Small Craft Advisory 192, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
127 PM AKST Mon Nov 6 2017

.DISCUSSION...

Models...Short term has good agreement in the solutions, with
some disagreement in the midrange in resolving the shortwave that
will be moving to the West Coast Wednesday night/Thursday.
Extended periods are in better agreement as ridge builds over the
Bering Sea. All of the 06/12Z solutions initialized well against
the 06/18Z surface analysis with very little difference in the
position and strength of major features. Going with an equal blend
of solutions for most elements this forecast cycle, the
exception will be precipitation where we will use a blend of the
GFS and NAM initially, then blend in the ECMWF Wednesday night and
Thursday to expand the coverage over the interior.

Aloft...At 500 hpa...High amplitude ridge lies from a 581 dam
center South of Dutch harbor over Kuskokwim Bay to Wainwright this
afternoon, and will move to lie from Kodiak Island to Livengood
to then over 150W in the Arctic. By late Tuesday evening it will
lie from a 556 dam center over Yakutat over western Yukon
Territory and the Beaufort Sea as it continues east. A 498 dam low
over the Sea of Ohkotsk will move northeast to 200 nm west of
Wrangel Island by Tuesday morning at 495 dam. A shortwave
associated with the low will move from over the Dateline this
evening to the West Coast Tuesday morning, then northeast up over
the ridge. A second shortwave will move to the central Bering Sea
by Tuesday morning, and over St Lawrence Island and the Southwest
Coast Tuesday evening before moving northeast across the state. A
third shortwave will move to the central Bering Sea Wednesday
afternoon and over the mainland south of the Bering Strait
Wednesday night, and moving across the state south of the Brooks
Range on Thursday. At 850 hpa...-10 isotherm lies from McCarthy
to Gulkana to Kuparuk and will very slowly moves east to into the
Yukon Territory by Tuesday morning. As the ridge builds and moves
east over the west coast a surge of warm air will push north over
the West Coast and Chukchi Sea. Zero isotherm currently lies from
the Semidi Island to Wainwright and north into the Chukchi Sea.
By Tuesday morning temperatures over the Central Interior and
Arctic will be at or above zero. A cooling trend will push
temperatures below zero by Wednesday morning, and below -10 by
Thursday morning.

Surface...High pressure associated with a 1035 mb high over
Dawson YT extends west over the Interior, then southwest over the
Lower Yukon Delta this afternoon and will shift southeast as a
weather front associated with a 976 mb low over Siberia pushes to
the West Coast tonight, then works northeast across the state
Tuesday. The low over Siberia will move north to 200 nm west of
Wrangel Island by Tuesday morning. A strong pressure gradient
around the low will move over the eastern Bering Sea, Bering
Strait, and Western Arctic this evening and persist into Wednesday
before is relaxes. Leeside troughing north of the Brooks Range
will combine with high pressure over the Upper Yukon Flats to
produce a strong gradient across the Brooks Range with strong gap
winds developing near the passes and persisting into Tuesday
evening. Strong south flow over the Bering Sea will produce
elevated sea levels as the fetch swings from south to southwest
Tuesday. A second front will move to the eastern Bering Sea
Tuesday as a 988 mb moves across the Gulf of Anadyr and enhances
the strong winds in the Bering Strait, and Norton and Kotzebue
Sounds. As the low moves northeast across the Chukchi Sea and into
the Arctic it will enhance the strong winds over the Northwest and
Central Arctic Coast. The second front will also usher in some
heavy precipitation Tuesday evening to the western Brooks Range,
and snow will fall over much of the West Coast before falling
apart as it moves inland. A third front will move to the coast on
Wednesday evening spreading another round of mainly snow to the
West Coast and Western Interior.

Arctic Coast and Brooks Range...Approaching system will spread
significant weather to the Western Brooks Range this evening as
winds ramp up and the Central and Eastern Brooks Range as the
evening goes on. Winds gusting to around 40 mph will kick up some
blowing snow reducing visibility at times to less than one half
mile. The first of three systems will bring some snow to the
Western Brooks Range, but expect significant snowfall with the
second and thirds systems that are lining up. Strong south winds
over the Chukchi Sea will produce some High Surf along the
Northwest Coast to Point Barrow. Winds along the coast and in the
Plains will be generally south at 15 to 25 mph with some gusts to
around 40 mph on the Northwest Coast.

West Coast and Western Interior...Significant weather event will
be impacting the area for the next few days. Strong south winds
increasing this evening with gusts to 65 mph in the Bering Strait
and around Point Hope this evening, with winds diminishing
overnight. Snow with this first system tonight through Tuesday
afternoon, but generally less than 2 inches. The second system
will be moving into the area Tuesday evening and spread
significant snowfall to portions of the Seward Peninsula and
Noatak Valley where 5 to 8 inches of snow is expected by Wednesday
evening. The strong winds are pushing water into Norton Sound, and
as winds swing around to west and increase again to 25 to 35 mph
Coastal Flooding will impact Golovin, and to a lesser extend other
areas of Norton Sound and the Lower Yukon Delta so Warnings and
Advisories are being issued.

Central and Eastern Interior...Stratus will not go away, so
expecting it to hang around overnight before breaking up, but
would not be surprised if it breaks up earlier. There is nothing
currently indicating that will happen though. Expect a short
period of snow Wednesday night, otherwise no significant weather
expected until the weekend. Winds generally light and variable.
Temperatures warm a bit, but then cool through the weekend.

&&

Coastal Hazard Potential Days 3 and 4...A 981 mb low moving
through the Chukchi Sea Saturday and Sunday move into northwest
Alaska and produce strong winds and push water into Kotzebue
Sound. Currently there is moderate potential for Coastal Flooding
in the area.

&&

Extended forecast for days 4 to 8...A very strong low will move to
the northwest coast Saturday evening bringing a period of near
blizzard conditions to most areas north of the Alaska Range
Saturday night and Sunday. Snowfall will range from 4 to 12
inches, and winds increase to 25 to 35 mph gusting to 50 mph, and
blowing snow reducing visibility significantly.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

High Wind Warning for AKZ207-AKZ213.

High Surf Advisory for AKZ201-AKZ202-AKZ207.

Coastal Flood Advisory for AKZ212-AKZ213-AKZ214.

Winter Weather Advisory for AKZ205-AKZ206.

Coastal Flood Warning for AKZ211.

Winter Storm Warning for AKZ208-AKZ210-AKZ212-AKZ217.

Heavy Freezing Spray Warning for PKZ215-PKZ235-PKZ240-PKZ245.

Small Craft Advisory for PKZ200-PKZ215-PKZ230-PKZ235-PKZ240.

Gale Warning for PKZ210-PKZ220-PKZ225-PKZ230.

&&

SDB NOV 17