High Surf in Alaska, September 30, 2017

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
229 PM AKDT Fri Sep 29 2017

.DISCUSSION...
Coastal flooding along the northwest coast, gusty winds and snow
in the Brooks Range are the are the main forecast concerns through
the weekend.

Ongoing coastal flood event in and around Barrow will continue
through this evening before winds and surf diminish later this
evening. Strong on shore winds of 25 to 35 mph with gusts to 45
mph combined with storm surge 1 to 2 feet above normal tide levels
along with 5 foot waves breaking on shore caused multiple
breaches in the sea wall and produced coastal flooding in and
around Barrow. As winds decrease tonight and storm surge levels
diminish coastal flooding is expected to end. High surf conditions
will continue tonight and into Saturday morning as strong along
shore winds and 4 to 6 foot off shore waves persist along the
eastern north slope coast.

Aloft at 500 hpa, a 508 dm low centered 250 nm northeast of
Barrow with a strong shortwave extending southwest to near Prudhoe
Bay and the central Brooks Range and southward into the western
interior will move north east to be located 400 nm north of
Demarcation point Saturday morning. The strong shortwave will move
east out of the western interior tonight sweeping through the
central and eastern interior by Saturday morning. Snow showers and
colder temperatures will accompany the front as it moves through
the interior. Warmer temperatures return aloft at 850 mb with
temperatures rising from 7 below on saturday morning to 3 below
Sunday morning over Fairbanks as an upper level ridge builds in
over the eastern Bering Sea and western and central interior.

Over the north slope the ongoing coastal flood warnings will
continue into this evening. As winds and surf diminish conditions
are expected to improve over the western north slope. Winds and
surf will diminish late tonight and Saturday morning over the
eastern north slope coast where high surf advisories are currently
in effect. Snow will continue to move east over the eastern north
slope as the surface low passes to the north. Favored west wind
upslope locations in the northeastern Brooks Range will receive
enhanced snowfall over the one to two inches that is expected to
fall over the plains of the eastern north slope Saturday and
Sunday.

Along shore southwest winds develop along the western north slope
coast late Saturday and Sunday and combined with storm surge
values in the 1 to 2 feet range will likely bring another round of
high surf for the western north slope coast. Wave run up is not
likely to compare to today's event in and around Barrow as the
winds will take waves along the shore versus up and over the beach
and up against the sea wall as happened today.

Over the interior light snow and snow showers are expected
tonight and Saturday morning as the strong shortwave moves east
through the interior. Generally less then 1 is expected to the
north of Fairbanks while trace amounts expected from Fairbanks
south.

A sharp ridge aloft develops over the eastern interior while deep
toughing develops over the central Bering Sea by Sunday night and
Monday. This will bring the potential for a strong chinook to
develop by Sunday night and Monday morning to the northern slopes
of the Alaska Range and southern interior. Continue to monitor for
the possibility of high winds developing along through the passes
and along the northern foothills of the Alaska Range Sunday night
and Monday morning.

On the west coast southwest winds develop ahead of a developing
low over the western Bering Sea low pressure system Sunday and
will continuing into Monday. Surge guidance is progged to reach 2
to 3 feet above normal tides along south and west facing coast
lines south of the Bering Strait with surge guidance progged to
reach 2 to 3 feet around the Nome area Sunday. A much stronger
storm moves into the central Bering Sea Wednesday and will produce
southwest winds along a long fetch from the central Aleutians and
will likely bring elevated surge levels to south and west facing
coast lines next week. Considerable differences exist on model
track and strength and will need be monitored closely.

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

&&

.HYDROLOGY...none.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Coastal Flood Warning for AKZ201-AKZ202.

High Surf Advisory for AKZ203-AKZ204.

Small Craft Advisory for PKZ210-PKZ220-PKZ230-PKZ235-PKZ240-
PKZ245.
&&

CCC SEP 17