305 
fxus66 kmtr 030552 
afdmtr 


Area forecast discussion 
National Weather Service San Francisco Bay area California 
952 PM PST Tuesday Dec 2 2008 


Discussion...as of 9:55 PM PST Tuesday...mainly clear skies across 
the district this evening with the exception of a few patches of 
low clouds here and there. Patchy low clouds and fog located in the 
inland valleys may linger through the night while patches over the 
hills will scatter out overnight. The Fort Ord profiler shows a 
fairly well mixed layer with no inversion to speak of at this hour. 
Anticipate skies to remain clear through the most of the night. 
However lingering low level moisture may allow patchy low clouds and 
fog to form during the early morning hours on Wednesday. 


Daytime temperature finished off the day as much as 11 degrees warmer 
than yesterday across the northern half of the County Warning Area and along the 
coast while inland temperatures ended the day up to 16 degrees cooler 
than yesterday. 


After thinking that the GFS and the European model (ecmwf) had finally come to a 
consensus as to how this next system was going to evolve todays 
runs reminded ME how unpredictable upper level systems can be. 
The upper level low that is being debated will develop into a cut 
off low just off the Pacific northwest coast on Wednesday and move 
south off the California coast Wednesday night and Thursday. By 
Thursday afternoon model solutions begin to deviate with the GFS 
driving the low further south. The GFS takes the low to approx 
129w/26n by Friday and allows the low to meander west of the Baja California 
coast through the weekend. Meanwhile the European model (ecmwf) turns the low toward 
the north then east near 125w/30n Thursday evening and takes the low 
into Southern California bringing rain chances to our region Saturday 
and Sunday. Low confidence in the extended forecast at this time. 
Will monitor future runs to make any changes to the current 
forecast. 


&& 


Aviation...as of 9:52 PM PST Tuesday...dense fog is already 
occurring in parts of the North Bay as ksts has been hitting 1/4 
mile for the past several hours. The sf Bay area airports will also 
likely see intermittent ceilings at or below 1000 feet especially after 
midnight. Farther south...the Monterey Bay region is less likely to 
see widespread low clouds and fog being farther removed from the 
Central Valley Tule fog...but there could be intermittent ceilings 
around 1000 feet after midnight at ksns as well as at kmry. 


&& 


Mtr watches/warnings/advisories... 
... Arena to pt Piedras Blancas 20-60 nm. 
Pt Arena to pt Reyes 0-20 nm. 
Pt pinos to pt Piedras Blancas 0-20 nm. 


&& 


$$ 


Public forecast: CW 
aviation/marine: ssa 


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