Area Forecast Discussion
Issued by NWS Fairbanks, AK

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FXAK69 PAFG 311305

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
505 AM AKDT TUE MAY 31 2016


A transition from warm, dry conditions to more of a showery,
convective regime in the Interior will highlight the forecast
over the next few days. Overall, model consistency has been good
with fair agreement amongst the 31/00Z deterministic model suite
through Friday. There are subtle differences with positioning and
strength, more notably with the advertised arctic upper level low
and its reflection at the surface. The 31/00z ECWMF is more
aggressive by bringing the upper low south quicker and over the
North Slope rather than keeping the low center aloft over the
Beaufort Sea and its associated trough over Eastern Alaska like
the 31/00Z GFS through Friday. After Friday, the 31/00Z ECWMF and
GFS are vastly different in regards to what happens to the
aforementioned low. However, both models in the extended are
hinting at the return of weak riding aloft over Interior Alaska
late this weekend into early next week.

The 573 dam upper level ridge over the Chukotsk Peninsula will
move west today and over Siberia where it will remain through the
the rest of the week. An upper level low originating near 80N 150W and
its associated trough will dig southward through Wednesday evening
where the 524 dam low center will be around 330 miles north of
Demarcation Point with its negatively tilted trough stretching
south over Northern Alaska. At the surface, the surface reflection
of the upper low, a 1011 mb low will travel south from 80N and be
a 1009 mb low around 300 miles north of Demarcation Point by
Wednesday evening. A upper low and its surface reflection 73 miles
from Nikolski will remain quasi-stationary through Wednesday
morning before moving southeast towards the Northern Pacific.
Several upper level impulses will rotate around the aforementioned
low towards Southeast Alaska and then west along the Gulf of
Alaska Coast.

Modest cold air advection will ensue over most of Northern Alaska as
the Arctic upper level low moves south. The coldest H850
temperatures will be contained north of the Brooks Range, however
H850 temperatures will cool 5C to 8C by Friday over the Interior.
Over the North Slope, H850 temperatures ranging from +5C to +7C
this morning will quickly cool off throughout today and be 10C
colder by Wednesday morning. By Friday, H850 temperatures will
drop as low as -10C to -12C north of the Brooks Range.

ARCTIC COAST AND BROOKS RANGE: A wall of stratus and fog has moved
onshore over the Arctic Coast this past evening and early this
morning. Locations along the Arctic Coast are reporting LIFR
ceilings and visibility. At some spots, fog has been dense with
visibility under one quarter mile as well as some intermittent freezing
drizzle. Thus headlined dense fog for the Arctic Coast zones 201
through 204...except for zone 202 (Barrow) where visibility has
improved. Visible satellite imagery for late last evening shows
that the area of stratus is extensive, extending well north beyond
our offshore zones. Expecting LIFR to IFR ceilings to persist as
flow becomes northerly with the approach of the low from the high
Arctic. Visibilities in dense fog should improve by early
afternoon. Chances for light snow will increase along the eastern
Arctic Coast through the week as the aforementioned Arctic low
moves south.

WEST COAST AND WESTERN INTERIOR: Dry and warm conditions will
continue across much of Western Alaska through the next several
days as it remains under the eastern periphery of the upper level
ridge over Siberia. A thermal low that develops south of the
Eastern Brooks range this evening will move south Wednesday with
the western extent of the broad thermal low over the Middle Yukon
Valley and Upper Kuskokwim Valleys. This thermal low will be the
focus for showers and thunderstorms over the Middle Yukon and
Upper Kuskokwim valleys Wednesday. Continued chances for
thunderstorms through the rest of the week for these areas as the
upper level trough remains over the Southern Interior.

CENTRAL AND EASTERN INTERIOR: Today will mark the last day of
beautiful, warm and dry weather before the pattern transitions to
more of a convective/showery regime from Wednesday onward. A
thermal low will develop south of the Eastern Brooks Range today
and will shift south over the Southern Interior Wednesday as
cooler temperatures and the upper level trough pushes south from
the Arctic. This thermal low will be the focus for shower and
thunderstorm development during the latter half of the week and
into the weekend. Isolated thunderstorms will be possible
Wednesday south of the Eastern Brooks Range Wednesday and over the
Southeast and Alaska Range Thursday and Friday. Continued chances
for showers and thunderstorms across the area into the weekend.
Gap flow winds through the Alaska Range may be a possibility
during the latter half of the week with the thermal low positioned
over the Southern Interior.


.FIRE WEATHER...Dry and warm conditions will continue today.
Cooler air from the Arctic will move south over Northern Alaska Wednesday
and persist through the rest of the week. Low level moisture will
increase over the Interior and will keep afternoon relative
humidity values above 30 percent Wednesday and into the weekend.
A thermal low over the southern interior will be the focus for
isolated thunderstorms over the Interior Wednesday and over the
Southeast Interior and Alaska Range Thursday and Friday.


.HYDROLOGY...No issues are anticipated.


Small Craft Advisory for PKZ210-PKZ220-PKZ225.


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