530 
fxus66 klox 072100 
afdlox 


Southwest California area forecast discussion 
National Weather Service Los Angeles/Oxnard California 
200 PM PDT Thursday Aug 7 2008 


Short term (today-sunday)... 
the upper level high to the east continues to interact with a broad 
trough trapped just off the California coast. This pattern allowed the high 
to slip a bit further to the north than yesterday...resulting in 
moist south to southeast flow over southeast California. With the moisture tap a 
smidge of cooling aloft...thunderstorms fired up overnight near the 
Mexican border...and have moved up to western San Bernardino County 
this afternoon. With the trough to our west...the moist southerly 
flow shifts southwesterly over la Colorado in a rather short distance. 
This southwest flow should keep thunderstorms and flooding concerns 
to the east of our area...but with some buildups over the 
mountains...left the slight chance riding in the la/vtu mountains and deserts 
through this evening. The chances drops off quite quickly west of 
the san Gabriels. The flow looks to shift further westerly overnight 
into Friday as the trough pushes eastward...and convective activity 
should shift further to the east. Therefore...not much is expected 
in and near our area Sat. 


The shallow marine layer near 800 feet deep has kept stratus formation 
to the central coast...with none to speak of south of pt Conception. 
With the warm sea surface temperatures and nearby convection...the stratus 
will continue to be difficult to forecast. The stratus should 
reappear over la/vtu counties sometime over the next few days...but 
cannot hang my hat on which day. Forecast reflects a conservative 
approach...with stratus along the coastal sections each day. 


As the previously mentioned upper level trough moves onshore north 
of the area Friday night...surface high pressure off the coast will 
build. West to northwest flow should increase over the area as a 
result Friday through sun. This should do a couple of things beyond 
some locally breezy conditions. The extra drying will further squash 
any convective threats and cool the fairly mild low temperatures we have 
experience lately. This will also bring a little daytime cooling to 
the immediate coasts...and should help push stratus a bit further 
into the la and Salinas valleys Friday night. The lowered thicks should 
also help areas north of Point Conception cool a bit as well. Other 
than that...with grads...thicks...and 950mb temperatures staying steady... 
difficult to justify much variation through the weekend. 


Long term (monday-thursday)... 
once the trough passes well to the east by sun...the upper level 
ridge will build to the west and settle over western Arizona by Monday. The GFS 
and European model (ecmwf) show modest heights and temperatures should stay fairly steady 
from the weekend through Tuesday...at just above normal for much of the 
area. Although timing is still off about 12 hours...the European model (ecmwf) and GFS 
are showing a bit more agreement with a trough sagging down into far 
northern California Wednesday and Thursday. Although at this point it does not look to have 
much affect on our boringly steady temperatures...it will push the high 
further to the east and allow it to build in strength. Although it 
is still far out in time...with the location of the high and the 
trough...there the solutions so a window of opportunity for some 
moist southerly flow over Southern California. Did not alter much in the forecast 
at this point. If this solution stays steady over the next few 
days...later shifts will have to address the addition of clouds and 
chances of thunderstorms. This pattern looks to also weaken onshore 
grads...and disrupt the marine layer. 


&& 


Aviation...07/1815z. 
Warm sea surface temperatures seem to be disrupting marine layer 
formation across the coast south of Point Conception. Kept taf sites 
free of low clouds and fog tonight...however a patch of low clouds 
and fog could still form...so only fair confidence in the tafs south 
of Point Conception. North of Point Conception...good confidence in 
a fairly typical night and morning low clouds and fog regime. 


Klax...only fair confidence in clear skies through Friday. If low 
clouds and fog do interfere with the airfield...such interference 
would not likely occur until after midnight with either MVFR or IFR 
conditions. 


Kbur...high confidence in clear skies through Friday. 


&& 


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


&& 


$$ 


Public...kittell 
aviation...Sweet 


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