040 
fxus66 klox 210542 cca 
afdlox 


Southwest California area forecast discussion...corrected 
National Weather Service Los Angeles/Oxnard California 
942 PM PST Thursday Nov 20 2008 


Short term (tonight-sun)...gusty northwest to north winds have developed over 
portions of the sba S coast and mountains this evening. The 
strongest winds have been over the Montecito hills area where a peak 
gust to 48 miles per hour was observed at the Montecito RAWS station. A Wind 
Advisory is in effect for the sba S coast and mountains tonight through 
3 am Friday...with the gusty winds below and through the passes and 
canyons. Some gusty winds have also been noted along the I-5 
corridor in northwest l.A. County as well which should continue overnight. 
Otherwise just some hi clouds out ahead of a weak upper disturbance 
will be moving over the district tonight. Some low clouds were 
developing over the western portions of the southern San Joaquin 
Valley and spilling over into the slow interior valleys. Low clouds 
should affect a larger portion of the interior valleys overnight. 
Low clouds were also along the san County coast...but with a broad 
low level weak offshore flow indicated by the WRF over the inner 
waters tonight...it looks like the low clouds should stay away from 
the l.A. Coast...with again just hi clouds moving over the region 
tonight. 


A flat upper ridge should linger over the forecast area through 
Friday...with a weak upper trough well SW of the region. The weak upper 
trough is forecast to move toward the Southern California coast through Sat. A broad 
upper trough will develop well off the Southern California coast Sat night and 
sun...with a broad SW flow aloft expected to develop out ahead of 
the upper trough by sun over Southern California. Dry weather is expected to 
prevail over the forecast area through sun. There may be a few more hi 
clouds at times otherwise generally fair skies can be expected through 
the period...except perhaps some marine layer clouds may develop 
along the l.A. Coast Sat night into Sun morning. Temperatures over the 
region are expected to remain a few degrees above normal for most 
areas through Friday...then cool back to near or even slightly below 
normal by sun as an onshore southerly flow increases. 


..from previous discussion... 


Long term (mon-thu)...southerly flow at low levels continues into 
Monday with weak south winds moving north of pt Conception. Marine layer 
clouds also expected to move into the central coast by Monday morning. 
After Monday, all bets are off. The 12z GFS totally flip-flopped on 
next week, keeping the upper low way off the coast and actually 
building a weak ridge along the West Coast for the middle of the 
week. Meanwhile, the European model (ecmwf) continues to favor a wetter solution. 
Given the uncertainty this far out I opted to not make any changes 
beyond Monday. Thus, the forecast continues to indicate a fair amount 
of clouds and near to slightly below normal temperatures. As far as probability of precipitation 
go, I left in the 10-15 probability of precipitation we had going and will see how this 
situation evolves over the next few days. Given the pattern and the 
time of year, this could be a situation where strong uncertainty in 
the forecast lingers into next week. 


&& 


Aviation...21/0535z...moderate confidence low clouds will stay away 
from klax and klgb overnight with just MVFR visibilities due to fog and 
haze expected through about 20z. Moderate confidence in LIFR conditions 
developing at kprb after about 11z until 18z. Otherwise...VFR conditions 
will prevail at the airfields through Friday evening. With gusty canyon 
winds expected in the vicinity of ksba tonight...low level wind shear conditions at 
times are expected at the airfield through 11z. Elsewhere no wind 
issues are expected through Friday evening. 


For klax...moderate confidence low clouds will not affect the 
airfield with just MVFR visibilities expected through about 20z. Otherwise VFR 
conditions are expected through Friday evening...with MVFR visibilities again 
developing after about 08z Friday night. No wind issues are expected. 


For kbur...high confidence in VFR conditions through Friday evening. No 
wind issues are expected during the period. 


&& 


Lox watches/warnings/advisories... 
red flag warning (see laxrfwlox). 
Wind Advisory (see laxnpwlox). 
Small Craft Advisory (see laxmwwlox). 


&& 


$$ 


Public...sirard/Wofford 
aviation...sirard 


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