Area Forecast Discussion
Issued by NWS Fairbanks, AK

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000
FXAK69 PAFG 171228
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
428 AM AKDT Tue Oct 17 2017


.SYNOPSIS...
Aloft...
A long wave trough stretching from Banks Island to the Bering Sea
will progress over mainland Alaska Tue night then persist with
h500 heights falling through the end of the week. This means that
snowy conditions will continue through the week, with temperatures
falling through the week to below normal by the end of the week.

A 493DM H500 low just north of Banks Island will move to 300 nm
north of Prudhoe Bay as a 994DM low by 4pm Wed, and to 100 nm
northwest of Barrow as a 996 DM low by 4pm Thu, and over the
Seward Peninsula as a 494Dm low by 4pm Fri. Will see strong
instability and snow squalls as the cold air associated with this
low moves over the open water north of the Arctic Coast and West
Coast of Alaska.

Surface...
A surface low pressure trough extending from St Lawrence Island
to Fairbanks to Eagle will persist today, move to Ft Yukon to
Anvik by 4am Wed, move to Old Crow to McGrath by 4pm Wed and to
Eagle to Isabell Pass by 4am Thu. Will see isolated to scattered
snow showers along this feature. Showers will be mixed with rain
showers today along the West Coast.

A 990 mb low over Banks Island will move north. A cold front
stretching from the low to Deadhorse will persist through this
evening. Snow along this front will persist into tonight bringing
another 3 inches of snow. SW winds 25g35kt and blowing snow over
zone 204 persist through noon today.

A 998 mb low 300 NM north of Barrow will to 60 NM north of Barrow
as a 992 mb low by 4pm Tue, to Atqasuk as a 993 mb low by 4am Wed,
then quasi stationary through 4pm Wed as a 999 mb low, and moving
to near Kotzebue as a 996 mb low by 4pm Thu. A cold front
extending west from this low will move to Barrow to Cape Lisburne
by 4pm Tue, to Atqasuk to Anaktuvuk Pass to the Bering Strait by
4am Wed, to Barrow to Bettles to the Yukon Delta by 4pm Wed, to
Barrow to Arctic Village to McGrath by 4am Thu, and then east of
the Alcan Border by 4pm thu. Expect 4-6 inches of snow with the
low and cold front over zones 201 202 and 205 from this afternoon
through Wed night due to the cold air (with 850 mb temperatures of
-12C to -18C) over the open water. Also expect northwest to
 northeast winds gusting to 50 mph in the northwest quadrant of
 the low this evening into Wed morning over zones 201 202. Will
 see snow showers and north winds 20-30kt along and following the
 cold from Point Hope to the Bering Strait and St Lawrence Island
 tonight through Thu. Will see scattered snow showers spread
 inland with the cold front Wed and Thu and could see 1-2 inches
 of snow northwest facing slopes the front moves over such as the
 western Alaska Range and north side of the White Mtns.

&&

.DISCUSSION...
Models initialize surface low north of Barrow a bit further east
at 06Z than surface analysis indicates. The GFS tracks the low a
bit slower and further west than NAM and ECMF through Tue night.
Considering that the low will deepen this morning as it moves over
open water and that the GFS location was better at 06Z we favor
the slower and more westerly GFS location of the low through
tonight. After tonight model solutions similar through 4pm Wed,
and after that the ECMF is faster in tracking the deep low aloft
southward over the West Coast than the NAM and GFS. At this point
favor the slower NAM/GFS solution as the ECMF moves this feature
very quickly after 4pm Wed, and appears to be too quick for this
deep of a feature. This feature will need to be closely watched
for Wed night into Fri as it could cause High Surf to vulnerable
locations at Shishmaref and along Kotzebue Sound.

Coastal Hazard Potential Days 3 and 4...
High Surf zones 201 and 202 from 10pm tonight until 4pm Wed due
to northwest to northeast winds 30 mph gusting to 50 mph and
strong cold air advection. Due to short fetch length do not expect
flooding.

Elevated surf north facing shores zones 207 and 213 Thu and Fri,
though still much uncertainty due to uncertainties in surface low
locations Thu and Fri. This means chance Shishmaref could see high
surf Thu if winds are NW, but if winds are more northerly then
average surf.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
High Surf Advisory for AKZ201-AKZ202.

Winter Weather Advisory for AKZ201-AKZ202-AKZ204-AKZ205.

Small Craft Advisory for PKZ225-PKZ230-PKZ240-PKZ245-PKZ245.

Heavy Freezing Spray Warning for PKZ235-PKZ240-PKZ245.

Gale Warning for PKZ235.
&&

$$

JB OCT 17



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