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fxus66 keka 071045 cca 
afdeka 


Area forecast discussion...corrected 
National Weather Service Eureka California 
345 am PDT Thursday Aug 7 2008 


Synopsis...an upper level trough will approach from the Gulf of 
Alaska on Friday and reinforce the marine layer. Expect patchy fog 
and drizzle along the Redwood coast through the week with dry 
conditions elsewhere. A weak cold front will push through the region 
Saturday bringing an end to the drizzle. Dry weather will prevail 
across northwest California into next week. 
&& 


Short term...WV Sat imagery shows drier air advecting into northwest California on 
southwest flow aloft. Upper level low offshore will continue to 
weaken as it ejects NE in response to stronger upper low moving east-southeast 
from Gulf of Alaska. As the first low passes north of County Warning Area...isolated convection 
remains possible this afternoon. Although most activity will remain 
north and east of County Warning Area over Siskiyou County...cannot rule out a cell or two 
developing over the Trinity Alps before moisture exits region. The 
marine layer will deepen by tonight as the upper level trough from 
the Gulf of Alaska approaches. This will produce patchy dz and fog along 
the Redwood coast by Friday morning. The upper level low will move 
inland Sat pushing a weakening front through County Warning Area. High pressure will 
build into the region in the wake of the front leading to a warming 
and drying trend across the region into next week. A thermal trough 
will develop over central California resulting in east-NE nocturnal winds and 
poor overnight humidity recoveries over the ridges. The ridge shifts 
east by middle week as an upper level trough deepens over the NE 
Pacific. Long range guidance diverges in regards to this trough. The 
GFS remains deeper with the trough but moves it into the Pacific northwest 
Wednesday...while the European model (ecmwf) develops a cutoff low off the California/or coast. 
Will maintain near normal temperatures and dry conditions through the 
extended. British Columbia 
&& 


Fire weather...drier air filtering into the region will 
diminish the threat of convection across most of the district today. 
A weak upper level disturbance will move north of the area today with 
some instability around the Trinity Alps this afternoon. Dry SW flow 
will likely keep most of the storms north and east of the region but 
maintained schc thunderstorms over Trinity Alps this afternoon just in case. 
Conditions will dry out and stabilize even more on Friday and 
Saturday as a new upper trough drops south from the Gulf of Alaska. British Columbia 
&& 


Aviation...the marine layer depth is around 1500 feet this 
morning...as another overnight round of LIFR stratus continues along 
the coast. Visibilities at coastal airfields overnight will generally 
remain MVFR to VFR...though patchy IFR fog could develop around 
daybreak. With an upper level trough offshore beginning to influence 
the West Coast...its possible that cooler air aloft could help 
promote better stratus clearing late this afternoon. Most locations 
however will once again see ceilings rising to around 008 to 011 during 
the afternoon hours. Interior locations will see some local Ridgetop 
cumulus development...especially over the Siskiyous and northern 
Trinity Alps. Conditions are expected to otherwise remain VFR with 
passing middle-level clouds. Alm 
&& 


Marine...light winds and mixed S-SW and northwest swell at around 2 to 4 
feet will continue through early Saturday morning over the waters. 
Northerly winds will increase behind a weak frontal passage late 
Friday into Saturday...as east Pacific high once again rebuilds into 
the region. Offshore waters will see advisory conditions by Saturday 
afternoon with gale force gusts possible Saturday night into Sunday. 
At the moment...confidence of the extent and strength of gusts is 
low so have held off with a gale watch. Waters within 10 nm will see 
low end advisory winds during the same time period with increasing 
westerly fresh swell. Alm 
&& 


Eka watches/warnings/advisories...none. 
&& 


$$ 


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