Weather

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Southeast Alaska forecast discussion 
National Weather Service Juneau Alaska 
625 am akdt Thursday Aug 28 2008 


Short term...a weak ridge of high pressure will continue to build 
over Southeast Alaska through the morning. This ridge will push east into 
Canada by this evening as a trough over the north central Gulf this 
morning drifts into the eastern Gulf and form a weak low pressure 
system. This low will continue southeast and move out of the area by 
Friday morning. The mean upper trough over the Gulf will drift east 
to be over the Panhandle by Friday morning and lift into Canada by 
the afternoon. As this trough moves east through today and tonight 
it will keep a deep onshore flow over the Panhandle. The onshore 
flow will allow light precipitation to persist over the northern areas 
through this evening but will begin to taper off as there will be 
an increase of offshore flow with the trough drifting southeast. This 
drying trend will continue into Friday as the offshore increases 
with the upper trough digging south and bringing drier air from the 
north. 


The southern areas will see periods of light rain this morning but 
with weak anti-cyclonic flow the precipitation will become less likely 
this afternoon but a chance will remain with the onshore flow. By 
this evening the low mentioned above will bring rain back into the 
southern areas tonight and continue into Friday morning. As the 
trough lifts pass the Panhandle the persistent rain will be scattered 
in the afternoon. 


As for winds...the building ridge is enhancing the winds in northern 
Lynn Canal to 25 knots this morning. Theses winds will slowly 
diminish through the late afternoon as the ridge pushes east into 
Canada. The rest of the area will see the winds increase to 15kt 
from the south and then diminish tonight. The coastal waters will 
see small craft conditions due to seas this morning but the seas 
will subside to around 5 feet through Friday from north to south. 


Long term...previous discussion issued 1258 PM akdt Wednesday Aug 27 
2008...long term...an upper trough over the East Gulf of Alaska Friday 
will move east into b.C. High pressure builds into the north Gulf late 
Friday night and Sat and shifts east over Southeast Alaska into Canada sun. The 
next low develops over the North Pacific Sat night and will deepen to 
995 mb west of the Queen Charlotte islands by Monday morning. 


GFS and ec seem to remain divided over the North Pacific low this weekend. 
Blended in the 27/12z GFS through early Sun morning then switched 
to the 27/00z ec for the rest of sun and beyond. Confidence in the 
models beyond sun remains low. 


Overall...light winds until Monday as North Pacific low moves towards the Queen 
Charlottes. As the low approaches the southeast Gulf...winds excepted to 
increase to a solid east-southeast small craft with possible min gale along 
the southeast outer waters. Cloud cover and rain will keep temperatures slightly 
below norm. The northern Panhandle will see drier conditions Sat 
behind the upper trough. 


&& 


Ajk watches/warnings/advisories... 
public...none. 
Marine...Small Craft Advisory for pkz012-041-042. 


&& 


$$ 


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