Blizzard in Alaska, January 13, 2021

Northern Alaska Forecast Discussion
National Weather Service Fairbanks AK
246 PM AKST Tue Jan 12 2021

.SYNOPSIS...
The same pattern continues as the storm track over the Pacific
continues to send weak disturbances inland north of the Alaska
Range, with one currently tracking westward along the Brooks
Range. A tight pressure gradient continues through the Bering
Strait and along the North Slope with areas of blowing and
drifting snow. For the Interior, weak ripples of energy will bring
light snow threats for the next few days, although most of this
will north of the Tanana Valley as the strong easterly gradient
keeps things drier closer to the AK Range as the persistent
pattern remains.

&&

.DISCUSSION...

Upper Levels and Analysis...
A huge area of cyclonic flow aloft dominates the entire Bering
Sea, North Pacific, Gulf of Alaska, and the Mainland. The main low
center remains around Bristol Bay with the upper center around
499 dam. Satellite imagery shows a strong low along the eastern
periphery of the trough over the Alaska Panhandle with another
shortwave over the Central Brooks Range. The surface low center is
also over Bristol Bay at around 974 mb, but it is weakening, and
this will allow Bering Strait north winds to finally diminish
tonight. Finally, a moderately strong 1028 mb high over the Arctic
is pushing up against the North Slope, creating a moderate
strength easterly pressure gradient.

Model Discussion...
The numerical weather models are all pretty much the same with the
general synoptic pattern. However, as usual, they differ with the
smaller scale details, and in this case, they differ the most with
the timing of a series of shortwave troughs which will move into
the Interior from the Gulf of Alaska. Given this type of pattern,
a blend of models was favored, however, the drier of the model
solutions was given much stronger weighting for the Tanana Valley
which has been quite dry lately owing to the persistent Tanana
Valley Jet.

Central and Eastern Interior...
Mostly dry weather will dominate the pattern as a persistent
Tanana Valley Jet continues near the AK Range. Southerly flow
aloft will also inhibit precipitation. The next chance comes
tonight and Wednesday as a weakening shortwave trough from the
Gulf rotates north, bringing light snow chances from the White
Mountains northward, with any accumulations looking paltry given
the dry air in place. A stronger wave impinges on the region
Thursday night and Friday, bringing a strong northeast gradient.
This will blow over the higher summits along the Dalton and Steese
where some blowing and drifting snow is likely. This front will
eventually move inland bringing a better chance for snow north of
the Tanana Valley on Friday.

West Coast and Western Interior...
Strong north winds over the Bering Strait and along the coast will
finally abate tonight as the gradient quickly slackens. Light snow
showers from Norton Sound north and across the Kobuk
Valley/Selawik Valley will deposit a couple inches of snow before
exiting Wednesday. Quiet weather continues through Wednesday night
before another round of strong north winds develops over the coast
Friday.

North Slope and Brooks Range...
Strong easterly winds and blowing snow will continue through early
tomorrow before the gradient and winds begin to slacken off over
the eastern half of the Arctic. The gradient will remain strong,
however, farther west, especially from Point Hope to Point Lay
where winds will gust into the 45 mph range. Expect the worst
visibility reductions there. Threats for blowing snow will
redevelop out east again on Friday as the gradient tightens back
up in response to a shortwave trough crossing the AK Range and
moving north.

Extended Forecast Days 4-7...
Beginning the extended period forecast on Friday evening, there
will be a shortwave trough crossing the AK Range into the
Interior, bringing the threat for snow from the West Coast to the
ALCAN as the elongated front interacts with the ridge in place.
There is a lot of uncertainty with this system, but currently the
pattern looks most favorable for snow the farther one is from the
AK Range. The southerly flow aloft combined with a Tanana Valley
Jet will severely limit the threat for Fairbanks south, but it is
still too far out to say for certain. After that, the pattern gets
real messy as another strong low moves up into the Gulf of Alaska
for the weekend. This will likely not be much different than the
current weather with above average temps and mostly dry for the
Interior, but next week, things may change as the flow looks to
shift from a Gulf of AK storm track to a Bering Sea storm track.
Stay tuned...

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

&&

.AFG WATCHES/WARNINGS/ADVISORIES...

Winter Weather Advisory for AKZ201-AKZ202-AKZ203-AKZ204.

Gale Warning for PKZ220-PKZ225-PKZ230-PKZ235-PKZ240-PKZ245.

Brisk Wind Advisory for PKZ210.

&&

AHSENMACHER JAN 21