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Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
146 PM akst Thu Dec 8 2016

Synopsis...
aloft...
the long wave pattern consists of a ridge over the eastern Bering
Sea and northern Alaska with a trough of southern Alaska and the
Gulf of Alaska and another trough over the Sea of Okhotsk and
Kamchatka. This pattern will persist into Fri and then evolve with
a high building over northern Alaska on the weekend.

The ridge will retreat south Mon and then rebuild over northern
Alaska later in the week.

This pattern will keep generally clear conditions over northern
Alaska through the weekend excepting clouds and flurries in the
extreme southeast interior today through Fri...and another batch
of clouds and flurries over the eastern North Slope from Fri PM
through Sat PM. May see clouds and snow over the West Coast south
of the Bering Strait late sun.

Temperatures over interior valleys will remain cold through the
weekend...while West Coast and Arctic coast will warm to near
normal by the weekend.

A short wave trough extending from Bethel to Denali to Chicken
will move to Bethel to Denali to Northway by 3pm Fri then drift
south of the Alaska Range. A patch of stratus and flurries south
of this trough over the upper Tanana Valley and over the yk Delta
will persist through Fri then dissipate. Strong east winds at 925
mb just north of this trough will persist through Fri then weaken
Fri night as the trough weakens. These winds will surface over
ridge tops and in channeled valleys draining to the west.

A second short wave trough in the high Arctic will move south to
lie along the eastern North Slope Fri PM and then dissipating over
the eastern Brooks range Sat. Expect mid to low level clouds and
light snow with this.

Surface...
a 1055 mb high over northwest Canada with a ridge stretching west over
the Brooks range will weaken slowly through sun. Skies will
generally remain clear under the high with continued cold air in
calm valleys such as the Yukon Flats...the Kanuti Flats...and
with slight moderation in other valleys of the southern interior
where east winds mix out the coldest air.

An occluded front that has moved aloft from Gulkana to Northway
will move to Talkeetna to Northway by 3am Fri and then dissipate
Fri PM. There are clouds and light snow associated with this that
will spread west to the Denali area tonight.

The surface gradient between the high and the front are causing east
winds 10 to 20 mph across the southern interior and West Coast.
This will keep the southern interior from getting as cold as the
northern interior. Will see stronger much stronger gusts in
channeled areas and ridge tops exposed to east winds through Fri.
Winds will decrease on the weekend as the weather front
dissipates.

A weather front moving north into the central Bering Sea sun will
move to the northern Bering Sea Sun night and Mon. Expect
increased east winds and a chance of snow along the West Coast
south of the Bering Strait late sun into Mon.

&&

Discussion...
models initialize well at 500 mb and show similar solutions through
Sat then start to see differences sun with the short wave trough
over the northern Bering Sea. Prefer the GFS solution which shows
a stronger short wave than the other models since it has a strong
short wave moving out of a deep long wave trough over Kamchatka
and and northwest Pacific.

At the surface models initialize too weak at 18z on the high
pressure over the Brooks range and NE interior. Expect surface
pressures to weaken more slowly tonight than models show and will
keep a tighter surface gradient and slightly stronger winds than
models show over the interior and West Coast through tonight.

Coastal hazard potential days 3 and 4...none.

&&

Afg watches/warnings/advisories...
Winter Weather Advisory for akz219.

Heavy freezing spray warning for pkz210-pkz225.

Brisk Wind Advisory for pkz200.

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