Winter Weather Advisory 72, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
419 AM AKDT Wed Apr 7 2021

Synopsis...Forecast anticipates a continued cooling trend with a
low- pressure system moving southwest through Scammon and Hooper
Bay starting early Wednesday morning. It continues its track along
the southern coast and adds some snowfall for the southern
portion of the Western Interior and the Central/Eastern Interior
Thursday into Friday morning. Also, weak troughing across the
Brooks Range will cause flurries east of Atqasuk, but no
significant snow accumulation is expected.

.DISCUSSION...

Models...Models continue to be in good agreement in the short-term
with the system near the Lower Yukon Delta for Wednesday and
Thursday with snowfall moving along the southern coast before the
return moisture flow enters into the Central and Southeastern
Interior and adds light snowfall from Fort Yukon southward. Less
than inch of snowfall is expected for most areas. Most models
continue to underplay wind speeds near Anaktuvuk Pass, as the
pressure gradient tightens along the Brooks Range, so forecasted
winds will lean more towards the NAM for wind speeds since they
are capturing the strongest winds at our windier locations

Aloft...At 500 hpa...A 491 dam system is located north of
Utqiagvik and will be moving southeastward, moving inland on
Wednesday afternoon. It will continue its track inland moving
aloft towards Fairbanks before shifting eastward as ridging in the
Western Interior and the Brooks Range slide behind the system.
Additionally, there is a 520 dam low-pressure system east of St.
Matthew Island that will move across the southern coast into the
Gulf of Alaska. It deepens to 510 dam before it is moved eastward
by the aforementioned ridge out of the West Coast. 850 hpa
temperatures begin the descent downward as the cold air associated
with the northern low sweeps inland. Models predict -30C to -37C
850 mb temperatures north of the Brooks Range and as the system
moves southward, -30 C temperatures move into the Western Interior
Thursday afternoon and near -25 C temperatures seen across the
Central and Eastern Interior. This cold airmass aloft will produce
record or near record cold temperatures over much of the Interior
Friday and into the weekend.

Surface...A weak high pressure has moved into the Interior which
has supported the general clearing we have seen in our forecast
area. As the low over southwest Alaska moves to the Gulf of
Alaska, the combination of the two systems will produced elevated
winds through the Western Interior and the passes in the Brooks
Range. As the low track eastward, it will produce snowfall for
much of the Interior through early Friday morning. Light
accumulation is expected but areas such as Scammon Bay and the
Eastern Alaskan Range could see reduction in visibility from
blowing snow with elevated wind speeds and falling snow occurring.
North winds through the Alaskan Range passes Thursday and Friday
onset with snowfall will reduce visibility due to blowing snow in
the area. By Friday afternoon, the low- pressure system will have
mainly exited our forecast area and a high pressure system will
build behind it.

Arctic Coast and Brooks Range...Relatively quiet weather expected
with temperatures dropping into the 30's below early Thursday
morning. Wind Chill advisories have been issued for the Chukchi
Sea Coast with wind chills expected to get as low as -55 along
the Brooks Range. Flurries may be seen across the Brooks Range
into Kaktovik but no significant accumulation expected on
Wednesday. From east of Ambler through Arctic Village, winds could
range from 10 to 25 kts with gusts up to 35 kts Thursday through
Friday morning.

West Coast and Western Interior...Low moving inland near Scammon
Bay will produce snowfall and wind gusts as high as 55 mph along
the coast and 35 mph inland which could cause brief visibility
problems for the Lower Yukon Delta. A Winter Weather Advisory has
been issued for the Lower Yukon Delta from Noon Wednesday to 6 AM
Thursday for blowing and drifting snow. Following the system’s
passage, the Western Interior will see temperatures plummet with
-30’s in the Western Interior and negative teens and twenties as
 you move closer to the coast. Wind Chill advisories have been
 issued for much of the Western Interior as wind chill values
 could approach 50 below early Thursday morning, dependent on how
 much the skies clear out and where.

Central and Eastern Interior...Temperatures expected to continue
cooling as minimum temperatures drop into negative teens and
twenties. Light snowfall under an inch is associated with the
system Thursday. Clearing of cloud cover is expected to move into
the Central Interior Friday which sets up the stage for near
record cold temperatures overnight into the negative -30's.

Coastal Hazard Potential Days 3 and 4...None.

Extended Forecast for Days 4 to 7...The West Coast and Western
Interior will receive snowfall and possible elevated winds in the
Norton Sound as a low-pressure system moves out of the Western
Bering Sea. The remaining regions can expect cool temperatures and
partly cloudy to mostly cloudy south of the Brooks Range.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory for AKZ201-AKZ202-AKZ207-AKZ208-AKZ209-
AKZ210-AKZ211-AKZ216-AKZ217.

Winter Weather Advisory for AKZ212-AKZ213-AKZ214-AKZ215.

Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ200-PKZ215-PKZ220.
&&

DA APR 21