Gale Warning 110, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
441 AM AKST Mon Jan 31 2022

.ANALYSIS AND UPPER LEVELS...

This morning on satellite imagery, there is a mature low north of
the Adak with an occluded front bisecting the Bering. There is a
second low south-southwest of Cold Bay. There is an area of high
pressure from the Bering Strait to Southcentral Alaska.
Additionally, freezing fog has been detected this morning over
portions of Cook Inlet, Knik Arm and Turnagain Arm. One sliver of
the jet is south of Cold Bay with a magnitude of 90 knots. There
is a second jet core over the northwest Pacific with a magnitude
of 160 knots. On ASCAT (Advanced Scatterometer) an area of gale
force winds that was detected west of the Pribilof Islands
associated with a 974 mb surface low.

&&

.MODEL DISCUSSION...

Models are in good agreement with the major synoptic features
through 36 hours. There are some minor differences with the
track and intensity of the next surface low in the northwest
Pacific which could impact the timing of precipitation. The main
forecast challenge will be the fog areas in Southcentral which is
an area where the models struggle. This is the second morning in a
row that fog has developed in Anchorage and Knik Arm.

&&

.AVIATION...

PANC...Again on satellite imagery (Nighttime Microphysics RGB)
fog/low stratus has developed over Knik Arm, Cook Inlet and
Turnagain Arm. Overnight, the fog has been ebbing and flowing
over PANC and at one point was down to 1/4 SM in visibility. The
fog activity over Southcentral Alaska is actively being monitored
and amendments will be made as needed. The current expectation is
that the fog will clear by 21z.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...

High pressure centered over the Interior of the state and
extending over Southcentral has cleared out skies and dropped
temperatures to their lowest levels in about two weeks over much
of the region. The exception is near Anchorage where persistent
fog has kept temperatures a little warmer. What is different from
yesterday morning for this upper Cook Inlet fog and stratus
regime is that yesterday it was almost all thick stratus with
almost no fog at sea level. This morning is it mostly fog with
much thinner stratus. This is allowing temperatures to be lower
than yesterday, but also may allow for a better chance for
clearing without the thick stratus. We shall see.

The next system will bring a front into Kodiak overnight which
will then overspread clouds across all of SOuthcentral by Tuesday
afternoon. There was some question yesterday how far north this
front will bring clouds and precipitation and it looks to be
farther north than what we were looking at yesterday.
Precipitation type will mostly just be an issue for Kodiak Island
overnight and perhaps the very southernmost tip of the Kenai
Peninsula Tuesday. For Kodiak it looks like a short burst of snow
early this evening will change to rain by late evening with the
rain heavy at times overnight. There is a lot of warm air aloft
with this system but the surface front itself will stall out over
the northern Gulf and keep a tight temperature gradient over the
north Gulf coast which should keep precipitation all snow along
the north Gulf coast through Wednesday.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2)...

Active weather is on its way to Southwest Alaska for the short
term. A low traveling northwards across the Bering drags
weak shortwaves along the Southwest Coast through today.
Resultant offshore flow will keep conditions cold and clear into
the evening hours. A second North Pacific low pushes towards the
southern Bering tonight, its front reaching the Bristol Bay coast
by this evening. A surge of warm air advects over the coast,
bringing areas of rain, freezing rain and possibly sleet.
Primarily, affected areas will be the Kuskokwim Delta, from Bethel
west, and Dillingham and areas north and west. Iliamna to Port
Heiden (including King Salmon) will likely see very little in the
way of snow or freezing rain as warmer air is expected to produce
plain rain for these areas. There is still some uncertainty
associated with the warm air mass, since a deeper warm layer will
promote more freezing rain versus a shallower layer that will
produce more sleet/rain- snow mix. Additionally, the more warm air
that is mixed in will result in less snowfall/snow accumulations.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 and 2)...

