Blizzard in Alaska, February 25 to 26, 2017

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
311 PM AKST Fri Feb 24 2017

.DISCUSSION...
Another busy weather day across Northern Alaska with the main
forecast concern being the numerous winter weather hazards across
our area of responsibility. The majority of winter storm watches
have been upgraded to winter storms warnings, while a few were
converted to winter winter advisories, which will be elaborated
on below. The 24/12Z model suite is in good agreement throughout
the forecast period, but there are some slight differences in
movement of low features beyond 00Z Wednesday across the Gulf of
Alaska and over the high Arctic.

Aloft...An upper level shortwave continues to push east over the
Eastern Interior flattening the upper level ridge and will move
into western Canada tonight. A second weaker shortwave currently
over northwest Alaska will quickly drop southeast over the
Interior tonight and into western Canada by Saturday morning. An
upper level over the Western Bering will lift north over the
Chukotsk Peninsula and Bering Strait Saturday, then will move east
along the Brooks Range through late Sunday. An upper level trough
will swing south over the forecast area Sunday night into late
Monday evening. Strong cold air advection will follow this upper
level trough with H850 temperatures dropping 10C to 15C by Tuesday
morning. The coldest H850 temperatures colder than -25C will be
contained north of the Brooks Range with the rest of the area
seeing -18C to -22C.

Surface...A 1012 mb low over Point Thomson will move east and into the
Northwest Territories this evening. A weak low northwest of Saint
Lawrence Island will weaken as it moves towards the Chukotsk
Peninsula this evening. A trough of low pressure extending from
the weak Bering Sea low east over the Brooks Range and eastern
Arctic Coast will remain in place through Saturday morning. A 969
mb low over the western Bering Sea will track north towards the
Chukotsk Peninsula tonight, then weaken as it expands eastward
over the old surface trough in the Brooks Range and Eastern
Beaufort Sea Saturday and Sunday. A strong 1041 mb ridge of high
pressure will remain entrenched over the high Arctic, while
another 1045 mb ridge of high pressure persists over the Northern
Pacific and Gulf of Alaska through the weekend.

Western Interior and West Coast...The majority of Winter storm
watches have been upgraded to Winter Storm Warnings, with the
exception of zone 216 where a Winter Weather Advisory was issued.
Existing warnings and advisories pertaining to snow and blowing
snow looks to be in great shape. Another round of heavy snow is
expected across Western Alaska. Snow will redevelop over the Yukon
Delta and Saint Lawrence Island overnight and will spread north
towards the western Brooks Range through tomorrow afternoon. Most
areas will see 5 to 13 inches, except for the Kobuk and Noatak
Valleys and the western Brooks Range where another foot or more
snow is forecast. Winds are also expected to increase and cause
problems with blowing snow to create low visibilities. For now,
given the nature of the wet and heavy snow, thinking that
visibilities will be one half mile at times. Snow will diminish
late Saturday night and Sunday morning from south to north. A
cooling trend towards below normal temperatures will start early
next week with below normal temperatures persisting for most of
next week.

Arctic Coast and Brooks Range...A blizzard watch has been issued
for zone 201 (western Arctic Coast) with a pair of winter weather
advisories for the Northern Brooks Range for blowing snow through
passes. Another round of snow, 4 to 8 inches total, is expected
along the western Arctic Coast. This new snow coupled with strong
east winds gusting up to 50 mph will likely create a weather
scenario for blizzard conditions. The ongoing winter weather
advisories for zones 202 and 203 (Northern Arctic Coast and
Central Beaufort Sea Coast) will likely be allowed to expire at
its expiration given that conditons have improved.

Eastern and Central Interior...Another round of heavy snow is on
its way and break out your shovels and snow blowers once again!
Winter Storm Watches have been upgraded to Winter Storm Warnings
for zones 218, 220, and 222 and have included mention of blowing
snow to all warnings, except for zone 222. Southwest winds will be
the strongest of highway summits and over higher terrain and will
create blowing and drifting snow and low visibility. In warned
areas, 6 to 12 inches is forecast, heaviest in the upslope areas.
In the Fairbanks areas, could see 7 to 8 inches with higher
amounts north and east of Fairbanks. Winter Weather Advisories
were issued for zones 221, 223, and 225 where 4 to 9 inches are
forecast. Snow will diminish from west to east Sunday. Cold
temperatures will return early next week with colder than normal
temperatures persisting through late next week.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Blizzard Watch for AKZ201.

Winter Storm Warning for AKZ207-AKZ208-AKZ209-AKZ210-AKZ211-
AKZ212-AKZ213-AKZ217-AKZ218-AKZ219-AKZ220-AKZ222.

Winter Weather Advisory for AKZ202-AKZ203-AKZ205-AKZ206-AKZ214-
AKZ215-AKZ216-AKZ221-AKZ223-AKZ225.

Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ200-PKZ215-PKZ220-PKZ225-PKZ230-
PKZ235.
&&

LTH FEB 17