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fxus66 klox 211749 
afdlox 


Southwest California area forecast discussion 
National Weather Service Los Angeles/Oxnard California 
1050 am PDT Thursday Aug 21 2008 


Updated aviation discussion 


Short term....the forecast package was last updated around 6 am 
this morning...and looks consistent with current conditions...so do 
not see any need for an update at this time. 


Low clouds and fog were in the process of clearing nicely this 
morning and do not expect any changes to the maximum temperatures 
for today as compared to yesterday. 


For tonight and Friday...the nam12 does show some minor differences 
in the surface pressure pattern for this evening as opposed to 
previous runs with a stronger northwest pressure gradient. 
Therefore...may need to include some locally gusty winds across 
Santa Barbara County this evening...still well below advisory 
levels. Low clouds and fog did make it into the South Coast of Santa 
Barbara County this morning...despite the weak northwest 
gradient...and expect a similar scenario for Friday morning with an 
eddy circulation in the coastal waters bringing low clouds and fog 
to coastal sections and patchy marine clouds to the coastal valleys. 
Temperatures should demonstrate little in the way of change...aside 
from changes wrought by variations in marine cloud coverage. 


For Friday night and Saturday...the weather pattern begins a 
transition toward warmer weather on Saturday...with some modest 
temperature increases expected from the valleys to the inland 
sections. The marine layer will start to shrink a bit in depth and 
the coverage will be reduced somewhat. 


For Saturday night and Sunday...an upper level ridge centered in New 
Mexico will push in from the east and combined with weaker onshore 
flow...high temperatures on Sunday will spike upward considerably 
with warmest locations reaching the century mark. The marine layer 
will probably get suppressed to about 1000 feet or less during this 
period with minimal marine cloud areal coverage...confined to mainly 
the immediate coast. 


Long term...from previous discussion...the upper high will shift 
and expand westward Sunday...allowing for additional warming across much 
of the area...with temperatures possibly above normal in many locations. 
Middle and upper flow looks to be favorable to transport some monsoonal 
moisture into the area Sat night through Sun night...but models do not 
show very much moisture. The upper high will remain fairly strong 
Monday...so maximum temperatures will change little...then it will gradually 
weaken Tuesday and especially on Wednesday...so some cooling will begin. The 
marine layer should remain rather shallow through the period...keeping 
clouds confined to the coastal plain. 


&& 


Aviation 21/1750z... 
marine layer near 015 this morning...with stratus hugging the coast 
lines...but rather thin in depth. Moderate confidence in VFR cats 
prevailing everywhere through 00z...except for lingering MVFR ceilings 
at koxr through 20z or 21z. Some stratus may sneak back into klax or 
ksba as well...but likelihood is slim. Marine layer should not 
change over night...but low confidence once again in onset times. 
Biggest wildcard is just how much clearing occurs over the water 
this afternoon. Flight cats will be similar as last night...with 
LIFR at ksbp and ksmx...and low MVFR everywhere else. 


Klax...moderate confidence in VFR through this evening. Stratus near 
010 will linger along the coast...and cannot rule out an ob or two 
of a ceiling near 010 once the seabreeze kicks in...though chances are 
small. Stratus should return for good around 09z...but confidence in 
exact timing is still low with an onset window between 03z and 12z. 


Kbur...VFR will continue through tonight. Another 50/50 chance of 
ceilings near 008 with haze after 12z. 


&& 


Lox watches/warnings/advisories... 
Small Craft Advisory (see laxmwwlox). 


&& 


$$ 


Public...Sweet/Bruno 
aviation...kittell 


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