000
FXAK69 PAFG 060236
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
536 PM AKST Tue Dec 5 2023

.SYNOPSIS...
A weather front over the Southeast Interior will cause light snow
over the Interior SE of Tanana through Wed with 1-3 inches
accumulation, except for 3-5 inches in the Alaska Range where snow
may linger into Thu. Will see blowing snow and reduced visibility
in Isabell Pass tonight into Wed night.

Several weather front impacting the West Coast today and tonight
will bring periods of snow and blowing snow with briefly low
visibility tonight.

A strong weather system in the Western Bering Sea will move east
across the Bering Sea tonight and into the West Coast on Wed where
it will linger into Thu and then move into the Western Interior on
Fri. This will bring snow, blowing snow and strong winds to many
areas of the West Coast Wed and Wed night, with near blizzard
conditions from Nome to the Bering Strait and over the Norton
Sound and Yukon Delta Coasts on Wed, and from Kotzebue to Point
Hope on Wed and Wed night.

Expect Northwest winds of 40 gusting to 50 mph and snow squalls
from the Bering Strait to St Lawrence Is to the YK Delta Thu into
Fri and possibly into the weekend.

Aloft...
The long wave pattern consisting of a very deep trough over
Eastern Russia (with the Northern Hemisphere`s coldest air, with
500 mb heights less than 4900 meters) and a ridge over Western
Canada and Eastern Alaska, is becoming progressive with the trough
moving over the Bering Seas on Wed, over Western Alaska and the
Eastern Bering on Thu, and over AK from Fri into the weekend.
This is bringing a very stormy pattern to the West Coast the next
several days, and will bring much colder temperatures over Alaska
by the weekend with temps falling below normal south of the Brooks
Range.

Surface...
A 984 mb low 60 NM north northwest of Point Hope will move to 150
NM northwest of Point Hope as a 990 mb low by 3pm Wed, and then
dissipate in place Thu. An Arctic warm front extending east from
this low to Point Lay and then to Inuvik will move along the
Arctic Coast of Alaska from Utqiagvik east on Wed and then weaken
in place. An Arctic cold front from Point Lay to the YK Delta
will move to Utqiagvik to Denali by 3pm Wed, and then dissipate.
Flurries and fog will continue along the warm front with light
snow along the cold front diminishing as it moves inland tonight.

A strong low in the Gulf of Alaska will weaken through Thu.
An occluded front that has pushed aloft over the Southeast
Interior will remain in place through Wed then move east and
weaken on Wed night and Thu. Light snow is occuring over the
Interior south and east of Manley that will continue into Wed,
then diminish from the west on Wed night and Thu. Expect 1-3
inches accumulation in this area, except for 3-5 inches in the
Alaska Range where snow may linger into Thu.

A 984 mb low 200 NM west of Gambell will move to near Gambell as
a 980 mb low by 3pm Wed, to 60 NM south of Nome as a 987 mb low by
3pm Thu, and move over the Yukon Delta on Fri. This will bring snow,
blowing snow and southerly gales to much of the West Coast Wed
and Wed night, with near blizzard conditions from Nome to the
Bering Strait and over the Norton Sound and Yukon Delta Coasts on
Wed, and from Kotzebue to Point Hope on Wed and Wed night. On the
back side of the low expect northwest winds of 40 mph gusting to
50 mph and snow squalls from the Bering Strait to St Lawrence Is
to the YK Delta Thu into Fri and possibly into the weekend.


&&

.DISCUSSION...
Models initialize well aloft at 12Z, and models show similar
solutions aloft through 3pm Wed. After that time, the ECMWF and
Canadian models show similar solutions aloft through Fri while
the GFS and NAM are bit faster moving the low aloft over Norton
Sound to the South and SE faster than the ECMWF and Canadian
Models. Prefer the ECMWF and Canadian solutions aloft since they
are consistent with each other and have better consistency with
previous solutions.

With preciptiation models have similar general pattern but differ
on details especially with amounts. Will use a blend of models for
precip through Wed, then lean more on the ECMWF for Wed night and
Fri since it has the preferred solution aloft. Details include:
Light snow over the Interior south and east of Manley through Wed
with 1-3 inches accumulation, except for 3-5 inches in the Alaska
Range where snow may linger into Thu. Snow along the West Coast
diminishing this evening with another 1 inch or so. Light snow
spreading east into St Lawrence Is and the YK Delta after midnight
tonight then spreading to the remainder of the West Coast Wed
morning with an inch of two. A second and heavier band of snow
will move east to the Bering Strait to the YK Delta west by Wed
afternoon and spread over Norton Sound Wed evening. This will
bring 4-6 inches of snow Wed and Wed night from Nome to the Bering
Strait, and 2-4 inches over the YK Delta, St Lawrence Is and
Norton Sound Coast. On Thu snow will taper off to scattered snow
showers most areas, but a band of lake effect type snow showers or
squalls will develop Thu in NW flow from the Bering Strait to the
YK Delta including St Lawrence Is and continue into Fri and
possible into the weekend. This will bring 2-4 inches of snow to
those areas Thu and Thu night with several more inches on Fri, and
several more on the weekend. Snow spreading into the Western
Interior on Thu and possibly into the Eastern Interior on Fri with
an inch or two those locations.

At the surface at 15Z, models verify within several MB on most
features but all are 4-6 mb too weak on the low in the Gulf of AK.
Will use a blend of the ECMWF and Canadian models at the surface
since they are preferred models aloft. Will bump up north winds
developing through south side of AK Range Passes tonight and Wed
to account for the deeper than forecast low in the Gulf of AK.
Highlights of winds are:
West winds 25 kt over Norton Sound diminishing this evening. North
winds 15 to 25 mph through southerly exit regions of AK Range
Passes developing tonight and continuing into Wed night. SW winds
20-30 kt developing late tonight west of the Bering Strait and the
YK Delta moving over much of the West Coast by early Wed. South
winds increasing to 25-35 kt over Norton Sound and the YK Delta
about noon Wed through Wed evening, with SE winds increasing 25-35
kt from Kotzebue to Point Hope Wed noon through Wed evening. Will
see winds diminish much of West Coast except NW winds 25-35 kt
developing Bering Strait to St Lawrence Is to YK Delta on Thu and
continuing into Fri and possibly Sat.

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
AK...None.
PK...Gale Warning for PKZ801-802.
     Gale Warning for PKZ803-852.
     Brisk Wind Advisory for PKZ804.
     Brisk Wind Advisory for PKZ805.
     Heavy Freezing Spray Warning for PKZ806.
     Small Craft Advisory for PKZ806.
     Heavy Freezing Spray Warning for PKZ807-854-856-857.
     Small Craft Advisory for PKZ807.
     Brisk Wind Advisory for PKZ808-855.
     Brisk Wind Advisory for PKZ809.
     Brisk Wind Advisory for PKZ810-811.
     Heavy Freezing Spray Warning for PKZ812.
     Small Craft Advisory for PKZ816.
     Heavy Freezing Spray Warning for PKZ816-817-851-853.
     Small Craft Advisory for PKZ817.
     Gale Warning for PKZ850.
     Heavy Freezing Spray Warning for PKZ850.
     Gale Warning for PKZ851.
     Gale Warning for PKZ853.
     Small Craft Advisory for PKZ854-857.
     Small Craft Advisory for PKZ856.
&&

$$

JB