FXAK69 PAFG 271532
Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
632 AM AKST Mon Jan 27 2020
A very cold airmass will remain over Northern Alaska for the
coming week. Very cold wind chills occuring over the Eastern North
Slope, through Brooks Range and Alaska Range passes, and along the
much of the West Coast, and over the Steese and Elliott Highway
Summits will persist through mid-week and possibly through late in
the week. Temperatures will range from 30s and 40s below over the
Western Interior and North Slope, to the teens and 20s below in
cloudy or windy areas and along the West Coast and in cloudy or
windy areas of the Eastern Interior and Eastern North Slope.
There will be pockets of 50s below in the Koyukuk Valley and the
inland North Slope where conditions are clear and not windy.
Areas of snow will move north over the Eastern Interior and
Eastern North Slope through Wed, with temps in the teens and and
20s below when it is cloudy, then dropping into the 30s and 40s
below during the brief clearing periods between clouds and snow.
A very deep long wave trough stretching from the North Pole south
over Alaska into the Gulf of Alaska will persist through Fri then
become progressive over the weekend as a ridge builds over the
Gulf of Alaska and Mainland Alaska. This trough has h500 heights
of less than 5000 meters of most of Northern Alaska and has
brought a very cold airmass to to most of Northern Alaska that
will persist through the end of the week, then begin to moderate
over the weekend.
A series of weak short wave troughs are making their way north
over the Eastern Interior and Eastern North Slope in the southerly
flow on the east side of the long wave trough. These short waves
will bring periods of clouds and flurries to the Eastern Interior
and Eastern North Slope through Tue, with clearing south of each
A weak short wave that lies from Denali to Old Crow will move to
Denali to Arctic Village by 3pm mon, to McGrath to Barter Island
by 3am Tue, to Anvik to Barter Island by 3pm Tue, and then weaken
slowly. There are mid to low level clouds and light snow or
flurries along this trough that will spread slowly north and west
with the trough. Clouds will scatter south of the trough.
A second weak short wave trough in the Gulf of Alaska will move to
along the Alaska range by 3am Tue, to Minchumina to Eagle by 3pm
Tue, then merge with the first short wave on Tue night. There will
be mid level clouds and flurries with this trough with clouds
becoming scattered south of it as well.
A strong short wave trough south of the Aleutians is stretching
east and will eject significant energy into the long wave trough
on Tue, which will move to the northern Gulf of Alaska Tue night,
and over the Eastern Interior Wed into Thu. This will bring snow
and slightly warmer air to the Interior Wed and Thu.
A 1032 mb high over the Chukchi Sea will weaken slowly through
Wed. A ridge of high pressure stretching from this high
east over the North Slope of Alaska will persist through Tue then
move north of the Arctic Coast on Wed. A low pressure trough
stretching from north of Prudhoe Bay to Atqasuk will move to
Barter Island northeast by 3pm Tue, and then dissipate.
Stratus along with patchy fog and flurries accompany the trough.
West winds 15-20 kt along the Eastern Arctic Coast are occuring
east of this trough, with the winds decreasing west of the
trough. This is causing Wind chills to 50 to 70 below in zones 203
and 204. North winds 15-30 mph blowing out of this high through
Brooks Range Passes are causing very cold winds chills along the
south slopes of the Brooks Range. This is also causing blowing
snow through passes.
A ridge of high pressure stretching from the Chukchi Sea south
over the Bering Sea will persist through Wed. A low pressure
system in the northern Gulf of Alaska will weaken slowly through
Tue. The gradient between these systems is causing north winds of
10-25 kt along the West Coast, with Capes and Points of the West
Coast having the strongest winds and coldest wind chills. This is
also causing NE winds along with blowing snow and cold winds
chills over Summits of the Elliott, Steese and Dalton Highways
south of the Yukon River. This is also causing north winds gusting
to 30 mph and cold wind chills and blowing snow through Alaska
A very strong low developing in the southern Gulf of Alaska on
Tue will move to the Northern Gulf of Alaska on Wed with an
occluded front moving to the Kenai Pen to Burwash Landing by 3pm
Wed. This will spread snow to the SE Interior Wed and Wed night
and over much of the Interior on Thu. This will also enhance north
winds between the Brooks Range and Alaska Range on Wed and keep
the cold wind chills going.
Models initialize well aloft at 00Z. Models show similar
solutions through 3pm Tue, then start to see differences on
timing and strength of strong low moving north over the Gulf of
Alaska Tue night and Wed.
850 mb temperatures range from -22C along the West Coast to -35C
over the Eastern Interior and Eastern North Slope. 850 MB temps
will remain cold into Tue, then begin to slowly increase Tue night
and Wed, with a more sharp increase on Thu.
With precip, models are similar through Tue with bands of light
precip moving north over Eastern Interior/Eastern North Slope. On
Wed the NAM and ECMF bring precip into the Eastern Interior a bit
quicker than the GFS. Given the entrenched low low cold air
over the SE Interior which will act as cold air damming against
the Alaska Range and limit downslope flow there, expect the
precip to develop more quickly as shown the the NAM and ECMF.
At the surface, models verify well at 06Z, and models show
similar solutions through 3pm Tue. After that time, the GFS
consolidates several surface low centers in the Gulf of Alaska
into one very deep center, while the NAM and ECMF maintain 2
separate centers. Given the spacial separation of the 2 low
centers on Tue, expect them to maintain as 2 separate centers into
Bottom line is we prefer a blend of the ECMF, GFS, NAM through 3pm
Tue for clouds, precip, winds, then use a blend of the NAM and
ECMF for winds, clouds, precipitation for Tue night and Wed.
Expect model surface temperatures to have fair amount of error in
this very cold airmass, but the North Slope and Western Interior
should remain in the 30s and 40s below through Tue night, with
slight moderation Wed, while the Eastern Interior and Eastern
North Slope range from the teens and 20s below when cloudy and
snowing, to 30s to 40s below during the brief clear periods
Coastal Hazard Potential Days 3 and 4...None.
Wind Chill Advisory for AKZ203-AKZ207-AKZ208-AKZ209-AKZ210-
Wind Chill Warning for AKZ204-AKZ206.
Winter Weather Advisory for AKZ218.
Brisk Wind Advisory for PKZ210-PKZ220.
JB JAN 20