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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska 
327 PM akst Thursday Nov 20 2008 


Synopsis... 
the long wave pattern consists of a trough over Mainland Alaska 
with a ridge over western Canada and another ridge over the 
eastern Bering and another trough over the northwest Pacific/Kamchatka. 
The trough over Mainland Alaska will deepen through the weekend 
as short wave energy from the northwest Pacific undercuts the 
eastern Bering ridge and feeds into the Mainland Alaska trough. 
This should keep temperatures below normal into the weekend. 


High pressure over the Arctic coast will build north of the coast 
tonight and then persist there into the weekend. This will cause 
winds along the Arctic coast to turn northeast tonight and persist 
through the weekend, causing flurries and fog to increase due to 
the onshore flow. 


A ridge from this high south over the West Coast of Alaska will 
weaken slowly through Friday. This will cause weak northeast winds 
to increase there on Friday. 


A warm front aloft from Glennallen to Fort Yukon will move to 
Denali to Arctic Village by 3am Friday...by 3pm Friday from minchumina 
to anaktuvuk...and then dissipating. Snow will spread northwest 
with this front with heavier overrunning snow east of the front. 


A trough aloft trailing this front that is now south of the Alaska 
Range will move along the Alaska Range by 3am Friday...to minchumina 
to Eagle by 3pm Friday...to Galena to Arctic Village by 3am Sat...then 
dissipating. Most of the snow will occur between the warm front 
and this trailing trough aloft, with the snow tapering off south 
of the trough. Expect 1-2 inches of snow tonight over the eastern 
interior with these features and another 1-2 inches on Friday. The 
heaviest amounts will be east of pabi-palr. Storm totals will be 
less than 4 inches except in zones 226 and possibly 218. Strong 
east winds will develop over the hills of the interior ahead of 
the trough aloft tonight then decrease south of the trough. 
Expect east winds 20-30 miles per hour over hills along with low visibility 
in blowing snow. 


Another significant short wave will move north to the eastern 
Alaska Range sun bringing another chance of snow with it. 


&& 


Discussion... 
models initialize well and show similar solutions at the surface 
and aloft. Models differ on snow fall in the interior. None of the 
models spread the snow northwest quick enough today, but by 
tonight location of snow fall looks more reasonable. The NAM 
appears to do better with snowfall/precipitation amounts. 


Quick scat winds along the West Coast over chukchi and northern Bering 
appear to be ice affected and way over do wind speeds. 


850 mb temperatures are less than -18c across the forecast area 
now but will see weak warm air advection over the southeast interior through Friday 
and more moderate warm air advection over the eastern interior Sat under weak 
south flow aloft. 


Coastal hazard potential days 3 and 4...none 


&& 


Afg watches/warnings/advisories... 
heavy freezing spray warning for pkz210-pkz220-pkz225. 


Small Craft Advisory for pkz220-pkz225. 


Gale Warning for pkz210. 
&& 


$$ 


Jb Nov 08 

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