Area Forecast Discussion
Issued by NWS Fairbanks, AK

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000
FXAK69 PAFG 212236
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
236 PM AKDT Sat Apr 21 2018

.SYNOPSIS...
Aloft...
A low near Nunivak Island will move near the Pribilof Islands by
4am Sun, persist through Sun PM, then move to the central Bering
by 4pm Mon, and persist there into Tue.

A weak short wave south of the Alaska Range will move over the
southern Interior tonight and weaken. A second and stronger
short wave will move north over SW Alaska Mon. Weather with these
features will be addressed with surface frontal systems below.
South flow aloft will gradually increase Sun and Mon causing weak
chinook conditions and warming temperatures over the SE Interior.

A third and much stronger short wave moving north over the West
Coast and Western Interior Tue will bring stormy conditions to the
West Coast and Western Interior Tue, and strong Chinook
conditions to the Eastern Interior Tue.

The low aloft will weaken and progress east late next week causing
cooling conditions late next week.

Surface...
A 1028 mb high over the Chukchi Sea will build east over the
Beaufort Sea Sun and Mon, then persist into Tue.

A low pressure trough from Barrow northeast will move northeast
tonight then weaken. Patchy stratus and fog is associated with
the trough.

A 995 mb low near Nunivak Island will move tot he southeast Bering
Sea tonight, then strengthen to 983 mb by 4pm Sun, then move to
the Central Bering as a 970 mb low by 4pm Mon and persist into
Tue. An arctic front stretching from the low to Minchumina to
Chicken will move to Unalakleet to Galena to Chicken by 4am Sun,
to Gambell to Huslia to Eagle by 4pm Sun, to the Bering Strait to
Hughes to Eagle by 4am Mon, to the Bering Strait to Coldfoot to
Old Crow by 4pm Mon then moving along the Brooks range Mon night.

East winds 15-25kt are occuring just north of the front with gusts
to 35 kt along the West Coast. Winds will decrease slowly tonight
and Sun. Snow just north of the front in the southwest Interior
will mix with rain this evening then diminish. Little if any snow
expected in the Central and Eastern Interior with this front due
to increasing chinook conditions. Could see a few flurries along
the front Sun into Mon.

An occluded front moving into SW Alaska Sun, will move north over
Norton Sound and the SW Interior Mon, and then dissipate. This
will bring east winds back up to 20-30kt along the West Coast and
10-20 kt over the Interior. Rain with the front will change to
mixed rain and snow along and south of the front.

A frontal wave developing in Bristol Bay Mon night will move to
the Yukon Delta as a 977 mb low by 4pm Tue. This will bring more
rain and snow to to the West Coast and Western Interior Tue.
This will likely cause a strong chinook event to develop over the
Alaska Range and SE Interior Tue.

&&

.DISCUSSION...
Models initialize well above the surface and show similar
solutions through 4pm Mon, then see differences on strength and
timing of short wave troughs and surface centers after that.
Prefer the ECMF solution for Monday night Tue as the strong short
wave moving north over southwest Alaska should keep the main
energy further east per the ECMF solution, not move energy west
as the GFS does on Tue.

At the surface, all models initialize several mb too weak at 15z
on high over Chukchi Sea, and as a result have winds 3-5 mb too
weak over the West Coast and NW Interior. Expect the stronger
winds to persist today, but differences should become less
noticeable tonight as the surface low moves southwest and the
gradient relaxes. Significant differences in model surface fields
show up after 4pm Mon, and we are using the ECMF after that time
for reasons stated above.

Coastal Hazard Potential Days 3 and 4...
Elevated surf North Side of St Lawrence Island now through Mon,
but waves should be breaking offshore due to reduced sea height.

&&

.FIRE WEATHER...
None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Heavy Freezing Spray Warning for PKZ200-PKZ210.

Small Craft Advisory for PKZ200-PKZ210-PKZ220.

Brisk Wind Advisory for PKZ225.

&&

$$

JB APR 18



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