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fxak69 pafg 212148 

Northern Alaska forecast discussion
National Weather Service Fairbanks Alaska
148 PM akdt sun Oct 21 2018

active weather pattern shaping up for northern Alaska with a
series of low pressure systems with attending fronts moving north
out of the Gulf of Alaska and into northern Alaska through the

the long wave pattern consisting of a trough over the Bering Sea
and western Gulf of Alaska and a ridge over northwest Canada and eastern
Alaska will persist through late this week. A series of strong
short wave troughs and associated surface low pressure systems will
move north out of the Gulf of Alaska and will bring a series of
fronts into the interior through this week resulting in periods
of rain, freezing rain and snow in the interior and strong winds
through the Alaska Range. The strong southerly flow will also keep
temperatures well above normal across all northern Alaska through
late this week.

a 976 mb low currently located over Bristol Bay will continue to
weaken and drift to the northwest and will be located over Cape
Newenham Monday morning and just south of Nunivak Island as a 986
mb low Monday afternoon. A front rotating around the low is
currently located along an Old Crow to Fort Yukon to Hooper Bay
line and will continue to weaken as it moves north and stalls in
the Brooks range and along the West Coast. The front is moisture
limited and is currently producing only light snow and rain over
the northern interior and West Coast. Gusty winds have developed
behind the front in the Alaska Range passes as a leeward side
trough develops along the northern foothills of the Alaska Range.
Winds are expected to remain below advisory criteria today in the
western and central Alaska Range but are expected to reach
advisory criteria and continue through midnight tonight in the
eastern Alaska Range. The gusty winds will diminish after midnight
tonight. Gusty east winds are also expected over interior Highway
summits and near Indian Mountain this evening but are expected to
remain below advisory criteria. Gusty east winds continue over
the eastern portions of the North Slope with the remnants of the
low pressure system currently located near Demarcation Point that
brought the mixed bag of precipitation over the interior yesterday
continues to weaken and move northeast into the Beaufort Sea.
Winds along the eastern North Slope are expected to diminish this
evening as the low moves out to sea.

The next low in a series of lows pushes northwest out of the
eastern Gulf of Alaska and will be located 200 nm south of Yakutat
as a 970 to 975 mb low Tuesday morning and deepens to around 960
mb as it moves west to near the Kenai Peninsula Tuesday night. A
front rotating north and west out of the Yukon around the low will
bring another round of precipitation into the southeast interior
Tuesday afternoon and into the central interior Tuesday night and
Wednesday. Precipitation type in the eastern and central interior
will again be highly dependent on time of day that the
precipitation falls, and the elevation that the precipitation
falls at. The storm will again bring a warm airmass from the mid
latitudes into the interior and will likely produce a mixed bag of
precipitation including rain, freezing rain, and snow that will
potentially impact travel Tuesday afternoon into Wednesday.

Strong southerly winds aloft on Tuesday night and Wednesday
morning will likely produce a Strong Mountain wave and produce
strong winds through the Alaska Range passes and along the
northern foothills of the Alaska Range. There remains considerable
differences on the exact track and timing of this next system
which will impact how strong the winds will be as well as the
type and amount of precipitation. Strong upslope flow develops
along the southern slopes of the Brooks range as the front
continues to move north out of the interior and into the Brooks
range with a period of heavy snow likely developing over the
southern slopes of the eastern and central Brooks range Wednesday
morning and a rain snow mix pushing northwest into the western
interior Wednesday. The precipitation continues to move north over
the North Slope Wednesday night and Thursday. Continue to

A third low pressure system moves into the northern Gulf of Alaska
Thursday night and into Friday morning and will bring another
period of strong winds through the Alaska Range passes and
another chance for mixed precipitation over the interior.

The 12z model suite initialized well and verified well against the
12z and 18z surface analysis, however the models continue to
struggle on the timing, strength and track of forecasted low
pressure systems with considerable spread between model families
and from run to run in the mid range and especially in the
extended range. These differences will manifest in significantly
different impacts especially on precipitation type in the interior
next week.

Coastal hazard potential days 3 and 4...none.


Afg watches/warnings/advisories...
Wind Advisory for akz226.

Small Craft Advisory for pkz200-pkz210-pkz220-pkz240-pkz245.

Heavy freezing spray warning for pkz240-pkz245.

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