090 
fxus66 ksgx 172009 
afdsgx 


Area forecast discussion 
National Weather Service San Diego California 
200 PM PDT Wednesday Mar 17 2010 


Synopsis... 
weakening high pressure aloft and weakening offshore flow will 
bring... cooling...and patchy low clouds and fog to coastal areas 
beginning as early as Thursday morning. Temperatures could be lower 
along the coast this afternoon...then lower inland Thursday and 
Friday. High pressure will rebuild for the weekend bringing sunny 
and warm days. Cooler early next week as a stronger low pressure 
trough moves across the state. 


&& 


Discussion...for extreme southwestern California including Orange... 
San Diego...western Riverside and southwestern San Bernardino 
counties... 


This afternoon through Friday...offshore winds are weaker than 
yesterday...but maximum temperatures for inland areas today should be 
close to those of Tuesday. With the return of a weak sea 
breeze...areas near the coast should be a little cooler. A weak 
coastal eddy may bring the return of stratus to areas near the coast 
tonight into Thursday morning...mainly in the form of dense fog if 
it does return. For Thursday and Friday...a trough of low pressure 
will move southeastward through the Great Basin bringing some 
cooling and an increase in the marine layer...possibly enough to 
reach the lower coastal valleys. Even with the 
cooling...temperatures will remain above seasonal averages in most 
inland areas. 


Saturday and Sunday...for the weekend...broad high pressure aloft 
will bring higher temperatures again for inland areas with 
temperatures well above seasonal averages. With weak onshore flow at 
times...there may be some stratus at times near the coast with 
temperatures near the coast a little cooler than early this week. 


For Monday and Tuesday...a stronger trough of low pressure will move 
inland along the West Coast bring cooling to near seasonal 
averages...gusty winds...more clouds...and deepening of the marine 
layer. A little warmer on Wednesday as high pressure again builds 
aloft. 


&& 


Aviation... 
171900z...marine layer this afternoon was still non existant but 
should begin to recover tonight in response to a developing coastal 
eddy. This could bring a period of dense fog to ksan and other 
coastal airports before sunrise Thursday morning. Timing of any 
onset of fog will be difficult but most favored after midnight and 
before sunrise. Any fog should lift into a stratus layer Thursday 
morning before dissipating. 


Above the marine layer...except for some cirrus at or above 
fl250...a mostly clear sky with unrestricted visibilities will 
continue through Thursday. Horton 


&& 


Sgx watches/warnings/advisories... 
California...none. 
Pz...none. 


&& 


$$ 


Public...pg 
aviation/marine...Horton 


National Weather Service on the web at weather.Gov/sandiego