Blizzard and Ice Storm in Alaska, December 28 to 31, 2016

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
509 AM AKST Wed Dec 28 2016

.SYNOPSIS...
Aloft...Northern Alaska is now entering into a progressive
pattern where a series of high energy short wave troughs will move
east across Alaska at least through the weekend. This will bring
us into a very active pattern from Wed night through the weekend.

A low aloft with an attendant surface low now located near
Buckland will move to Bettles by 3pm Wed...to Arctic Village by
3am Thu and then east. A short wave trough extending south from
this low to Anvik will move to Bettles to Denali by 3pm Wed...to
Arctic Village to Tok by 3am Thu...and east of the Alcan Border by
15Z Thu. Light snow along and east of the trough and low will
diminish to flurries west of the trough. Expect 1-2 inches of snow
across the Interior with this feature...except up to 4 inches
along the Alaska Range where low level upslope will enhance the
snow.

Surface...
A 999 mb low near Buckland that is vertically stacked under the
low aloft mentioned above will move to Bettles as a 1015 mb low by
3pm Wed...to Arctic Village as a 1020 mb low by 3am thu and then
dissipate. See low aloft mentioned above for associated weather.

A 966 mb low 300 nm west of Shemya is expected to deepen rapidly
and and move to 400 nm northwest of Shemya as a 938 mb low by 3pm
Wed...then move inland to near Anadyr as a 953 mb low by 3pm
Thu...and to near Wrangel Island as a 980 mb low by 3pm Fri.
Will see strong southeast winds developing over the northern Bering
Sea and southern Chukchi Sea tonight becoming southwest Late
Thursday and Friday around this low. This could lead to Coastal
Flood issues for the West Coast from the Yukon Delta to the Bering
Strait Thu night through Sat am. Due to the strength of the winds
and the long fetch which is expected to push water a large volume
of water into the northern Bering this will likely push water up
under the ice that is now in place. Will likely issue as Coastal
Flood Watch for the Coast from the Yukon Delta to the Bering
Strait and for St Lawrence Island for Thu night through Sat am
for a surge of 4 to 8 ft.

North of the Bering Strait there is much uncertainty on how much
water will push north of the Bering Strait and under the ice...but
there is a chance of a surge there from Fri afternoon through Sat
am along the Chukchi Sea Coast. Will assess this further as we get
closer to the event.

A strong warm front stretches east of this low and will move to
Cape Navarin to the southeast Bering Sea by 3pm Wed...to
Provideniya to the Yukon Delta by 3am Thu...to Point Lay to
Minchumina by 3pm Thu...and to Prudhoe Bay to Dawson by 3am Fri.
Will see southeast winds 40-50 kt along this front along the
coasts and 20 to 30 kt inland. Expect snow to begin ahead of
the warm front with Blizzard conditions along the coast and near
blizzard conditions inland. Snow will change to rain or freezing
rain along and south of the warm front over zones 213 and 214
tonight. As the warm front moves inland Thu could see freezing
rain south of a Bering Strait to McGrath line in Zones 211 212 213
214 215 216 227.

A trailing cold front will move to Provideniya to St Matthew
island by 3am Thu...to Point Hope to Bethel by 3pm Thu...and to
Prudhoe Bay to Denali by 3am Fri...and along the Alcan Border by
noon Fri. Southwest winds of 25 to 35 kt are expected with the
cold front and should spread inland across the Interior as the
cold advection mixes the strong winds down to the surface along the
front. This will cause near Blizzard conditions across the
Interior as well. Snow will taper off west of the cold front.
Expect a storm total of 6 to 12 inches of snow by Fri across the
West Coast and Interior with this system from the Brooks range
south. Upslope areas such as south slopes of the Brooks range
could see higher amounts.

A trailing low developing in the southwest Bering Sea Thu Pm will
move to 300 nm west of St Matthew Island by 3am Fri as a 972 Mb
Low and to the southern Chukchi Sea as a 982 mb low by 3pm Fri.
Expect southwest winds to 50 mph along with more snow and another
possible Blizzard for the West Coast Fri. These strong southwest
winds will give the highest change of flooding along the coast
Fri.

&&

.DISCUSSION...
At 500 mb models initialize well and show similar solutions through
the weekend and the long wave pattern. Models differ some on
details of speed and strength of short waves and attendant surface
features. Since the all the high energy features are coming from
the Eastern Russia and the NW Pacific outside the NAM domain and
are handled similarly by the GFS and ECMF...will use the GFS
solution through Fri.

Coastal Hazard Potential Days 3 and 4...
Coastal Flooding possible for the West Coast from the Yukon Delta
to the Bering Strait Thu night through Sat am. Due to the strength
of the winds and the long fetch which is expected to push water a
large volume of water into the northern Bering this will likely
push water up under the ice that is now in place. Will likely
issue as Coastal Flood Watch for the Coast from the Yukon Delta to
the Bering Strait and for St Lawrence Island for Thu night through
Sat am for a surge of 4 to 8 ft. The second storm is expected to
bring southwest winds to 50 mph to the the West Coast Fri. These
strong southwest winds will give the highest change of flooding
along the coast Fri.

North of the Bering Strait there is much uncertainty on how much
water will push north of the Bering Strait and under the ice...but
there is a chance of a surge there from Fri afternoon through Sat
am along the Chukchi Sea Coast. Will assess this further as we get
closer to the event.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch for AKZ218-AKZ219-AKZ220-AKZ221-AKZ222-AKZ225.

Winter Storm Warning for AKZ205-AKZ206-AKZ208-AKZ210-AKZ211-
AKZ212-AKZ214-AKZ215-AKZ216-AKZ217-AKZ227.

Blizzard Warning for AKZ201-AKZ207-AKZ209-AKZ213.

Winter Weather Advisory for AKZ202-AKZ213.

Heavy Freezing Spray Warning for PKZ210.

Small Craft Advisory for PKZ210.

Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ220-PKZ225.
&&

JB DEC 16