Brisk Wind Advisory 8, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
514 PM AKST Fri Jan 7 2022

.ANALYSIS AND UPPER LEVELS...

The 250 mb upper level pattern shows a strong ridge over eastern
Russia, through the Bering Strait, and into Southwest Mainland
Alaska. A strong upper level low at this level is over the
Northwest Territories and heading toward the Yukon. This puts a
jet streak in the strong northerly flow over most of mainland
Alaska and into Southcentral. This cold pattern will begin to give
way this weekend to the system that can be seen well south of the
state on satellite. The low just a ways south of the Alaska
Peninsula will not make much more headway, but the low developing
near 40N 155W will. The development of this new low can be seen
on satellite loop this afternoon and will continue to develop as
it heads northward. Unusually clear skies over the northern half
of the Bering Sea show the ice edge very distinctly. It is
interesting that there are no cloud streamers developing over the
warmer waters of the Bering Sea just off the ice edge, but that is
likely due to the air mass in that area being relatively warm
compared to the rest of the state.

&&

.MODEL DISCUSSION...
Models are now coming into much better agreement with the main
problem area which was with the low moving toward Kodiak on
Saturday night into Sunday. Specifically, the 18Z NAM run is now
aligned with the 12Z GFS run which is good as the GFS has shown
good run- to-run consistency. This makes it likely that the
GFS/NAM solution is good which increases confidence in the Kodiak
Island forecast and especially the precipitation type there for
Saturday night into Sunday.

&&

.AVIATION...
PANC...Increasing northerly winds should keep fog/stratus from
redeveloping overnight, though a brief period of fog at the
terminal is possible before midnight. A mid- level cloud deck
moving in from the east late tonight should also keep out more fog
so predominantly VFR conditions are expected.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 to 3)...

A strong inversion this morning allowed for very cold
temperatures to stay near the surface and freezing fog to linger
near Anchorage until this afternoon. This also delayed some of the
mixing of the winds aloft to the surface over the Matanuska
Valley. An observation southwest of Talkeetna hinted at what could
be expected over the Matanuska Valley as temperatures warmed
about 36 degrees with any winds breaking through this inversion.
Generally northerly flow aloft this afternoon with a tightening
gradient as a trough descends and elongate westward as it crosses
Southcentral. Coupled with a tight surface pressure gradient along
the mountains, gap winds were favorable in the typical wind
prone locations along the coast. As this upper trough passes
south over the Matanuska Valley, winds will mix to the surface and
temperatures will increase into the teens. Winds and temperatures
have increased through Sutton late this morning and have made it
north of Palmer to Wasilla so far this afternoon. Winds are
expected to increase through the afternoon and peak tonight before
diminishing after midnight. Winds will ramp up again Saturday
afternoon.

Meanwhile, a North Pacific low will lift a trough north into the
Gulf by Sunday morning. A short wave ahead of the front may bring
a chance of light snow to Kodiak on Saturday. On Sunday however,
plenty of warm air and moisture will advect northward and change
snow to rain for Kodiak and continue towards the Gulf coast
through Sunday. By Sunday afternoon, a storm force barrier jet
will set up along the northwestern Gulf coast and Shelikof Strait.
The barrier jet could extend along the northern Gulf and bring at
least gales into Prince William Sound. Models have come into
better alignment this afternoon for snow to arrive along the Gulf
coast around noon on Sunday and the low to track more west.
However, the overall placement and track of the low could change
going into Sunday evening. While this system may bring plenty of
snowfall along the coast and the mountains, further inland such as
the leeside of the Kenai and Chugach Mountains, snow amounts will
be much less due to a downsloping, thus limiting the amount of
moisture available away from the coast.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Day 1 through 3: Tonight
through Monday)...

A very cold Arctic high pressure remains stagnant over the area
and will continue to bring dry and windy conditions. Due the
aforementioned high pressure, storm systems are being pushed to
the south and staying mostly across the southern Bering and
Aleutian Island Chain. A slight chance for some light snow exists
around Dillingham and Bristol Bay areas as a shortwave passes
over Saturday afternoon into Sunday.

