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FXAK69 PAFG 230108
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
408 PM AKST Tue Jan 22 2019

.DISCUSSION...
A series of weather fronts moving north along the West Coast will
bring periods of strong and gusty winds, snow, and blowing snow to
the West Coast into Wednesday. Strong southerly flow aloft will
allow for a moderate chinook to develop in the Alaska Range
tonight and Wednesday, bringing a warm up for areas south of the
Brooks Range.

Aloft, at 500 mb, a long wave trough over the Bering will persist
through the week, with various lows and shortwaves rotating
through the flow. Upper level ridging will continue to build
across the state through tonight. A progression of shortwaves
across the West Coast will push the ridge axis to the east through
Friday.

Surface...A lee side trough north of the Brooks Range will deepen
through Thursday with a pinch developing near Demarcation Point. A
closed low will develop near Demarcation Point by Wednesday
night, continuing to deepen and will slide eastward Thursday to be
near Mackenzie Bay.

A 963 mb low 150 NM northeast of Atka this afternoon will move
northwest to be a 965 mb low 375 NM northwest of Adak by Wednesday
morning and 150 NM northwest of Shemya Wednesday afternoon. The
associated weather front will lift north across the West Coast
into Wednesday.

A 973 mb low north of Cold Bay Wednesday morning will lift north
to be a 979 mb low near Toksook Bay Wednesday afternoon and a 988
mb low near the eastern side of St Lawrence Island by Thursday
morning, further weakening and becoming part of the inverted
trough along the West Coast. The associated weather front
stretching east from the low will move north across the West Coast
and Interior Wednesday and Thursday.

Models...12Z models initialized well against the 12Z RAOBS and
fair against the 12Z and 15Z surface obs. 12Z surface obs showed a
tighter pressure gradient associated with an inverted trough on
the West Coast, than what models captured from Kotzebue Sound
south to the Seward Peninsula and to a lesser extent the Y-K
Delta. Observations were 2 to 4 mb lower than model solutions.
This has resulted in strong winds than previously forecast. Models
are in fair agreement with the overall synoptic pattern through
Thursday. Mesoscale differences become apparent by Friday 12Z,
with the lows and shortwaves near the Aleutians and in the Bering
sea. By Thursday, model guidance indicate a number of surface lows
developing along the Aleutians, but the strength, path, and
timing of the lows is different for each model, lowering already
low confidence in model solutions.

North Slope and Brooks Range: Wind chill values remain a concern
tonight for the North Slope with temperatures in the 20 to 30
below zero range. Winds will stay up over the western North Slope
where wind chills of around 55 below zero will remain possible.
Upgraded the Wind Chill Advisory in zone 201 to a Winter Weather
Advisory to address the blowing snow at Point Lay. Southerly winds
will increase this evening and tonight and remain gusty through
Thursday morning in the eastern Brooks Range, especially in the
passes, with gusts to 35 mph possible. A front moving across the
Brooks Range Wednesday night and Thursday will bring a round of
snow and blowing snow.

West Coast and Western Interior: A frontal wave moving north
along the coast this evening and into Wednesday morning will bring
gusty easterly winds, snow, and areas of blowing snow. Another
front will move into the Y-K Delta early Wednesday and continue
northward through the day, keeping winds up and bringing another
round of snow and blowing snow. Snowfall totals through Wednesday
will range from 2 to 4 inches, with isolated higher amounts in the
favored upslope areas. Highest snowfall totals will fall in the
Nulato Hills. Temperatures will trend upward the next several
days.

Central and Eastern Interior: Gusty easterly winds continue over
the highway summits in the Central Interior tonight, diminishing
by morning. This will bring areas of blowing snow to summits along
the Dalton in zone 219. High pressure building north into the
Interior will induce a weak mountain wave across the Alaska Range,
allowing for a moderate chinook to develop tonight continuing into
Wednesday and diminishing Wednesday night. Tanana Valley Jet will
strengthen tonight into Wednesday with gusty east to southeasterly
winds expected near Delta Junction. Wind Advisories remain in
place for zones 223, 225, and 226. The southerly flow will bring
warmer temperatures over northern Alaska for the end of the week.

Coastal Hazard Potential Days 3 and 4...None.

&&

.AFG WATCHES/WARNINGS/ADVISORIES...
Wind Advisory for AKZ223-AKZ225-AKZ226.

Winter Weather Advisory for AKZ201-AKZ209-AKZ213-AKZ214-AKZ215-
AKZ219.

Gale Warning for PKZ210.

Brisk Wind Advisory for PKZ200-PKZ215-PKZ220-PKZ225-PKZ230.
&&

$$

EB JAN 19
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