000 
FXUS66 KLOX 082358 AAA
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
458 PM PDT SUN MAR 8 2009

...UPDATED AVIATION SECTION...

.SHORT TERM...
SKIES MOSTLY CLEAR TODAY WITH CONTINUED COOL CONDITIONS. UPPER TROUGH
WILL DIG INTO THE GREAT BASIN LATER TONIGHT AND MONDAY...WHICH
WILL HELP TO INCREASE THE ONSHORE FLOW. MODEL CROSS SECTIONS SHOWING
CONSIDERABLE DEEPENING OF MARINE LAYER...POSSIBLY UP TO 5000 FEET
BY MONDAY MORNING. DUE TO RAPID DEEPENING OF MARINE LAYER...LOOK FOR 
AREAS OF DRIZZLE TO DEVELOP. HAVE ALSO INTRODUCED 20 PERCENT POPS 
ACROSS LA COUNTY..AS 18Z WRF CONTINUES TO ADVERTISE SOME 
ACCUMULATING LIGHT RAINFALL. BEST THREAT OF MEASURABLE RAIN WILL BE 
FOOTHILL AND LOWER COASTAL SLOPES OF THE SAN GABRIELS.
OTHER AREA OF CONCERN WILL BE INCREASING WINDS ACROSS THE MOUNTAINS 
AND ANTELOPE VALLEY....WHERE GUSTS TO 40 MPH WILL BE POSSIBLE MONDAY
AFTERNOON INTO MONDAY NIGHT. THE INCREASE IN MARINE LAYER DEPTH AND 
ONSHORE FLOW WILL ALSO CREATE ADDITIONAL COOLING FOR MOST AREAS ON 
MONDAY. 

HIGH PRESSURE QUICKLY BUILDS IN BEHIND THE TROF MONDAY NIGHT AND
THE ONSHORE FLOW QUICKLY REVERSES OVERNIGHT. LOW HEIGHTS AND
FAIRLY DRY AIR WILL ALLOW FOR A COOL MONDAY NIGHT...WITH MOST AREAS
DOWN 5 TO 7 DEGREES BELOW NORMAL. WHILE THE OFFSHORE WINDS WILL
BE FAIRLY WEAK...IT DOES APPEAR THAT THE MARINE CLOUDS WILL
RETREAT. 

 .LONG TERM...
EC AND GFS IN GOOD AGREEMENT THROUGH FRIDAY AND THEN BEGIN TO 
DIVERGE SATURDAY BEFORE SPLITTING FOR GOOD SUNDAY AND BEYOND.
EARLIER 00Z EC RUN HAD A COLD FRONT BRINGING WIDESPREAD RAIN
TO THE REGION ON SUNDAY...BUT HAS BACKED OFF ON TIMING OF THIS
SYSTEM WITH 12Z RUN. 12Z GFS MEANWHILE HAS KEPT THIS SYSTEM
WELL TO OUR NORTH. FOR NOW...HAVE INTRODUCED SLIGHT CHANCE POPS
FOR SUNDAY...OTHERWISE DRY CONDITIONS WILL PREVAIL. 
 
&&

.AVIATION...08/2358Z.
NORTH OF POINT CONCEPTION...VFR CONDITIONS SHOULD PERSIST THROUGH AT 
LEAST 03Z...OR 08Z AT THE LATEST. IFR CONDITIONS WILL PUSH INTO THE 
TERMINALS NORTH OF POINT CONCEPTION...THEN GRADUALLY LIFT INTO THE 
MVFR CATEGORY BETWEEN 10Z AND 13Z MONDAY. VFR CONDITIONS SHOULD 
REDEVELOP AROUND 17Z. 

SOUTH OF POINT CONCEPTION...VFR CONDITIONS WILL PERSIST THROUGH 
05Z...THEN IFR CONDITIONS COULD SPREAD INTO THE COASTAL 
TERMINALS...AND LIFT TO THE MVFR CATEGORY AND SPREAD INTO THE VALLEY 
TERMINALS AFTER 10Z. LOW CONFIDENCE EXISTS IN CEILINGS AFTER 15Z.

KLAX...VFR CONDITIONS WILL PERSIST THROUGH AT LEAST 06Z...OR 11Z AT 
THE LATEST...WITH IFR TO MVFR CONDITIONS SPREADING INTO KLAX AND 
VICINITY. CEILINGS WILL LIFT INTO THE MVFR CATEGORY BETWEEN 10Z AND 
13Z. DRIZZLE...OR POSSIBLY LIGHT RAIN COULD DEVELOP BETWEEN 12Z AND 
16Z. LOW CONFIDENCE EXISTS IN THE CURRENT FORECAST AFTER 16Z.

KBUR...VFR CONDITIONS WILL PERSIST THROUGH AT LEAST 10Z...OR 12Z AT 
THE LATEST...WITH IFR TO MVFR CONDITIONS SPREADING INTO THE AREA. 
THERE IS A 30 PERCENT CHANCE THAT CEILINGS COULD ARRIVE IN THE IFR 
CATEGORY. DRIZZLE...OR POSSIBLY LIGHT RAIN COULD DEVELOP BETWEEN 14Z 
AND 17Z. LOW CONFIDENCE EXISTS IN THE CURRENT FORECAST AFTER 17Z.

&&

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

&&

$$

PUBLIC...GOMBERG
AVIATION...HALL

WWW.WEATHER.GOV/LOSANGELES