING MORE RIDGING
DEVELOPING ACROSS THE REGION AHEAD OF THE SYSTEM SUNDAY. SO...EVEN 
IF SOME LIGHT RAIN DOES FALL SAT NIGHT/EARLY SUNDAY...THE THREAT 
MAY DECREASE DURING THE DAY. STILL...THERE SHOULD BE A FAIR AMOUNT 
OF CLOUDINESS ACROSS THE REGION ON SUNDAY AS TEMPS SHOULD REMAIN 
BELOW NORMAL.

  
.LONG TERM (SUN NIGHT-THU)...ALL MODELS ARE CONVERGING ON THE 
SOLUTIONS OF TRACKING THE UPPER LOW TO THE S AND W OF THE FCST 
AREA...KEEPING MUCH IF NOT ALL OF ITS RAIN JUST OFF THE COAST. WITH 
THE TRACK SO CLOSE...BLV IT IS PRUDENT TO LEAVE THE CHANCE OF RAIN 
FOR SUN NIGHT AND MONDAY...ALTHOUGH THERE IS INCREASING CONFIDENCE 
THAT MONDAY AFTERNOON WILL BE DRY. THEN...A NWLY FLOW PATTERN ALOFT 
WILL SET UP OVER THE FCST AREA TUE THRU THU...WITH DRY WEATHER 
EXPECTED...AND TEMPS SLIGHTLY BELOW NORMAL. 

&&

.AVIATION...

25/1130Z

GOOD CONFIDENCE IN TAFS. KLGB-KSMO MAY SEE MVFR VIS IN HZ BOTH THIS 
MORNING AND AFTER MIDNIGHT TONIGHT.

KLAX...GOOD CONFIDENCE IN TAF. A 30 PERCENT CHANCE OF MVFR VIS 
13Z-16Z.

KBUR...VERY GOOD CONFIDENCE IN TAF.
 
&&

.LOX WATCHES/WARNINGS/ADVISORIES...
FROST ADVISORY (SEE LAXNPWLOX).

&&

$$

PUBLIC...BRUNO
AVIATION...RORKE
SYNOPSIS...DB

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