089 
fxus66 klox 052352 
afdlox 


Southwest California area forecast discussion 
National Weather Service Los Angeles/Oxnard California 
452 PM PDT Sat Jul 5 2008 


Short term (tonight-tuesday)...northwest low-level flow continues 
over the area this afternoon. A general onshore trend is occurring 
this afternoon...but temperatures are within a couple of degrees 
of yesterday. Northwest flow low-level flow should begin to weaken 
over the next several days as a ridge of high pressure builds over 
the area. The thermal trough will shift westward and disturb the 
wind pattern for next week. High pressure over the central Pacific 
will shift east through the weekend...and build and strengthen 
over California coast. A general warming trend could start as 
early as Sunday for areas north of Point Conception...and will 
spread southward for the start of the work week. 


The effects of warming will start to occur Monday when gradients 
start trending offshore...the flow aloft lightens...and 950 mb 
temperatures warm. Temperature will likely soar past 100 degrees 
starting Monday over the foothill...valley...and desert locations. 
NAM-WRF 950 mb temperatures warm to near 40 celsius over the 
desert...and near 35 degrees celsius over the western San Fernando 
Valley. Further warming will occur on Tuesday...with the desert 
location nearing 110 degrees...and temperatures in the hottest 
valley locations exceeding 105 to near 110 on Tuesday. In 
addition...some middle-level moisture could slip into the area as a 
weak wave moves west around the ridge circulation. 


Long term (wednesday-saturday)...the door for monsoonal moisture 
should open on Wednesday...and temperatures should level 
off...however...it appears to be continued hot and humid for 
midweek and late week. The moisture should kick off isolated 
thunderstorms over the mountains and desert for midweek and late 
week. It still early to tell how far the moisture will spread over 
the area. The GFS 700 mb mixing ratios and 600 mb relative 
humidities have been the most aggressive with the 
moisture...possibly drifting some storms into the valley and 
coastal locations. However...the latest 18z solution of the GFS 
indicates a more drier solution. 


&& 


Aviation...05/2352z. 
VFR conditions expected to persist at all inland terminals except 
for occasional MVFR visibilities due to smoke and haze. A thinning 
marine layer along the central coast could keep any IFR to MVFR 
conditions from making it to ksbp...but ksmx will likely experience 
LIFR to IFR conditions after 04z. South of Point Conception...VFR 
conditions will persist through at least 09z. After 09z...it is 
likely that IFR to MVFR conditions will develop from koxr south. 


Klax...VFR conditions are expected to persist through 09z. A 60 
percent chance of IFR to MVFR conditions exists for klax and 
vicinity. If IFR to MVFR conditions develop after 09z...VFR 
conditions should redevelop after 13z...but it could be as late as 
15z. 


Kbur...VFR conditions expected throughout the period. 


&& 


Lox watches/warnings/advisories... 
Gale Warning (see laxcwflox). 
Special Weather Statement (see laxspslox). 


&& 


$$ 


Hall 


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