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fxus66 klox 201139 aaa 
afdlox 


Southwest California area forecast discussion...updated 
National Weather Service Los Angeles/Oxnard California 
435 am PDT Sat Mar 20 2010 


Updated aviation section 


Synopsis... 
dry weather will continue through next week with warmer than normal 
temperatures expected over the weekend...then gradual cooling 
through early next week. 


&& 


Short term (today-mon)...an upper level ridge and weak offshore 
flow will bring a similar day to yesterday in regards to temperatures 
across much of the area. Offshore flow across the interior areas 
will not be quite as strong as yesterday. However...surface grads will 
remain near neutral. This should help the la/vtu County mountains and 
Antelope Valley warm a couple degrees today...while most other areas 
see little change. Although expecting mostly sunny skies today...a 
few high clouds will move through the ridge...especially in the northern 
zones giving partly cloudy skies at times. With the neutral lax-dag 
surface grads...some patchy low clouds and fog will form across the 
coastal areas of la County this morning....but should short lived. 
Sunday...the ridge will break down a bit...and onshore flow will be 
a tad stronger bringing a few degrees of cooling...especially across 
the coastal areas. Although 975 mb relative humidity looks rather dry...a few 
random patchy low clouds could develop once again tomorrow 
morning...especially across la coastal areas and possibly near Santa 
Maria. Expect hi temperatures in the upper 70s to around 80 in the warmest 
la/vtu County valleys. 


Temperatures should lower a few degrees on Monday as 500 mb and thickness levels 
lower a bit as an upper low approaches northern Baja California. Only lowered temperatures 
a degree or two as onshore flow remains quite weak. 975 mb continues 
to show drier conds as this low moves to the south of the 
regions...therefore expecting clear skies to a few patchy low clouds 
near the coast once again. Overall not much change expected in the 
short term forecast. 


Long term (tue-fri)... 
both GFS and European model (ecmwf) are in pretty good agreement through Tuesday as the 
approaching upper level low swings southward into Baja California and fills in. 
Meanwhile...another disturbance located over northern Utah retrogrades 
slightly to the southwest into southern Nevada. At this time...some early 
morning low clouds could affect the coastal areas...and temperatures will 
likely lower a few more degrees into the middle 70s in the warmest 
valleys and cooler along the coast. If the other area of low 
pressure over Utah does move closer Tuesday/Tuesday night as the European 
model shows...then breezy and cooler conds could be possible across 
interior portions of so cal. By Wednesday...weak area of high pressure 
builds back in over the region...which should warm temperatures a few 
degrees through Thursday. GFS advertises another quick moving trough into 
cal by Friday bringing additional cooling with a chance of low clouds 
across the coastal regions. Last two runs of the GFS indicated a 
chance of showers across the central coast late next weekend...and 
possibly so cal on sun. 


&& 


Aviation...20/1135z 


Neutral to weak offshore grads this morning. Some low clouds and fog 
will affect coastal sections of l.A. County through middle 
morning...then clouds should dissipate. 


Klax...MDT confidence in taf. LIFR ceilings and MVFR visibilities should burn 
off by 16z. There is a 20 percent chance that visibilities could drop into 
the LIFR category as well. 


Kbur...high confidence in ceiling and visibility unlimited taf next 24 hours. 




***Note*** 
the ASOS equipment at kbur...kvny...khhr...kcma...and koxr has a 
software error that may lead to incorrect cloud heights when there 
are two or more cloud layers present. Observations at kbur will be 
quality controlled 24 hours a day...observations at kvny will be 
quality controlled from 13z-07z...observations at koxr will be 
quality controlled from 15z-05z. Tafs for kvny and koxr will not be 
amended for ceilings during the time the observations are not monitored 
and there are two or more cloud layers present. 


&& 


Lox watches/warnings/advisories... 
none 


&& 


$$ 


Public...Kaplan 
aviation...Bruno 


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