Small Craft Advisory 82, NWS Fairbanks, AK

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
242 PM AKDT Thu Aug 10 2017

.DISCUSSION...
A weather front sweeping down from the northwest Arctic will
bring active weather to western and northern Alaska through the
weekend. Colder air is still expected to move into the state but
not as extensive as previously thought. Models are in good
agreement with the large scale synoptic features aloft in the
short term but begin to stray apart with solutions early next
week. A closed upper level low over Bristol bay will progress east
to the Alaska Panhandle by Sunday as a strong upper level trough
digs southward from the Arctic into the west coast. This trough
will drift east across the Interior and bring generally unsettled
weather to much of the forecast area on Sunday.

At the surface, models have had a difficult time coming to a
common solution for the track of the low pressure center
currently near Wrangel Island. All models are now in line and
rapidly sweep this low east tonight to pass about 150 nm offshore
of Barrow as 992 mb low and then continue northeast through
Friday night. A trailing weather front associated with this low
will move into the northwest Arctic coast this evening and the
remainder of the west coast on Friday. A broad area of low
pressure extending from Kotzebue Sound south to Norton Sound and
the remnant front will perist into Saturday.

As this front moves onshore, it will spread significant rainfall
into western Alaska which will continue over the west and
northwest coast into Saturday. Strong cold air advection and north
winds behind the front will impact this region as well. The colder
air will spread east along the North Slope and Brooks Range on
Saturday and Sunday bringing some accumulating snowfall,
especially to high elevations. The airmass and eastward extent of
the cold air is not as strong as orignally expected, so heavy snow
in the eastern Brooks Range is less likely but a few inches of
snow are still anticipated from the Dalton Highway westward,
including Atigun Pass. In addition to cooler weather and some rain
and snow, north winds 25 to 35 mph with higher gusts are expected
in the Brooks Range.

North winds 25 to 35 knots over the Chukchi and northern Bering
Sea will develop Friday after the frontal passage and perist into
Sunday. This will bring elevated surf to north facing coastlines
from Point to Saint Lawrence Island. For the northern Seward
Peninusla, the trajectory is slightly northeast which is less
favorable for any minor coastal flooding and only elevated surf
and some minor beach erosion is anticipated for Shishmaref.

Coastal Hazard Potential Days 3 and 4...
Strong north to northeast winds will persist Sunday and Monday
from the Beaufort Sea coast to Saint Lawrence island. Elevated
surf will likely continue to be an issue on north facing
coastlines.

&&

.FIRE WEATHER...
No concerns at this time. Relative humidities in the eastern
Interior will rise into the 30's and 40's on Friday. Southerly
winds will develop through Alaska Range passes this weekend but
relative humidities will increase as showers move into the area.

&&

.HYDROLOGY...
In addition to the heavy rain associated with the incoming west
coast weather front, a disturbance moving northwest through the
western Interior will bring 1-2 inches of rain tonight and Friday
to the south slopes of the western Brooks Range in the upper Kobuk
and Noatak River basins. Rain will persist over this area. Sharp
rises are expected on small streams and rivers in tonight and
Friday with bankfull conditions possible. Elsewhere, 1-2 inches of
rain is also expected over the southern Seward Peninsula Friday
night and Saturday. Flooding continues on the road to Tetlin
Village near Tok from the Tanana River. The Tanana River level will
remain steady through the weekend so minor flooding will continue.

&&

AUG 17

Special Weather Statement
National Weather Service Fairbanks AK
308 PM AKDT Thu Aug 10 2017

AKZ205-206-111500-
Northwestern Brooks Range-Northeastern Brooks Range-
Including Singiluk, Umiat, Anaktuvuk Pass, Atigun Pass,
Galbraith Lake, Sagwon, and Franklin Bluffs
308 PM AKDT Thu Aug 10 2017

...Strong winds and snowfall Likely in the Brooks Range this
Weekend...

An unseasonably cold, wet and windy storm will impact northern
Alaska with the potential for snowfall of 2 to 6 inches at higher
elevations of the Brooks Range this weekend. The heaviest snow
will be west of the Dalton Highway. A strong cold front will push
east across the Brooks Range Saturday and Sunday. Snow levels will
drop to 1000 feet or lower by Saturday evening in the western
half of the Brooks Range and near 4000 feet from the Dalton
Highway eastward by Sunday night. Along the Dalton Highway, up to
3 inches of snow is possible at Atigun Pass. North winds from 25
to 35 mph with locally higher gusts are likely through passes and
over higher terrain.

Those with outdoor activities or travel plans in the Brooks Range
especially from Atigun Pass westward over the weekend should be
prepared for winter weather conditions. There still remains some
differences with the eastward extent of the cold air associated
with this weather system. The location of and amount of snow
expected with this storm will likely change as the storm
approaches, but at this time it looks unlikely for significant
snowfall east of the Dalton Highway. Continue to monitor the
situation for the latest forecasts and possible winter weather
statements on this early season storm.