024 
FXUS66 KLOX 020556
AFDLOX

SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
1045 PM PDT SUN AUG 1 2010

NEW AVIATION DISCUSSION

.SYNOPSIS...

HIGH PRESSURE WILL STRENGTHEN OVER THE AREA ON MONDAY WARMING THE
AIR MASS THROUGH MIDWEEK. A COOLING TREND SHOULD OCCUR FOR THE
LATTER HALF OF THIS WEEK AS SOUTHWEST FLOW ALOFT DEVELOPS. NIGHT
THROUGH MORNING LOW CLOUDS AND FOG WILL PERSIST ALONG THE COAST.

&&

.SHORT TERM (TONIGHT-WED)...THE MARINE LAYER WAS ONLY AROUND 800 FT 
DEEP AT LAX THIS EVENING. LOW CLOUDS ALONG THE CENTRAL COAST ARE 
EXPECTED TO EXPAND OVER THE AREA AND INLAND THRU THE NIGHT.
LOW CLOUDS HAVE ALSO LINGERED ALONG THE VTU COUNTY COAST AND WERE 
MOVING INTO THE L.A. COUNTY COAST FROM MALIBU TO REDONDO BEACH. 
THESE LOW CLOUDS SHOULD EXPAND FURTHER AND COVER MUCH OF THE COASTAL 
PLAIN OVERNIGHT...WITH LITTLE IF ANY PENETRATION INTO THE ADJACENT 
VALLEYS. PATCHY DENSE FOG WILL BE POSSIBLE ALONG THE L.A. COUNTY 
COAST THIS EVENING AS WELL. OTHERWISE MOSTLY CLEAR SKIES CAN BE 
EXPECTED OVER MUCH OF THE REGION THRU TONIGHT.

UPPER LEVEL RIDGING OVER MUCH OF SRN CA IS EXPECTED TO PERSIST FOR 
THE MOST PART MON THRU TUE THEN WEAKEN ON WED AS A BROAD UPPER LEVEL 
TROF APPROACHES THE REGION FROM THE E PAC. THE MARINE LAYER PATTERN 
WILL CONTINUE WITH VARYING AMOUNTS OF NIGHT AND MORNING LOW CLOUDS 
AND FOG FOR MAINLY FOR COASTAL AREAS AND SOME OF THE ADJACENT 
VALLEYS...OTHERWISE MOSTLY CLEAR SKIES SHOULD PREVAIL IN GENERAL 
THRU WED. TEMPS MON AND TUE ARE EXPECTED TO BE NEAR NORMAL TO 
SLIGHTLY ABOVE NORMAL OVER INLAND AREAS AREAS...THEN COOL SLIGHTLY 
TO NEAR NORMAL TO SLIGHTLY BELOW NORMAL FOR WED. WITH GOOD ONSHORE 
FLOW CONTINUING...GUSTY SOUTHWEST AFTERNOON AND EVENING WINDS CAN BE 
EXPECTED DURING THE PERIOD FOR THE SANTA CLARITA VALLEY... PORTIONS 
OF THE MTNS AND INTO THE ANTELOPE VALLEY.

***FROM PREVIOUS DISCUSSION***

.LONG TERM (THU-SUN)...GOOD AGREEMENT EXISTS FOR SOUTHWEST FLOW 
ALOFT TO REDEVELOP ON THURSDAY AS A WEAK TROUGH APPROACHES THE WEST 
COAST. THE RIDGE WILL BE PUSHED EASTWARD BY THE TROUGH THROUGH LATE 
WEEK AND INTO THE WEEKEND. AN INCREASING ONSHORE FLOW AND A 
DEEPENING MARINE LAYER SHOULD DEVELOP. TEMPERATURES OVER THE WEEKEND 
COULD BE MUCH COOLER THAN FORECAST...ESPECIALLY IF EDDY CIRCULATION 
DEVELOPS. THE LATEST GFS SOLUTIONS INDICATE A LOW-LEVEL NORTHWEST 
FLOW DEVELOPING...AND WIND SPEED AND DIRECTION AT 950 MB COULD PERMIT
AN EDDY CIRCULATION TO DEVELOP. THERE COULD ALSO BE A PERIOD WHERE 
SUNDOWNER WINDS COULD DEVELOP OVER THE WEEKEND AS GFS SOLUTIONS 
INDICATE A DECENT AMOUNT OF THERMAL PACKING DEVELOPING ALONG A WEAK 
BOUNDARY.

A PATTERN SHIFT COULD BE ON THE HORIZON FOR THE EARLY HALF OF
NEXT WEEK AS THE HIGH PRESSURE OVER THE CENTRAL PACIFIC
STRENGTHENS AND COULD NOSE INTO THE WEST COAST. THIS COULD
POTENTIALLY BRING MUCH WARMER TEMPERATURES TO THE REGION TO START
NEXT WEEK.

&&

.AVIATION...

02/0035Z

600 FOOT MARINE LAYER WILL BRING LIFR/IFR CIGS AND VIS TO THE 
COASTAL SITES OVERNIGHT. NOT GREAT CONFIDENCE IN BURN OFF TIMES 
MONDAY MORNING WITH HIGHLY VARIABLE BURN OFFS EXPECTED.

KLAX...GOOD CONFIDENCE IN OVERNIGHT FCST WITH LIFR CONDS EXPECT VIS 
TO VARY CONSIDERABLY FROM MINUTE TO MINUTE. LOW CONFIDENCE IN BURN 
OFF WITH ANY TIME FROM 16Z-20Z EQUALLY LIKELY.

KBUR...GOOD CONFIDENCE IN TAF WITH ONLY A 20 PERCENT CHANCE OF CIGS 
FROM 13Z-16Z.

&&

.LOX WATCHES/WARNINGS/ADVISORIES...
NONE. 

&&

$$

PUBLIC...SIRARD/HALL
AVIATION...ASR
SYNOPSIS...B/HALL

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