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015
FXAK69 PAFG 062355
AFDAFG

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
355 PM AKDT Mon May 6 2024

.SYNOPSIS...
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Snow and blowing snow is causing reduced visibility from the
Bering Strait to Point Hope and east along the Brooks Range to
Atigun Pass. These conditions will improve late this evening as
winds decrease.

A band of rain and snow (with all snow above 2000 ft and north of
the Yukon River) that lies from Denali to Atigun Pass will move
to the Yukon River Bridge to Utqiagvik by 4am Tue, then diminish
from the south Tue morning. Expect 1-3 inches of snow from Finger
Mountain to Utqiagvik by Tue, heaviest in the Central Brooks
Range.

A second band will bring rain and snow to the SE Interior Tue,
spreading over the Tanana Yukon Uplands and the Dalton highway
north to Atigun Pass Tue night, and over the Northern Interior and
North Slope from Utqiagvik east on Wed, diminishing from the
south Wed night and Thu. Expect 1-2 inches of snow above 2000 ft
and north of the Arctic Circle with this Tue PM into Wed and could
see 2-4 inches in the White Mountain above 2000 ft. Could see 2-4
inches over the North Slope from Utqiagvik east Tue night into
Thu. Wed night and Thu could see rain/snow mix along south slopes
of the Alaska Range, with rain and snow moving over the SE
Interior Thu night and Fri.

Temperatures are well below normal along the West Coast will
moderate slowly from Wed into the weekend. Temperatures near
normal on the North Slope will above normal from Thu through the
weekend. Temperature in the Interior are well below normal today,
will warm slightly but remain below normal on Tue, warm to near
normal on Wed and then warm above normal on Thu before cooling
back to normal Fri into the weekend.

Moderate southerly Chinook winds are expected to develop along the
Alaska Range Wed night and continue into Thu AM before weakening
Thu PM.

At the surface...
An Arctic front stretches from Eagle to Huslia to Togiak will
move to Arctic Village to Ambler to King Salmon by 4pm Tue, and to
Barter Island to Noatak to Illiamna by 4pm Wed. A polar occluded
front from Denali to Arctic Village will move to Anaktuvuk Pass to
Utqiagvik by 4am Tue then weaken.

High pressure north of the Arctic Coast of AK will persist into
Wed then weaken.
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&&

.DISCUSSION...
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Models initialize well aloft at 12Z. Models show similar
solutions aloft through 4am Tue, then the GFS become an outlier
moving the Low aloft NW across the Interior more quickly, weaker
and further NW than the other models. The ECMWF and Canadian
models have pretty good similarity aloft through Thu with the low
aloft moving to near Utqiagvik by 4pm Thu, with a short wave
extending east to Inuvik. Prefer a blend of the ECMWF and
Canadian Models for features aloft through Thu, and will note that
the 12Z NAM was fairly similar as well.

A short wave trough from Denali to Arctic Village will move to
Anaktuvuk Pass to Utqiagvik by 4am Tue then move NW.

A second short wave trough over SE AK will move over the SE
Interior by 4am Tue, and to Fairbanks to Old Crow by 4pm Wed.

The long wave pattern consists of a deep trough over Western
Alaska and a strong ridge over Western Canada. This pattern
retrogrades over the next several days as the long wave trough
moves over the Bering and Western AK by Wed and the ridge builds
over NE AK. This will cause SE flow with several short waves
moving NW across Interior AK. Each of the short waves will bring
several inches of snow or mixed rain and snow to the Interior and
North Slope through Wed, with moderate strength southerly chinook
winds developing across the Alaska Range Wed night and continuing
into Thu AM. This will cause a drying and warming trend over the
SE Interior Wed into Thu.

850 MB temperatures range from +2C along the ALCAN Border to -20C
along the West Coast. Temps increase to -10C along the West Coast
with 0C pushing west over the Eastern Interior on Tue. By Wed the
West Coast increases to -6C to -8C while the Interior remains
about the same. Wed night and Thu will mainly see warming over the
SE Interior in the Chinook area.

