021 
fxus66 klox 042003 rra 
afdlox 


Southwest California area forecast discussion 
National Weather Service Los Angeles/Oxnard California 
110 PM PDT Friday Jul 4 2008 


Short term... 
small trough moving through north of the area at the moment. SW flow 
ahead of the trough has entrained some tropical moisture which has 
caused partly cloudy skies today. The partly to mostly cloudy skies 
and increased onshore flow has lowered temperatures about 5 degrees north 
of Point Conception while south offshore trends both north and south 
have increased temperatures by 3 to 5 degrees. 


Some increased middle level moisture is moving up through Imperial 
County and into San Diego County. Think this moisture will make it 
to the San Jacinto Mountains but not into our County Warning Area...at worst it will 
make it a little more cloudy but an insignificant chance of thunder. 


Marine layer has been blown out by the trough and middle level moisture. 
A little better eddy is forecast to develop tonight...but think that 
the marine clouds will have a tough time reforming and think that 
the only areas that will see significant low clouds will be western 
sba County and the la County coast. 


Sundowners will occur tonight but sba-smx grads are trending onshore 
and there is very little upper support. This will only allow for a 
15 to 25 miles per hour event with local gusts to 30 miles per hour. 


Saturday will very similar to today except that it will be sunnier. 
Heights and bl temperatures are about the same. Central coast pressure grads 
will be like today while south of Point Conception will see onshore 
trends both north and south. This should allow temperatures to remain the 
same north of Point Conception and cool a couple of degrees coasts 
and valleys south of Point Conception. 


Saturday and Sunday has the upper level flow flatten out and the 
ridge that will affect the weather all next week begins to peak in 
out over the east Pacific. But overall there is little change in heights or 
thickness or pressure grads and there will be little change between 
Sat and sun. 


Long term... 
hot is the word for the upcoming week. GFS and ec are in decent 
agreement through Wednesday and GFS ensemble runs stay coherent 
through Wednesday as well. After that many differences appear in 
placement of the ridge trough pattern to the north and the placement 
of the upper high over the western US. 


Monday through Wednesday the upper high moves over California and 
temperatures will rise each day. Onshore flow will be reduced and whats 
left of the marine layer will be crushed to under 700 feet. This 
will allow for all areas except the immediate coast to warm nicely. 
As the high is transitioning over the state the middle level flow 
pattern will not be conducive to monsoon transport to the l.A. 
Mountains and the mountains should stay clear. 


With the models not preforming well past Wednesday do not have a great 
deal of confidence in the Thursday Friday forecast. In general it 
looks like the upper high will move to The Four Corners area. Heights 
should remain well above normal and there will be an increased risk 
of monsoon events. Mentioned a few build ups Thursday Friday for the 
l.A./Vta mountains and deserts but need better model agreement to put in 
probability of precipitation. 


&& 


Aviation... 


04/1830z. 
All taf sites will be mostly clear this afternoon...except the 
central coast and ksba perhaps dealing with a little bit of haze and 
smoke due to nearby fires. By late this evening...a shallow marine 
layer will struggle into the coastal tafs on the central coast and 
Los Angeles County. Otherwise...skies will remain mostly clear 
across the district into Saturday. 


Klax...good confidence in mostly clear skies until late this evening 
when the marine clouds return with MVFR to local IFR conditions. 
There is a 30 percent chance of a ceiling free night. 


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


&& 


Lox watches/warnings/advisories... 
Gale Warning (see laxcwflox). 
Small Craft Advisory (see laxcwflox). 


&& 


$$ 


Public...rorke 
aviation...Sweet 


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