Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 261345

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
545 AM AKDT WED OCT 26 2016


Upper air...
An upper level ridge extending north-south along the Alcan border
will build into a closed high center over the northern Yukon
Territory by 4 pm this afternoon which will expand eastward into
the northwestern Northwest Territories by Thursday afternoon. An
upper low centered 625 nm west of Point Hope will move to 700 nm
west of Point Hope by 4 pm Thursday while gradually weakening,
then open up into a trough along 155E longitude by midnight
Thursday night. A short wave trough extending from the upper low
center southeastward to the eastern Aleutians will weaken as it
moves northeastward across the northern Alaska mainland, then
exits into the Beaufort Sea by 6 pm Saturday. This short wave will
cut into the upper level high, with another ridge rebuilding and
moving eastward as the short wave trough exits out of Alaska. This
ridge will become very high in amplitude as it moves to 145W
longitude by 4 pm Saturday. Current operational models appears to
be in good agreement on the handling of these features through 4
pm Saturday. Another short wave trough will move into the far
western Bering Sea by Thursday afternoon, developing into an upper
low center 500 nm west southwest of St Matthew Island. The low
will move northward on a looping trajectory to around 500 nm west
of St Lawrence Island by Saturday afternoon. Another short wave
tracking eastward across the Aleutians will deepen into an upper
low centered 400 nm southwest of the Pribilofs by Saturday
evening, then move into outer Bristol Bay by Sunday evening.

An occluded front extending from Wainwright southward across the
western interior will continue to weaken today with little further
eastward movement. Winds across the west coast areas have
diminished considerably after the frontal passage. A 965 mb low
center will move into the far western Bering Sea by Thursday
evening, to be centered about 600 nm west southwest of St Lawrence
Island. The associated weather front will move into the Bering
Sea. By Thursday evening the front will extend from the low center
to 200 nm south of St Lawrence Island, then`curving southward to
neat St Matthew Island and then south southwestward across the
Aleutians and into the Pacific Ocean. There continues to be
differences between the models on the development of a surface
low along the front. GFS and NAM develop a weak low center 100-200
nm south southwest of the Pribilofs by midnight Thursday night,
while the ECMWF develops a substantially deeper low near 50N/175W
by midnight Thursday night. By early Friday evening, the ECMWF
rapidly deepens the low down to a 945 mb center just southwest of
St Lawrence Island while the GFS just moves the front northward
and eastward without any significant low developing on the front.
The Canadian model develops a 962 mb low just east of the
Pribilofs as the same time. While the models differ on the driving
forces, all suggest the likelihood of full gale to storm force
south to southeast winds across the northern Bering Sea, Norton
Sound, Kotzebue Sound, and the Chukchi Sea. The strong winds could
develop as early as late Thursday night over the northern Bering
Sea and St Lawrence Island, and by Friday morning across Norton
Sound, and by Friday afternoon over Kotzebue Sound and The Chukchi

Coastal Hazard Potential Days 3 and 4...
The models still differ on the driving forces, but indicate
a likelihood of high surf conditions and possibly coastal
flooding along west coast areas susceptible to high surf and
coastal flooding with strong south to southeast Winds. Current
GFS-based guidance indicates potential for a maximum storm surge
of 4 feet or a little more from the eastern shore of Norton Sound
to the Bering Strait coast Saturday afternoon and evening, with an
earlier period of 3 to 4 foot surge from the Nome area to the
Bering Strait Friday afternoon and evening. Areas along the Yukon
Delta coast could see a maximum surge of around 3.5 to 4 feet from
around mid day Saturday into Saturday evening. A maximum surge of
around 4 feet might be enough to create potential for some minor
coastal flooding in areas near Scammon Bay. Due to the differences
in current model solutions, subsequent model runs will need to be
evaluated before issuance of any new coastal flood watches or
high surf advisories.



Small Craft Advisory for PKZ210-PKZ220-PKZ225.


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