Scientific Forecaster Discussion
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Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
118 PM akdt Wed Aug 16 2017
the longwave trough situated along the West Coast of Alaska will
shift east by Thursday and remain over Mainland Alaska through
early next week. This will result in periods of rain or showers
and temperatures near or slightly cooler than normal persisting
across northern Alaska. No significant weather impacts are
anticpated at this time through the weekend.
Models intialized well and are in good agreement through Friday
with position and strength of features. Differences in model
solutions begin to develop by the weekend but the general
consensus is for the longwave trough to persist over Alaska into
A short wave trough over the interior will move north to the
central Brooks range tonight and to the Northwest Arctic coast
Thursday night. Upslope flow will enhance the preciptation as it
crosses the Brooks range with 1 to 1.5 inches of rain possible
between the Dalton Highway and Anaktuvuk Pass and up to 1 inch
possible on North Slope. The snow level will remain above 4500
feet so the bulk of the precipitation will fall as rain and runoff
into the rivers. Elsewhere across the forecast area, several weak
features will allow shower activity to continue over much of the
area. A thermal trough stretching Arctic Village to Chicken may
kick off some isolated thunderstorms in the eastern interior
The pressure gradient will remain generally weak over most of the
forecast area. Marine winds will stay below small craft the next
few days, although northwest winds may increase to 25 kt in the
Bering Strait on Friday. Persistent northwest winds 15-20 kt
across the Chukchi Sea will bring incresing waves to the Seward
Peninsula coast at Shishmaref thurday night and into the weekend,
but high surf or significant coastal erosion is not expected.
Coastal hazard potential days 3 and 4...none.
Fire weather...no issues with the cool and wet pattern.
Hydrology...rivers and streams in the central Brooks range, such
as in the Koyukuk river basin, are rising from recent rains. The
additional rainfall tonight and into thurday will bring water
levels to near bankfull on some smaller streams but flooding is
not anticipated at this time. A similar scenerio is expected on
some of the north draining rivers as well. Recent cooler
temperatures aloft in the eastern Alaska Range and wrangels has
significantly slowed down glacial runoff into the Tanana river.
The Tanana river near Tok has dropped considerably during the past
24 hours and overland flow causing flooding near the Tetlin
Village Road and high water along the Alaska Hwy should begin to
recede some during the next few days.