Weather

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Area forecast discussion 
southcentral and southwest Alaska 
500 am akdt Thursday Aug 28 2008 


Corrected date 


Analysis and upper levels... 


Upper level planetary trough extending from Kamchatka to the western 
Great Lakes persists this morning...with several embedded synoptic 
scale waves. Troughs in our portion of the hemisphere are located 
over the western Bering and akpen...with a closed upper low well 
north of the Bering Strait. At the surface...a broad area of low 
pressure remains over Mainland Alaska with a low pressure center in the 
northwestern Bering. Remnants of a decaying weather front are over 
southwest Alaska. 


Model discussion... 


Models are in excellent agreement through roughly 3 days. At that 
point a low from the North Pacific and the Bering low move to the 
vicinity of the akpen and Kodiak Island. A great deal of uncertainty 
exists about how energy from the Bering low jumps the akpen and 
merges with the North Pacific low. The ec...which has shown some 
consistency over the past several days...suddenly made an extreme 
adjustment with the 00z run and has been discounted. The forecast 
relies heavily on the GFS for the short term and the previous 00z run 
of the ec for the extended periods. 


Short term forecast... 


In the west...a weather front associated with the Bering low will 
reach the pribilofs today and the southwest coast Friday. Ahead of the 
front will be rain which will change to showers on the back side. 
Much of the Bering and Aleutians will have showers through Sat as the 
low becomes stationary in the central Bering. Showers will diminish 
Sunday as the low redevelops southeast of akpen. 


For southwest Alaska...showers can be expected across the area 
today...with some afternoon and evening thunderstorms near the Alaska and 
Aleutian ranges. By Friday conditions inland will dry as a ridge builds 
overhead. This will be shortlived along the coast as the Bering front 
moves inland with rain. Rain will diminish Sat morning and then 
showers will develop through sun as the low moves across the akpen. 


South and east of the Alaska Range...showery conditions will persist 
through tonight beneath a broad area of low pressure. Thermally 
induced low pressure will be the focus for a few afternoon and 
evening thunderstorms along the Alaska Range. By Friday the low pressure 
retreats to the east and showers will be limited to mountainous 
areas. This drying trend continues into Sat beneath a weak ridge. On 
Sunday the movement of the low into the Gulf means rain for the Gulf 
Coast with onshore flow. 


Long term forecast... 


A ridge builds over the Bering through midweek with areas of fog and 
drizzle. Southwest Alaska remains showery through Tuesday. At that point the 
low moves into the Gulf and drier northwest flow sets up. Southeast 
of the Alaska Range the low moves into the Gulf and makes the coast wet. 
Some showers can be expected inland into midweek. 


Aer/alu...watch/warning summary 
public...none 
marine...none 
fire weather...none 


Ds Aug 08 

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