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Area forecast discussion 
southcentral and southwest Alaska 
500 am akdt Sat Jul 5 2008 


Analysis and upper levels...this morning we have a double barrel low 
scenario in the Gulf of Alaska as the Bering trough has finally 
shifted south and east. A thermal trough draped along the Alaska 
Range will strengthen this afternoon aiding widespread convection. 
The GFS was used to freshen up the forecast this morning as its 
performance and consistency has been stellar as of late. 


Short term forecast...a shortwave currently near the eastern end of 
Prince William Sound will continue to move west today. A solid band 
of showers associated with this wave will move along the coast with 
at least some clearing in its wake by this afternoon. Another wave 
will move in from the Yukon later today and ride along the thermal 
trough. Partly cloudy skies along and north of the trough will lead 
to rapid destabilization. Numerous thunderstorms are expected from 
the Copper River basin...stretching along the Alaska Range to the 
Kuskokwim Delta and as far south as the Anchorage bowl. Stability 
indices are certainly sufficient for strong thunderstorms...with a 
lack of strong shear the only deterring factor to a few potentially 
severe storms. Yet another wave takes a similar path on Sunday...but 
with plenty of convective debris hanging around...a more stable, 
stratiform rain event may take shape for much of southcentral. Fewer 
thunderstorms on Sunday will be due to the fact that the thermal 
trough will be pushed further north. The exception will be found in 
the Kuskokwim valley where the front will remain firmly entrenched 
for one more day. 


Further west...northerly flow will dominate the Bering behind the 
departing low. Showers will continue along the Bering side of the 
akpenn and eastern Aleutians with the ever present fog maintaining 
its grasp on the area. High pressure in the western Bering builds 
into the central Bering ahead of a strong front poised to drop south 
on Tuesday. 


Long term forecast...the low in the southern Gulf becomes vertically 
stacked by Monday and thus will be a slow mover. This means periodic 
waves approaching southcentral from the east prompting scattered to 
numerous shower activity. By mid-week...the Mainland sees ridging 
in-between the departing low in the Yukon and a strong low dropping 
into the central Bering. Models have been more consistent over the 
past couple of runs dropping the low into the central Bering bringing 
plenty of rain...wind and cooler temperatures. Questions arise by weeks end 
as to if the low drops south of the Aleutian chain or drift east. 
Thankfully we are talking about the end of next week...with plenty of 
time for the models to come to a consensus. 


Aer/alu...watch/warning summary 
public...none. 
Marine...none. 
Fire weather...none. 


Jca 

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