FXUS66 KLOX 302336
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
340 PM PST MON NOV 30 2009

UPDATED AVIATION DISCUSSION

.SYNOPSIS...

TUESDAY IS EXPECTED TO BE WARM WITH WEAK OFFSHORE WINDS. ON  
WEDNESDAY SEASONAL TEMPERATURES WILL RETURN WITH FAIR WEATHER 
CONTINUING THROUGH SATURDAY. THERE IS A CHANCE OF RAIN EARLY NEXT 
WEEK.

&&

.SHORT TERM (TODAY-THU)...OFFSHORE FLOW WILL BE WEAKENING OVER THE 
NEXT 12 TO 24 HOURS. AT THE SAME TIME, HIGH PRESSURE ALOFT WILL BE 
WEAKENING AS A WEAK LOW PRESSURE AREA UNDERCUTS THE WEST COAST 
RIDGE. THIS WILL INITIATE A COOLING TREND ACROSS THE AREA TUESDAY, 
MAINLY FOR COAST AND VALLEY AREAS, THEN ALL AREAS WED AS THE MARINE 
LYR LIKELY RETURNS. MAY ALSO GET ENOUGH HIGH CLOUDS WITH THE UPPER 
LOW TO WARRANT A PARTLY CLOUDY FORECAST FOR WED BUT NO 
PRECIPITATION. 

THE UPPER LOW WILL SLIDE SOUTH OF THE AREA WED NT AND THU AS THE 
WEST COAST RIDGE REBUILDS FOR LATER IN THE WEEK. WEAK OFFSHORE FLOW 
WILL REDEVELOP THU BEHIND THE TROF PASSAGE, BUT THIS MAY NOT HAPPEN 
SOON ENOUGH TO SCOUR OUT THE LOW CLOUDS, ESPECIALLY ACROSS THE SRN 
PORTION OF OUR FORECAST AREA. AS A RESULT, ANY WARMING ON THU WILL 
BE MINIMAL, PROBABLY NO MORE THAN A FEW DEGREES AT BEST.

.LONG TERM (FRI-MON)...OFFSHORE FLOW WILL "PEAK" FRI, THOUGH WINDS 
SHOULD REMAIN BELOW ADVISORY LEVELS. HOWEVER, ANY MARINE LYR CLOUDS 
SHOULD BE GONE BY THEN SO HIGHS ON FRIDAY SHOULD JUMP UP 3-6 DEGREES 
MOST AREAS. 

BEYOND FRIDAY THE FORECAST GETS COMPLICATED. MODEL TO MODEL AND EVEN 
RUN TO RUN CONSISTENCY IS VERY LOW FOR THE WEEKEND INTO EARLY NEXT 
WEEK, BUT THERE DOES SEEM TO BE GENERAL CONSENSUS ON AN OMEGA 
BLOCKING PATTERN SETTING UP, WITH THE HIGH CENTERED WELL NORTH INTO 
THE GULF OF ALASKA. THE TRICKY PART IS WHAT WILL HAPPEN WITH THE 
UPPER LOW ON THE EAST SIDE OF THE OMEGA BLOCK. THE CANADIAN AND TO 
SOME DEGREE THE GFS SHOW THE UPPER LOW DROPPING SOUTH ALONG THE WEST 
COAST SIMILAR TO AN INSIDE SLIDER PATTERN WITH THE UPPER LOW 
CENTERED SOMEWHERE OVER CENTRAL OR SOUTHERN CALIFORNIA LATE SUN AND 
MONDAY. THE ECMWF ON THE OTHER HAND KEEPS THE UPPER LOW WELL TO OUR 
NORTH OFF THE COAST OF OREGON. MEANWHILE, THE SOUTHERN BRANCH OF THE 
JET STREAM WILL START TAPPING INTO SOME SUBTROPICAL MOISTURE 
STREAMING ACROSS THE PACFIC. THIS MOISTURE COULD PLAY A SIGNIFICANT 
ROLE IN OUR WEATHER EARLY NEXT WEEK, BUT THE POSITION OF THE 
PREVIOUSLY MENTIONED UPPER LOW WILL BE CRITICAL IN DETERMINING WHERE 
THAT MOISTURE GOES. A FARTHER SOUTH POSITION AS DEPICTED BY THE 
CANADIAN AND GFS WOULD LIKELY PUSH THAT MOISTURE TOO FAR SOUTH WITH 
JUST LIMITED IMPACT LOCALLY. HOWEVER, THE ECMWF SOLUTION IS MUCH 
MORE INTERESTING AND COULD REALLY PUT US IN A WET PATTERN WITH A 
LONGER DURATION OF SOUTHERLY FLOW ALOFT. THERE'S REALLY NO WAY TO 
TELL AT THIS POINT HOW THE PATTERN WILL EVOLVE, BUT THERE CERTAINLY 
IS THE POTENTIAL FOR SOME SIGNIFICANT RAIN LATE IN THE WEEKEND INTO 
EARLY NEXT WEEK. ON THE FLIP SIDE OF THAT THOUGH, A GFS/CANADIAN 
SOLUTION WOULD PROBABLY RESULT IN JUST A BRIEF SHOT OF PRECIPITATION 
AS THE LOW MOVES THROUGH THE AREA SUNDAY OR EARLY MONDAY, WITH DRIER 
NORTHERLY FLOW SETTING UP RAPIDLY BEHIND THE TROF. THERE IS CERTAIN 
TO BE SEVERAL VARIATIONS OF THESE SOLUTIONS OVER THE NEXT FEW DAYS, 
BUT FOR NOW A 20-30 PERCENT CHANCE OF RAIN SUN/MON SEEMS LIKE A GOOD 
STATISTICAL STARTING POINT.

&&

.AVIATION...30/2340Z.
HIGH CONFIDENCE IN VFR AT ALL SITES THROUGH TUESDAY. ONLY EXCEPTION 
BEING KSMX WHERE LOOSELY SCATTERED LIFR FOG BANK JUST OFF THE COAST 
TRIES TO PUSH IN. STRATUS OF THE IFR/LIFR VARIETY SHOULD QUICKLY 
ADVANCE IN BY TUESDAY EVENING OVER MOST COASTAL SITES...WITH A 30 
PERCENT CHANCE OF IT COMING IN DURING THE AFTERNOON.

KLAX...HIGH CONFIDENCE IN VFR THROUGH 18Z TUE. 30 PERCENT CHANCE OF 
CIGS BELOW 005 COMING IN AFTER 20Z TUE...WITH A HIGHER CHANCE OF IT 
COMING IN AFTER 04Z WED. 

KBUR...HIGH CONFIDENCE IN VFR THROUGH PERIOD. WEAK LLWS WILL 
CONTINUE TO BE A CONCERN THROUGH 04Z WITH THE NORTH WINDS.

&&

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

&&

$$

PUBLIC...WOFFORD
AVIATION...KITTELL
SYNOPSIS...STERN

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