Blizzard in Alaska, December 17 to 19, 2017

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
414 AM AKST Sun Dec 17 2017

.DISCUSSION...

Models...There continues to be good run to run continuity.
Solutions remain similar in the short tern and there is better
agreement out to around 72 hours. Current solutions initialized
well against the 17/06Z surface analysis. Will go with the SREF
for precipitation for the short term.

Aloft...The 505 dam low that was over Nunivak Island yesterday is
now in the Northern Gulf of Alaska at 515 dam, and a 512 dam low
has developed over the Upper Kuskokwim River Valley. The trough
will move slowly east to be over the AlCan border late this
evening as it weakens. Ridging lies over 170W this morning and
will move over the West Coast tonight. It will continue east with
the axis lying from Seward to Nenana to Wainwright Monday evening,
then over the AlCan border and extending northwest across the
Arctic by Tuesday afternoon. A 492 dam low is moving into the
Western Bering Sea this morning and to the northwestern Gulf of
Anadyr by Tuesday morning at 490 dam. A strong shortwave
associated with the low will move to the Dateline by Monday
morning, the Eastern Bering Sea Monday afternoon, and over the
West Coast Monday night. The shortwave will continue to move
northeast across the state with southwest flow developing over
most of mainland Alaska Tuesday. At 850 hpa...Cooling trend
continues today with temperatures falling to around -10 over the
forecast area. Low moving through the Bering Sea will produce a
weak warming trend south of the Bering Strait and west of McGrath
Monday, with warmer air pushing north and east as through Tuesday.

Surface...High pressure remains over the Arctic as it extends
southeast from a 1032 mb high near 78N 165E to south of Banks
Island and will persist into Monday before it is pushed just
offshore by the approaching low pressure system and troughing
develops over the Arctic Coast. A broad area of low pressure will
remain over most of the state. A 978 mb low pressure system that
was near Nunivak Island is now just east of Kodiak City and will
move east across the Gulf of Alaska. A 996 mb low near Kotzebue
Sound will weaken and either dissipate or merge with the
approaching system in the Chukchi Sea. Several minor lows are
floating around the interior. Weak ridging south of the Bering
Strait will move over the southwest mainland tonight, then pulls
south into the Gulf. A bubble high will develop over the Upper
Yukon Flats tonight and dissipate Monday evening. A 960 mb low
is moving into the Western Bering Sea this morning with a front
moving to the Central Bering Sea and Central Aleutians this
evening. The low will slowly move east in the Northern Bering Sea
and the front will move to St Lawrence Island Monday afternoon,
and to the West Coast by Monday evening. The front will bring
some warmer air with it and could produce freezing rain in the
lower Yukon Delta and on St Lawrence Island Monday.

Arctic Coast and Brooks Range...Cloudy, occasional light snow or
flurries, fog, Blowing snow. The persistent northeast and east
winds of 20 to 30 mph will be diminishing today to 10 to 20 mph.
Expect improving conditions as the winds diminish. Temperatures
will continue to slowly cool.

West Coast and Western Interior...Cloudy conditions will continue
today with a few breaks during the day. A few flurries through the
day or a period of snow. Conditions will improve a bit before the
next system arrives tomorrow. Zones 207, 209, and 213 will
require Blizzard Warnings, with Winter Storm Warnings for zones
208, 211, 212, 214, 215, 216, and 217. Snowfall amounts will
range up to 20 inches with the heaviest amounts in the Upper
Kobuk, Upper Noatak, Nulato Hills, and Bendeleben Mountains. Heavy
snow will move to St Lawrence Island around midnight, and move to
the West Coast by morning. Strong southeast to south winds will
arrive with the snow or shortly after with winds 30 to 40 mph
gusting to 65 mph on St Lawrence Island and the Bering Strait
coast. The strong winds will move to the coast with near Blizzard
conditions developing in some areas and Blizzard conditions
developing in Kotzebue Sound. As the front moves inland there is a
chance of Freezing Rain in the lower Yukon Delta and on St
Lawrence Island.

Central and Eastern Interior...Mostly cloudy with light snow and
flurries today. Some patchy fog this morning. Snow accumulations
less than 2 inches. Light winds. Temperatures slightly cooler.

&&

Coastal Hazard Potential Days 3 and 4...A low moving northeast
into the Gulf of Anadyr Wednesday night and Thursday will produce
strong south winds to St Lawrence Island and the Bering Strait and
may help break up the ice pack.

&&

Extended Forecast for days 4 to 7...Ridging setting up over the
Southeast Panhandle and Southeast Interior will pull some slightly
warmer air north over the forecast area.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

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

Blizzard Warning for AKZ207-AKZ209-AKZ213.

Heavy Freezing Spray Warning for PKZ210-PKZ220.

Small Craft Advisory for PKZ220.

Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ225-PKZ230.

&&

SDB DEC 17