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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska 
511 am akdt Friday Mar 19 2010 


Discussion... 
aloft...ridge of high pressure from western Canada to the northern 
Beaufort Sea will develop into a closed high circulation over the 
Beaufort Sea over the next 24 hours while long wave trough holds 
its own over far east Russia and the southwest Bering Sea. A short 
wave trough in the Gulf of Alaska will move north to the Alaska 
Range by 10 am Sat and then dissipate. Short wave trough from the 
Gulf of Anadyr to Saint Matthew Island to the pribilofs will move 
to the Bering Strait to Nunivak Island Sat am and then dissipate. 
Shortwave trough over Banks Island rotating south to eastern 
Arctic coast 10pm Friday then continuing south to Dawson 4pm Sat. 


Surface...weakening occlusion from Gulf of Anadyr to just east of 
the pribilofs will drift north to extend from the Bering Strait 
to Nunivak Island 4am Sat then dissipate. 1004 mb low in Gulf of 
Alaska with occlusion along coast...low dissipating over Kenai 
Peninsula 4am Sat while occlusion reaches Alaska Range very weak. 
High pressure center of 1040 mb near 80 north latitude moving slowly 
south through Sat night. 


Models...agree fairly well at surface and aloft in short term. On 
Sunday and Monday both GFS and NAM are consistent in building a 
ridge over the Bering Sea while causing the short wave trough 
moving south from the Arctic coast to Dawson to expand over 
interior Alaska toward Bristol Bay. 


Medium term...models and model ensembles are in overall good 
agreement with the large scale features. The NCEP rmop values 
stay below average across the state while high rmop values are 
indicated for a strong ridge over the Beaufort and northern 
chukchi seas during this time. Overall temperatures will not stray too 
far from seasonal averages and precipitation will remain none or very 
little. 


North Slope...easterly winds picking up today as high pressure in 
the high Arctic drifts south behind the short wave trough moving 
over the eastern coast. Flurries and fog this morning will give 
way to blowing snow this afternoon from Wainwright east. Winds may 
slacken a bit Monday as the high pressure builds south and the 
occlusion over the southern interior dissipates. 


Western Alaska...old occlusion over zone 213 will spread a little 
snow east over the Bering Strait...Yukon Delta...Seward 
Peninsula and Norton Sound through Saturday. Expect up to an inch 
accumulation over Saint Lawrence Island...Bering Strait and Yukon 
Delta. As system moves farther east dynamics will weaken and 
snowfall will be minimal. Winds over marine zone 210 decreasing 
this morning. 


Central/eastern interior...occlusion along Gulf of Alaska coast 
will spread clouds north today and bring a chance of snow tonight 
and Saturday to zones 225 226 and southern 224. Expect only 
flurries at times for zones 222 223 and 221 Friday night into 
Sunday. East winds picking up Saturday over the northern and 
central interior as the short wave trough moves slowly south and 
then high temperatures dropping some through weekend with the cooler air 
behind it. 


&& 


Afg watches/warnings/advisories... 
brisk Wind Advisory for pkz210-pkz220-pkz225-pkz230-pkz235- 
pkz240-pkz245. 
&& 


$$ 


Jl Mar 10 

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