Weather Service Report


416 
FXAK69 PAFG 202305
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
205 PM AKST Mon Feb 20 2017

.SYNOPSIS...
Aloft...
Northern Alaska will be in for a significant change in the weather
pattern in the second half of this week.

A long wave trough over Alaska will move east into Canada Tue 
through Wed as a sharp ridge builds over mainland Alaska from Tue 
through Thu. The ridge then flattens out Thu night through the 
weekend with the flow aloft becoming southwest. Several weak short
wave troughs moving northeast across Northern Alaska now through 
Wed in the long wave trough will bring flurries or light snow 
with each trough.

The current near to below normal temperatures will rise to well 
above normal by Thu over most of northern Alaska under the 
building ridge and remain above normal through the weekend.

Moist south flow moving into the West Coast of Alaska late Wed 
and Thu will bring significant snow the West Coast and Western 
Interior Wed night and Thu with 4 to 8 inches of accumulation. 
Flow will turn southwest Thu night through the weekend over all of
Northern Alaska bringing periods of snow from Thu night through 
the weekend with snow fall amounts of 4 to 8 inches across many 
areas in that 3 day period. Expect the heaviest amounts in SW 
facing slopes such as the Brooks Range. Could see snow mixing with
or changing to freezing rain across the SW Alaska Wed night and 
Thu and to the southern Interior Thu and Thu night. 

A low aloft near Kotzebue will move to Red Dog by 3pm Tue...and to
just north of Deadhorse by 3pm Wed then continuing northeast. 
There will be flurries and areas of mid-level clouds around this 
feature. A short wave trough extending from the low to Kodiak 
will move to Kotzebue to Minchumina by 3am Tue...to Red Dog to 
Northway by 3pm Tue...to Red Dog to Arctic Village by 3am 
Wed...and then north of the Arctic Coast Wed. Flurries and light 
snow along with and mid-level clouds northeast of the trough will 
clear out southwest of the trough. Surface low temperatures will 
fall into the 20s and 30s below in the clearing area.

A second short wave trough moving from the Bering to the YK delta
Tue night will move to the SE Interior Wed. There will be light
snow in the YK Delta and SW Interior Tue night spreading to the
Eastern Interior Wed. Expect 1-2 inches of snow with this.

Surface...
A vertically stacked 1019 mb low near Kotzebue will move to Red
Dog as a 1024 mb low by 3pm Tue and to 100 nm north of Deadhorse 
as a 1024 mb low by 3pm Wed. A front stretching from this low
south over Norton Sound then curving back north over the Bering
Strait to Point Hope to Point Lay to Eagle will move north and 
east of Alaska tonight. There will be NW winds g15 mph blowing 
with this front along the Alaska Highway from Tok to the Alcan 
Border. 

A strong low will move into the SW Bering Sea Tue night and to 
the NW Bering by Thu Pm. A warm front associated with this will 
move north over the Bering Sea to Nunivak Island west by 3pm 
Wed...to Anadyr to Provideniya to McGrath by 3am Thu...and to a 
997 mb low just north of the Bering Strait at 3pm Thu with the 
warm front stretching from the low to Point Hope to Denali by 3pm 
Thu. A trailing cold front will move to Anadyr south at 3am Thu 
and to the Bering Strait to the Yukon Delta as 3pm Thu. There will
be a chance of rain and freezing rain in the warm sector south of
Kotzebue. Expect 4-8 inches of snow and easterly gale force along
the west coast with the warm front. Winds will be much low lower 
in the Interior. Will issue Winter Storm watch for zones 214 and 
213 starting at 3pm Wed...for zones 212 and 211 after 9pm 
Wed...for zone 210 after 3am Thu...and for zones 207 208 and 209 
after 6am Thu. 

&&

.DISCUSSION...
Models show similar solutions through 3pm Thu. After that time 
they differ on details of timing and strength, but they all show a
similar long wave pattern with moist southwest flow developing 
over Northern Alaska from Fri through the weekend.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch for AKZ207-AKZ208-AKZ209-AKZ210-AKZ211-AKZ212-
AKZ213-AKZ214.

Brisk Wind Advisory for PKZ210.
&&

$$

JB FEB 17

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Western Regional Climate Center, wrcc@dri.edu