Temperatures will continue to decrease tonight as another shot of
cold Arctic air is pushed into the area from the interior. This
will reinforce the hold the Arctic air already has in place over
the area. With storm systems moving across the Chain and the
reinforced high pressure over Alaska, pressure gradients will
continue to be tightened and result in windy conditions through
Sunday. Models agree that an upper-level low will move southwest
Saturday afternoon through Sunday and will yield to enough upper-
level support to give way to stronger winds Saturday afternoon
through Sunday. Sustained northeasterly winds of 25 to 30 mph are
expected across the Kuskokwim Delta with gusts upwards of 40 mph
especially Saturday afternoon through Sunday. Gusty winds are also
expected across Bristol Bay but winds aren't expected to be as
strong. With high winds and cold temperatures, expect bitterly
cold wind chills Saturday night to Sunday that could be as low as
35 below zero near the Kuskokwim Delta.

A pattern change will begin Sunday due to a fairly strong storm
system moving northeastward from the North Pacific to around
Kodiak Island. This will give way to increasing cloud cover,
warming temperatures, and chances for snow- with the potential for
downsloping on the leeward side of the mountains depending on the
exact track of the low leading into the work week.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Day 1 through 3:
Tonight through Monday)...

Multiple lows will move through the Bering and Aleutian Islands
in the coming days. A low that is located over the North Pacific,
just southeast of Adak, has its front extending into the
Aleutian Islands while its center remains offshore and south of
the coastal marine zones. As a result, gale force winds have
developed and will continue through tonight. The ridge of cold
arctic air located over Mainland Alaska, will begin to push across
the Bering Saturday into Sunday. This will give way to increasing
winds due to the tightening of pressure gradients. As a result,
widespread gale force winds and increased wave heights will be
apparent. As cold air and high winds move over the Bering,
freezing spray will return to the area with heavy freezing spray
along/ near the ice edge. As Monday approaches, freezing spray
will extend further east into the Bering with heavy freezing spray
continuing to stay mainly north of 57N and E of 174W and along
the ice edge.

&&

.MARINE (Days 3 through 5 - Monday through Wednesday)...

Gulf of Alaska: A well developed low near Kodiak Island moves
into Southwest Alaska and dissipates for Tuesday. Its front
extends across the North Gulf Coast through Wednesday. Forecast
confidence is fair with the frontal development. Widespread gusty
winds with areas of gales over the Northern Gulf and Cook Inlet.
diminishes late Monday. Seas to 24 feet across the Northern Gulf,
subsiding Tuesday.Slight risk of freezing spray over Cook Inlet
Monday.

Bering Sea: High pressure retreats over the Russian Far East
through Wednesday. A well developed North Pacific low moves over
the Central Aleutians through Wednesday. Forecast confidence is
fair with the low track and timing. Widespread gusty winds with
areas of gales over the Bering and Central Aleutians diminishes
Wednesday. Seas to 18 feet, subsiding Tuesday. Slight risk for
freezing spray over Western Bering open waters.

&&

.LONG TERM FORECAST (Days 4 through 7/Tuesday through Friday)...

Upper level ridging over the Mainland tracks southwestward as
upper level troughing digs down across the state, extending into
the Bering Sea. Simultaneously, a system over the Aleutians pushes
its front into the Gulf, generating periods of significant
precipitation, namely along the North Gulf Coast and Kodiak
Island, mid-week. Winds may pick up as pressure gradients tighten,
especially through bays and passes such as Resurrection Bay and
Passage Canal. A North Pacific low moves towards the AKPen towards
the end of the week, its front pushing the northern Gulf by
Thursday. Periods of heavy rain or snow are possible along the
North Gulf Coast, with lighter precipitation possible elsewhere
across Southern Alaska as we approach the weekend. The orientation
of the trough as it pushes onshore may allow for downsloping to
occur over western Anchorage and western Kenai.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Special Weather Statement 111.
MARINE...Storms: 130.
         Gales: 119, 120, 127, 128, 131, 132, 136, 137, 138, 139 150,
                155, 165, 170, 172, 173, 174, 175, 176, 177, 179, 185,
                411, 412, 413, 414.
         Heavy Freezing Spray: 119, 126, 127, 128, 130, 139, 141, 165,
                179, 185, 412, 414.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...VR
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...NS
MARINE/LONG TERM...MK/KM