887 
fxus66 kmtr 200004 
afdmtr 


Area forecast discussion 
National Weather Service San Francisco Bay area California 
300 PM PDT Sat Jul 19 2008 


Discussion...as of 3:00 PM PDT Saturday...satellite imagery shows 
the coastal stratus to be eroding from the north with some clearing 
north of Point Reyes. The eddies are still apparent in the Monterey 
Bay and near Point Piedras Blancas. Slight cooling is occurring 
across the northern half of the County Warning Area with slightly warmer temperatures 
across the south. The marine layer depth has been steadily rising 
through the day and is now around 1800 feet. The surface pressure 
gradients have increased as well with 3.1 mb between sfo and SAC... 
and 4.1 mb from acv to sfo. Even though the skies are clearing from 
the north...current thinking is that the clouds will reform over the 
ocean this evening with low clouds and fog spreading well inland 
again tonight as an upper level trough deepens just off the West 
Coast. This trough is expected to bring on a cooling trend over the 
next few days with an increasing marine layer and enhanced onshore 
flow. The upper trough is prognosticated to cut off into an upper low west 
of the northern California coast by Sunday night. This upper low then 
is forecast to move east across the extreme northern part of the 
state on Monday followed by weak ridging by the middle part of the 
week. Zonal flow across northern California will keep a typical 
Summer weather pattern for our district through the remainder of the 
forecast period. Near-normal temperatures with night and morning 
stratus episodes are expected. 


&& 


Aviation...as of 5:00 PM Saturday...sf Bay area...stratus is 
clearing off the coast as northerly gradients increase. Stratus 
expected to reform later tonight but will stay out of sfo and Oak 
until around 05z. Winds holding under 20 knots at sfo. Approaching 
upper trough will deepen the marine layer resulting in later 
burnoff Sunday. 


Monterey Bay area...clouds have stuck to southern mry Bay all 
day today and should stay in over mry and sns through Sunday morning. 


&& 


Mtr watches/warnings/advisories... 
... Bay 
pt Arena to Pigeon Point. 


$$ 


Public forecast: Anderson 
aviation/marine: Larry/west pi 


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