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Northern Alaska forecast discussion 
National Weather Service Fairbanks Alaska
530 am akdt Tuesday Sep 27 2016

Discussion...

Models...good run to run continuity. They all initialized well
against the 06z surface analysis as well. They have done a fair
job in handling the major features of the ongoing event. GFS
based surge guidance continues to show elevated water levels for
the Norton Sound region Wednesday as a long fetch of westerlies
across the Bering Sea pushes water into the sound for about 15
hours. See West Coast section below for more details. For the
short term will use a blend of the current solutions and the
current database to maintain most of the continuity, but will lean
toward the NAM for the afternoon over the interior as it is less
aggressive with the preciptiation which should be ending behind
the front that will move through this morning. They continue to
show a high amplitude ridge building over the state for the
weekend and that will usher in above normal temperatures for most
areas.

Aloft...at 500 hpa...long wave trough with a 520 dam low 300 nm
north of Demarcation Point with the trough extending south over
the middle Tanana Valley to Seward this morning and continuing to
move east. It will move out of the state by late this evening. A
ridge that was over the central Bering Sea and eastern Siberia
Monday has moved east with the axis lying from Nikolai to Golovin
to Point Hope then northwest this morning. The ridge will continue
east and by Wednesday morning the axis will lie from Sand Point to
Whittier to Fort Yukon to kuparuk and northwest. Behind the ridge
a rapidly moving shortwave will swing around a 510 dam low over
Siberia to be over the central Bering Sea this afternoon and lying
over the West Coast from Cape Newenham to Buckland then northwest
to a 515 dam low that develops 300 nm west of wrangel island
Wednesday morning. The trough will continue east to be over the
eastern interior by late Wednesday evening and exits the state on
Thursday morning. A high amplitude ridge will start building over
Bristol Bay and the eastern Bering Sea Wednesday night and rotates
east over the West Coast on Thursday morning and continues to
build north through Friday as it moves over the central part of
the state. At 850 hpa...zero isotherm still well south of the
forecast area but will start pushing north and inland over the
West Coast today as the ridge builds north, then slops back south
of the area Wednesday. Significant warm up this coming weekend as
the zero isotherm pushes well north into the Arctic and current
forecasts push the temperatures over the interior in some areas to
almost 12 celsius.

Surface...a 1009 mb low over the eastern Arctic will move east as
the front that extends south to the middle Tanana Valley
continues to move east into the Yukon territory late tonight. Weak
ridging builds in over the interior and central Arctic coast
behind the front. A 976 mb low will move to 300 nm west of wrangel
island today as a weather front moves to the West Coast by mid
day with a strong pressure gradient extending from the eastern
Arctic to the Bering Strait and the eastern Bering Sea. A cold
front will move to the West Coast on Wednesday and move to the
western interior by Wednesday afternoon moving rapidly east across
the state late Wednesday into the Yukon territory. A surface ridge
will rotate around a 1038 mb low in the North Pacific to be over
the West Coast late Wednesday and continues east over the interior
Thursday as it build north over the Arctic as well.

Arctic coast and Brooks range...a mixed bag over the next few days
with the weather front bringing some heavier mixed precipitation
Wednesday. Expect some flurries over coastal areas today as the
stratus ceilings move over most of the area. Some lingering snow
this morning in the far eastern Brooks range as the front move
east, but no significant accumulation. Winds across the area will
swing from west to southeast through the day, then back to
southwest Wednesday. Winds speeds generally 5 to 20 mph with the
exception of the area south of Point Lay along the coast which
could see winds gusting to around 40 mph today. Big ridge of high
pressure building over the state late in the week will bring above
normal temperatures to most of the Arctic this coming weekend.

West Coast and western interior...going to be a busy couple of
days along the coastal areas with the first front already starting
to impact the Chukchi Sea, Bering Strait, and St Lawrence Island
this morning. Winds starting to pick up and will peak at gales
this afternoon in the coastal the rapidly moving cold front
associated with the system will move across the area Wednesday
with a rather long fetch of westerly winds that will last 12 to 15
hours, and be pointed directly into Norton Sound. Surge models
indicating 2 to 5 feet of surge for most locations in Norton
Sound, and around Kotzebue Sound and the Chukchi Sea coastal
areas. Will maintain the current coastal Flood Warning for zone
212 and the high surf advisories for the adjacent coastal areas.
Highest impact areas appear to be the Stebbins and Unalakleet
areas, and Golovin where some minor coastal flooding can be
expected. Kotzebue will also see some high surf and some high
water on the back side of town along The Lagoon. Winds will turn
from the south late Wednesday night and the southwest by mid day
Thursday. Winds along the coast will generally be 10 to 25 mph
Wednesday and diminish a bit on Thursday. Winds will pick back up
Thursday night from the southwest as a low pressure system moves
from the North Pacific into the central Bering Sea and the
gradient tightens across the area. Inland areas will see winds in
the 5 to 15 mph range through Friday.

Central and eastern interior...some scattered snow and rain
showers moving across the area this morning. They have already
ended in the Tanana area and are approaching the middle Tanana
Valley. Expect the showers to be east of Fairbanks by late
morning as the front continues its March east. Some patchy fog
this morning around the interior will lift out late this morning.
Winds will remain generally light. Temperatures steady through
Friday, but models are indicating a significant warm up for the
weekend. Another weather front that is moving to the West Coast
later tonight will move rapidly across the interior Wednesday
spreading a quick shot of snow that will quickly change to rain
to most areas for around 12 hours with 0.25 to 0.50 inch of rain
south of the Yukon. Winds generally light but may kick up to 10
mph gusting to 20 mph as the cold front moves through. Not much
change in temperatures next couple days, then looking at a Big
Warm up for the weekend with high temperatures reaching into the
upper 50s to mid 60s in some areas Saturday and Sunday.

&&

Coastal hazard potential days 3 and 4....none. See West Coast
section for current hazards.

&&

Hydrology...no immediate concerns.

&&

Afg watches/warnings/advisories...

Coastal Flood Warning for akz212.

High surf advisory for akz207-akz209-akz211-akz214.

Small Craft Advisory for pkz200-pkz215.

Gale Warning for pkz210-pkz220-pkz225-pkz230.

&&

$$

Sdb Sep 16

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