Winter Storm Warning 25, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
348 PM AKST Thu Nov 29 2018

.DISCUSSION...

Synopsis...
A busy end to the week is expected for much of the west coast and
western Interior. A series of lows will track northward up the
coast, with widespread potential for heavy snow and ice, gusty
winds, near zero visibility, and coastal impacts.

Aloft 500 mb...
A 492 dam low east of Kamchatka lies near the center of a broad
longwave trough spanning much of eastern Siberia into the central
Bering Sea. The low will remain in place through the weekend as it
spawns a series of shortwaves along its southeastern periphery
over the Aleutians. These waves will sweep northward along the
west coast and into the Chukchi Sea by late Saturday, presenting
a wide range of winter weather hazards for much of the west coast
and western Interior. A 526 dam low in the Gulf of Alaska will
move southeast to the Washington coast by late Friday.
Southeasterly flow along the northers periphery of this system
will support snow showers across the eastern Interior through
early Friday. The low will be followed in quick succession by a
North Pacific ridge which will amplify Friday and Saturday ahead
of the longwave trough in the Bering Sea. A weak ridge axis
extends northwest from a 536 dam high over northwestern Canada.
This feature will dissipate as it is absorbed into the larger
North Pacific ridge Saturday.

Models...
Aloft, there is reasonable agreement with the longwave pattern
through this weekend, before several discrepancies become
apparent Monday with regard to the position and strength of the
North Pacific ridge. At the surface, models have generally
consolidated towards a common solution involving a singular deep
low moving up the coast Saturday. The ECMWF remains an outlier
with regards to strength and track of the low, particularly as it
transits the Chukchi Sea early Sunday, so a mainly GFS based
solutions remains the favored scenario. The second system remains
highly variable with solutions varied from a second bomb low to a
conglomeration of smaller spinups. Each solution presents wildly
different impacts to the coast, so for now we will continue to
lean towards the GFS in the mid range, as this is a good
compromise of solutions and allows continuity.

North Slope and Brooks Range...
A dissipating low over northeastern Siberia extends a weak trough
east across the Chukchi Sea and North Slope. Scattered snow
showers and low stratus will persist across the area. A small
surface low north of Prudhoe Bay will meander slowly, facilitating
greater chances for snow showers near and east of Prudhoe Bay.
Gusty winds associated with a tight gradient along the Chukchi
coast north of Cape Lisburne continue to support blowing snow and
visibility reduction to around a mile at times. Winds will
gradually diminish into Friday. A potent front associated with a
deep cyclone in the Bering Sea will impact the central and eastern
Brooks Range early Saturday, and reach the North Slope by Saturday
evening. Strong easterly winds and moderate snowfall is expected
along the front mainly west of Utqiagvik. Southerly flow behind
the front should preclude any significant snowfall across the
Arctic Plains, with accumulation generally less than 2 inches
through Sunday. Heavier snowfall will be observed south of the
Noatak Valley.

West Coast and Western Interior...
A 976 mb low approximately 300 nm west of St. Lawrence Island will
swing north into Siberia as an associated front moves onshore
across the Y-K Delta. The front stretches southeast from the low
to St. Lawrence Island, Nunivak Island, then southwest to Atka.
Moderate snow and gusty winds associated with the front have
prompted Winter Weather Advisories through Saturday for much of
the Yukon Delta, lower Yukon Valley, Norton coast, and St.
Lawrence Island through early Friday. Snowfall of 2 to 4 inches is
expected for most areas with the initial wave. A second low will
deepen rapidly over the southern Bering Sea late Friday into
Saturday as it swings a second powerful front northward across the
Y-K Delta and into the Norton Sound and Western Interior. This
will be the more impactful event, as deep saturation combined with
warm advection will create a multitude of hazards ranging from
mixed precipitation and ice for the coast south of the Bering
Strait and lower Yukon and Kuskokwim Valleys, to heavy snow along
the higher terrain and areas farther north to the southern Brooks
Range. Winter Storm Watches are in effect for the northern regions
into Sunday. Coastal impacts are likely with this system as it
tracks north through the Bering Strait late Saturday, maintaining
975 mb and packing southerly winds gusting up to 60 mph. See
Coastal Hazard section for details.

Central and Eastern Interior...
Isolated snow showers and broad overcast will persist through
early Friday for much of the region. A ridge will sweep east
Friday, permitting a brief clearing of skies before more
interesting weather begins early Saturday. As the Bering low move
north across the coast will swing a powerful shortwave north,
bringing snow to portions of the central Interior and forcing a
tightening of the pressure gradient across the Alaska Range. Mid
level support seems marginal as winds will be oriented
southwesterly. But at the surface, a sharp gradient will result
in high winds through passes and a strong Tanana Valley Jet
beginning early Saturday. Chinook conditions will keep much of the
Tanana Valley dry, though decent chances for snow exist farther
north, particularly along the central Brooks Range beginning early
Saturday.

Coastal Hazard Potential Days 3 and 4...
A deep low will move north through the eastern Bering Sea
beginning late Friday before entering the Chukchi Sea by Sunday.
This system has the potential to bring elevated water levels to
the west coast as well as Bering Sea islands. Southerly winds
will favor south and west facing shores for the highest water and
surf. Coastal interests should continue to monitor for updates and
statements.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
High Wind Watch for AKZ225-AKZ226.

Winter Storm Watch for AKZ207-AKZ208-AKZ209-AKZ210-AKZ217.

Winter Weather Advisory for AKZ211-AKZ212-AKZ213-AKZ214-AKZ215-
AKZ216-AKZ227.

Heavy Freezing Spray Warning for PKZ200-PKZ210-PKZ220-PKZ225.

Small Craft Advisory for PKZ200-PKZ220-PKZ225.

Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ215-PKZ230.
&&

COWMAN NOV 18

Special Weather Statement
National Weather Service Fairbanks AK
1129 PM AKST Thu Nov 29 2018

AKZ207>214-010200-
Chukchi Sea Coast-Lower Kobuk and Noatak Valleys-
Baldwin Peninsula and Selawik Valley-
Northern and Interior Seward Peninsula-
Southern Seward Peninsula Coast-
Eastern Norton Sound and Nulato Hills-
St Lawrence Island and Bering Strait Coast-Yukon Delta-
Including Point Hope, Shishmaref, Kivalina, Espenberg, Noatak,
Kiana, Red Dog Mine, Kotzebue, Selawik, Noorvik, Buckland,
Deering, Candle, Council, Haycock, Pilgrim Springs,
Serpentine Hot Springs, Taylor, Nome, White Mountain, Golovin,
Unalakleet, Stebbins, St Michael, Elim, Koyuk, Shaktoolik,
Gambell, Savoonga, Brevig Mission, Teller, Wales, Diomede,
Mountain Village, Emmonak, Alakanuk, Kotlik, Pilot Station,
St Marys, Scammon Bay, Marshall, Nunam Iqua, and Pitkas Point
1129 PM AKST Thu Nov 29 2018

...Strong Storm To Bring Elevated Water This Weekend...

A strong storm system will move north along the west coast of
Alaska Saturday into early Monday. Strong winds associated with
this system have the potential to bring elevated water along the
coast this weekend. At this point, there is still uncertainty in
the exact track of the storm system. The track of the storm will
affect how high the water will get in a given location. Coastal
residents are advised to monitor www.weather.gov/fairbanks for the
latest forecast information.