With precipitation, models show similar solutions through 4am
Tue, then the GFS moves the precip with the second short wave NW
more quickly than the other models. Prefer the slower ECMWF,
Canadian and NAM precip solutions. Will use a blend of the NAM,
ECMWF and Canadian for precip areal coverage and amounts.
Highlights include: A band of snow from the Bering Strait to Point
Hope will move west of the Coast tonight. A band of rain and snow
with the first short wave (with all snow above 2000 ft and north
of the Yukon River) that lies from Denali to Atigun Pass will move
to the Yukon River Bridge to Utqiagvik by 4am Tue, then diminish
from the south Tue morning. Expect 1-3 inches of snow from Finger
Mountain to Utqiagvik, heaviest in the Central Brooks Range. The
second short wave will bring rain and snow to the SE Interior Tue,
spreading over the Tanana Yukon Uplands the the Dalton highway
north to Atigun Pass Tue night and over the Northern Interior and
North Slope from Utqiagvik east on Wed, diminishing from the
south Wed night and Thu. Expect 1-2 inches of snow above 2000 ft
and north of the Arctic Circle with this Tue PM into Wed and could
see 2-4 inches in the White Mountain above 2000 ft. Could see 2-4
inches over the North Slope from Utqiagvik east Tue night into
Thu. Wed night and Thu could see rain/snow mix along south slopes
of the Alaska Range, with rain and snow over the SE Interior Thu
night and Fri.

At the surface at 15Z, Models verify well on most features. The
NAM, ECMWF and Canadian models keep the surface low over the SE
Interior a bit deeper than the GFS on Tue and then keep it so as
they move it to near Demarcation Point on Wed. Prefer a blend of
the 12Z NAM and Canadian models for winds. Highlights include:
NE winds 15-30kt from the Bering Strait to Point Hope and along
the Brooks Range east to Atigun Pass will decrease tonight. South
winds increasing to 30 mph gusting to 50-60 mph through Alaska
range Passes Wed night and Thu AM, then decreasing Thu PM.

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

.FIRE WEATHER...
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Cool and wet conditions continue today into Wed AM, with drying
and warming Wed along with southerly Chinook winds gusting to 50
mph along the Alaska Range Wed night into Thu AM. At this time it
looks like strong winds will be late Wed night and early Thu AM so
not anticipating Red Flag conditions at this time, but need to
keep an eye on Wed night and Thu.
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&&

.HYDROLOGY...
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As of mid-day Sunday, not much change has been reported and the
Yukon River breakup front is roughly 30 miles upstream of Circle,
near Coal Creek. There is a 20 mile run of dense ice above the
breakup front. Residents of Circle should be aware that the
breakup front is approaching. No overbank flooding has been
reported yet. However as the breakup front moves downstream, it is
likely that small jams may form and release, leading to
fluctuating water levels and potential minor or moderate flooding.
There have been now reports on changes to this situation from
today.
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&&

.AFG WATCHES/WARNINGS/ADVISORIES...
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AK...Winter Weather Advisory for AKZ801-809-812-820-821.
     Flood Watch for AKZ833.
PK...Heavy Freezing Spray Warning for PKZ801-816-850.
     Heavy Freezing Spray Warning for PKZ802.
     Heavy Freezing Spray Warning for PKZ803-852.
     Heavy Freezing Spray Warning for PKZ804.
     Small Craft Advisory for PKZ805-850.
     Heavy Freezing Spray Warning for PKZ805-810.
     Gale Warning for PKZ806-810.
     Heavy Freezing Spray Warning for PKZ806-851.
     Brisk Wind Advisory for PKZ807-817-854.
     Gale Warning for PKZ811-856-857.
     Brisk Wind Advisory for PKZ812.
     Small Craft Advisory for PKZ816-851.
     Brisk Wind Advisory for PKZ853.
     Brisk Wind Advisory for PKZ858.
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&&

$$

JB