Weather

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fxus66 klox 112032 
afdlox 


Southwest California area forecast discussion 
National Weather Service Los Angeles/Oxnard California 
130 PM PDT Sat Oct 11 2008 


Short term (today-tue)...upper low moving into Utah today but a 
good west to northwest flow aloft remains along with strong cold air 
advection. This will keep cool and breezy conditions in many areas 
through this evening, though winds should be below advisory levels. 
As the low continues to moves east tonight and surface high pressure 
builds into Nevada, gradients will trend strongly offshore and winds 
will shift to a more northeasterly direction. This will cause 
adiabatic warming in the Lee of the mountains but continued cold air 
advection will keep the mountains and deserts still well below 
normals. In fact, highs on Sunday and Monday will be warmest at the 
coast, with valley temperatures at or slightly lower and much cooler in the 
mountains and deserts. Overnight lows will be chilly in wind protected 
locations and a frost advisory is in effect for interior slow and sba 
counties as well as the Antelope Valley late tonight and early sun. 
Will likely need another one for Monday morning as well. Temperatures will 
also drop into the 30s along the central coast and in wind protected 
locations of la, Ventura, and southern sba counties. 


Offshore flow will turn into a full blown Santa Ana wind event 
Monday and Tuesday, and in fact models are now showing the best 
upper level support Tuesday rather than Monday. Either way it will be a 
windy and dry couple of days across most of Ventura and Los Angeles 
counties and wind advisories and red flag warnings will be in 
effect. Wind gusts may approach or briefly exceed High Wind Warning 
levels in the mountains but I think overall an advisory should cover 
it. Along the central coast winds will be lighter but locally gusty 
north to northeast winds are possible below passes and canyons there 
as well. 


We should see several degrees of warming inland Tuesday as the last 
of the cold air associated with this upper low finally exits the 
area. 


Long term (wed-sat)...offshore flow weakens Wednesday and Thu, which 
should bring a little cooling at the coast, however little change in 
temperatures is expected in the valleys, while mountains and deserts 
should continue to warm up. Models start to diverge later next week 
with the GFS a little more robust and faster with a trough moving into 
the West Coast. The European model (ecmwf) maintains a high pressure ridge aloft 
through Friday, though both models show the trough moving onshore by 
Saturday. Additionally, most of the ensemble members also show some 
sort of troffing developing along the coast late next week. So for 
now i've trended temperatures downward Friday and Sat, though not quite 
as much as the GFS would suggest. And for now have left skies clear, 
though a marine layer return is quite possible either Friday or Sat, 
especially if the GFS solution verifies. Clouds would also have to 
be increased along the central coast as the trough nears Sat and middle 
level moisture increases with the frontal boundary. 


&& 


Aviation...11/1750z... 
high confidence in VFR Cat everywhere through tonight. Only 
exception being small possibility of kwjf seeing reduced visible from 
bldu...but likelihood much less than yesterday. Gusty northwest winds again 
today...but weaker than yesterday. Low level wind shear may be a concern for kbur 
and kvny. Winds will weaken tonight in most places as things shift 
more northeast. 


Klax...high confidence in VFR through tonight. Moderate confidence 
in north winds shifting to west by 20z. Moderate confidence of gusts 
into the low 20 knots range from 20z to 02z. 


Kbur...high confidence in VFR through tonight. Low confidence of 
wind direction between 20z and 23z...but should be 10 knots or less. 


&& 


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


&& 


$$ 


Public...Wofford 
aviation...kittell 


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