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fxak69 pafg 190012 
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Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
312 PM akst Mon Feb 18 2019

Discussion...

A brief period of quiet conditions expected for the West Coast
through Tuesday before the next storm Wednesday brings strong
winds, heavy snowfall, and possible blizzard conditions. Near
blizzard conditions expected west of utqiagvik tonight with gusty
winds and blowing snow, stronger winds are expected to develop
west of utqiagvik, with blizzard conditions expected for zones 203
and 204.

Aloft, at 500 mb, a broad longwave trough remains over the western
Bering Sea and dateline. A low centered over the western Brooks
range this afternoon will move northeast to centered over the
eastern Arctic coast by early Tuesday morning, weakening and
moving eastward through the day to be over the Yukon territory
Tuesday evening. Ridging is building north from a high in the
northwest Pacific, stretching across the Bering Sea and north to
the chukotsk peninsula this afternoon. The ridge axis will slide
eastward tonight to be stretched along the West Coast Tuesday
morning, across the western interior Tuesday afternoon, across the
central interior Wednesday morning, across the eastern interior
by Wednesday afternoon, with axis along the alcan border by
Thursday morning. Tuesday night a low develops in the western
Bering Sea, moving northeast to be north of the pribilofs
Wednesday morning, approaching St Lawrence Island by Wednesday
afternoon and moving into the southern Chukchi Sea by Thursday
afternoon.

Surface...an elongated area of low pressure with a 996 mb center
50 nm north of Nuiqsut stretches along the eastern Arctic coast
this afternoon. The low will move east northeast tonight and
weaken to 999 mb 100 nm north of Prudhoe Bay, with a second low
with a 1002 mb center developing near Richards Island by Tuesday
morning. The low north of Prudhoe Bay will move east to be 100 nm
north of Kaktovik Tuesday afternoon, continuing to weaken and move
eastward Tuesday night, becoming a weak trough near cape
dalhouise. The low near Richards Island will weaken and move
eastward inland Tuesday as a 1010 mb low.

High pressure is building in over the Bering Sea this afternoon
and will move eastward across the West Coast and western interior
tonight night and Tuesday, sliding eastward across the interior
eastward across northern Alaska Tuesday night and Wednesday.

The next low moves into the Bering Sea Tuesday morning to be 150
nm southwest of St George Island Tuesday afternoon as a 988 mb
low. The low continues to deepen as it moves north Tuesday night
to be a 976 mb low 50 nm southwest of St Matthew island Wednesday
morning, approaching St Lawrence Island Wednesday afternoon. The
low will weaken to 992 mb Thursday as it approaches the Bering
Strait.

Models...12z model suite initialized fair against the 12z radiosonde observations
and 12z surface obs. Models undercut the strength of the 500 mb
ridge, with ridge stronger than models advertising. Ridge is
stronger than what radiosonde observations show at 12z at 500 mb. Models are in fair
agreement through about 24 hours, before beginning to diverge
greatly with the timing and placement of lows, both along the
Arctic coast and in the Bering Sea. By Tuesday night, there a 100
nm spread in the placement of the low in the Bering Sea, with that
spread continuing as the low lifts north, resulting in a wide
range of solutions.

North Slope and Brooks range: a low along the eastern Arctic coast
this afternoon will move eastward overnight, as a weather front
pushes east across the North Slope. This will bring periods of
snow, increasing westerly winds, and blowing snow. Winter weather
advisories for blowing snow remain in effect for zones 201 and
202. Stronger winds are expected in zones 203 and zone 204, with
gusts to 45 mph in zone 203 and 60 mph in zone 204 producing
blizzard conditions. Upgraded the Winter Weather Advisory for zone
203 to a Blizzard Warning and upgraded the Winter Storm Watch for
zone 204 to a Blizzard Warning. As the front moves east, winds
will across increase across the Brooks range with wind gusts to 40
mph, bringing areas of blowing snow, especially to the eastern
Brooks range, where visibility will be reduced to one half mile or
less Tuesday. A Winter Weather Advisory remains for zone 206
beginning Tuesday morning. Snowfall accumulations of 1 to 2 inches
expected through Tuesday for the region.

West Coast and western interior: snow will taper off this
afternoon and evening. Quieter conditions expected Tuesday as high
pressure builds eastward across the area, with slightly cooler
temperatures expected. The next storm system approaches the West
Coast Wednesday, bringing another round of gusty winds, heavy
snow, and blowing snow. Winter storm watches have been issued for
zones 213, 214, and 211 for possible blizzard conditions. Heavy
snow is likely to accompany this system and periods of mixed
precipitation are possible in the y-k Delta.

Central and eastern interior: periods of snow expected through
Tuesday as another front moves east across the interior during the
day. Gusty westerly winds will accompany the front bringing areas
of blowing snow, especially to Highway summits in the interior,
along the Dalton and Steese highways. Snowfall amounts through
Tuesday will generally be in the 1 to 2 inch range. Pressure
gradient tightens across the interior on Wednesday, as the low in
the Bering moves north. Wind gusts to 40 mph likely in the
summits of the central interior. The Tanana Valley jet develops
Wednesday morning, peaking Wednesday afternoon and evening, with
gusts to 45 mph likely. Southerly gap winds return to the Alaska
Range passes Wednesday and Wednesday night and at this point in
time look to be below advisory level.

Coastal hazard potential days 3 and 4...a strong low moving north
in the Bering Sea Wednesday and Thursday will bring the
possibility of elevated water levels south of the Bering Strait.
Models solutions still have differences in timing, strength, and
track of the low. Will continue to monitor.

&&

Afg watches/warnings/advisories...
Winter Weather Advisory for akz201-akz202-akz206-akz218-akz219-
akz220.

Blizzard Warning for akz203-akz204.

Winter Storm Watch for akz211-akz213-akz214.

Gale Warning for pkz240-pkz245.

Brisk Wind Advisory for pkz215-pkz220-pkz225-pkz230-pkz235.

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