FZAK30 PAFC 281537
ICOAFC

Sea Ice Outlook for Western and Arctic Alaskan Coastal Waters
National Weather Service Anchorage Alaska
735 AM AKDT Thursday 28 June 2018

...JUNE 2018 MONTHLY SEA ICE OUTLOOK...

Looking at the big picture, sea ice break up has slowed
significantly during June as expected due to thicker first year and
multi-year ice north of 70N. Alaska waters south of 70N are now sea
ice free. Sea ice in the Beaufort Sea has begun to melt out from the
coast, especially at river deltas.

As we look forward through September, we expect sea ice breakup to
continue to be slower than the past couple years as there is still a
higher concentration of multi-year ice through the Chukchi and
Beaufort Seas. We expect melting within the ice pack to the north of
that band of multiyear ice during July, August, and early September
as the ice there is thinner overall. The pattern of melting in this
area may be similar to 2016 when a band of ice remained off the
coast of Barrow through much of September before completely melting.

In the Beaufort Sea, we expect the sea ice to break up from the
Alaska coast northward as is common, however we expect to see the
main ice pack melt at a much slower rate than last year due to the
much more widespread multiyear ice that remains throughout much of
the Beaufort Sea this year.

Detailed information can be found in each pertinent section below.

...BREAK-UP OUTLOOK FOR THE CHUKCHI SEA...

For Point Hope to Icy Cape west to 170W, this area is expected to
be sea ice free for the season by the first week of July.

For Point Hope to Wainwright, sea ice throughout coastal waters to
20 nm offshore from Point Hope to Wainwright is expected to be sea
ice free by the 1st week of July.

Sea ice is expected to no longer be shorefast from Wainwright to
Barrow by the first week of July. Sea ice concentrations throughout
coastal waters to 20 NM offshore from Wainwright to Barrow are
expected to reach 3 tenths concentration then be sea ice free by the
middle of July.

For Icy Cape to Barrow west to 170W, sea ice concentrations are
expected to reach 3 tenths by the end of July and be sea ice free
for the season during the first half of August.

For the area north and west of Point Barrow to 75N and 170W, this
area may be sea ice free by mid-September. This will be highly
dependent on how fast the multi-year ice in the area melts. It is
possible that this area will not completely melt before new sea ice
begins to form in the fall.

...BREAK-UP OUTLOOK FOR THE BEAUFORT SEA...

From Point Barrow to Cape Halkett...sea ice is expected to no longer
be shorefast by the second week of July. Sea ice concentration to 20
NM offshore may reach 3 tenths by the first half of September and be
sea ice free for the season by mid-September.

For Point Barrow to Cape Halkett to 75N, this area is expected to
reach 3 tenths concentration during the first half of September and
be sea ice free for the season by mid-September. It is also possible
that sea ice will not melt back to 75N before freeze-up begins in
fall.

From Cape Halkett to Flaxman Island...sea ice is expected to no
longer be shorefast by the first week of July. Sea ice concentration
to 20 nm offshore is expected to reach 3 tenths by the end of August
and be sea ice free for the season by mid-September.

For Flaxman Island to Demarcation Point...sea ice is expected to no
longer be shorefast by the first week of July. Beyond the shorefast
ice, sea ice is thinner than the surrounding area. Sea ice has
already begun to melt in the Mackenzie River Delta area and that
area is expected to continue to expand westward through break-up.
Sea ice concentration to 20 nm offshore is expected to reach 3
tenths by the end of July and may be sea ice free for the season by
the middle of August.

From Harrison Bay to Demarcation Point to 75N, it is possible this
area will reach 3 tenths concentration by the end of August, however
it will more likely be sometime in September if it happens at all
before new sea ice begins to form again.