A series of lows move across the Bering through mid week. The
first of which is a vertically stacked low currently located just
west of Saint Paul. Lingering light rain showers remain over the
Eastern Aleutians, Southern AKPen, and the Pribilofs, with gusty
high end gale force winds along the northern Bering this morning.
The system moves off to the north by this evening. Two more North
Pacific lows push northwards on opposite ends of the Aleutians
tonight. The low near Shemya brings gale force winds and light
rain/snow showers to the Western Aleutians tonight and exits off
to the north by tomorrow morning. The second low is tracking
towards the AKPen, bringing a swatch of warmer air along its
front. Rain will be the primary precipitation type for the
Southern AKPen, with freezing rain along the Southwest Coast.
Gusty gale force winds are likely through Bristol Bay and out of
Shelikof Strait, but overall, precipitation remains the highest
impact for this system. A fourth system out of the North Pacific
moves over the Central Aleutians late Tuesday night and will bring
impactful weather to the Aleutian Chain by Tuesday night. Expected
impacts include rain or a rain/snow mix (all snow for the higher
elevations) and high end gale force winds along the front.

&&

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

Gulf of Alaska:

Gale force winds in the northern and western Gulf with localized
storm force winds in favored barrier jet areas diminish quickly on
Wednesday as a low exits into the eastern Gulf. The forecast for
Thursday and Friday is less certain with a series of systems
moving up from the Pacific. Portions of the Gulf may see another
round of gales on both days, with a similar but weaker barrier jet
setup possible on Thursday giving way to some potential for more
widespread westerly gales and gap winds Friday.

Bering Sea/Aleutians:

A strong low over the central Aleutians will produce widespread
gales across the central Bering/Aleutians Wednesday morning.
Storm force winds will also be likely near the center of the low.
Hurricane force gusts appear less likely now as the low is
expected to occlude and start weakening before reaching the
Aleutians. Southerly gale force gap winds can be expected east of
the low through the eastern Aleutians/AKPEN. Winds move with the
low into the western Bering late Wednesday into Thursday and
diminish below gale force by Thursday afternoon as the low exits
westward. Seas may exceed 20 ft in the vicinity of the low. The
northern Bering will likely see persistent northeasterly gales
before they decrease in coverage beginning Thursday afternoon.

Confidence is lower regarding the evolution of other features
which will impact wind and wave across the Bering/Aleutians.
A swath of easterly gales will be possible in the eastern Bering
and Bristol Bay from Wed afternoon into Thursday morning as
another low lifts northward across the AKPEN. By Friday morning,
another North Pacific low may impact the eastern Aleutians/AKPEN,
bringing the possibility for gales with some chance for storm
force winds and seas in excess of 20 ft near its center.

&&

.LONG TERM FORECAST (Days 4 through 7: Thursday through
Sunday)...

The prominent feature in the long term will be the 300 mb North
Pacific jet and placement south of the Aleutians; an ideal
location to generate multiple lows that will cycle through the
Bering. On Thursday, model solutions show a broad 500 mb trough
over the Bering and an upper level ridge over Siberia. A second
upper level ridge over the Alaska Panhandle early Thursday quickly
moves east as the first of several upper level shortwaves drive
across the Bering from west to east. Supported by the 300 mb jet,
multiple surface lows will lift from the North Pacific into the
eastern Bering Thursday into Friday, keeping an active weather
pattern in place for Southwest Alaska through the end of the
week. Southcentral will also see an active pattern with this setup
as each low gradually tracks eastward. By late Friday, model
solutions are hinting at the possibility for a deep fetch of
southerly flow lifting into Southcentral, however confidence is
low as agreement between solutions remains poor. In summary, the
synoptic setup is trending toward a more active pattern for the
southern half of the state for the end of the week and into next
weekend.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory 155 161.
MARINE...Storm 131. Gale 411 412 413 414 150 160 165 174 175 176
177 178 179 180 185 351 119 120 130 138 139. Heavy Freezing Spray
185.

&&

SYNOPSIS AND MODEL DISCUSSION...PJS
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...KM
MARINE/LONG TERM...KO