Gale Warning 127, NWS Anchorage, AK

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
552 AM AKST Sat Feb 19 2022

.ANALYSIS AND UPPER LEVELS...

A large low pressure system near 47N 168E is moving northeastward.
A weak trough of low pressure currently extends across the Gulf of
Alaska. An upper level low currently over eastern Siberia and the
Bering Strait is slowly drifting westward. The jetstream currently
extends northeastward from the subtropical west Pacific to the
eastern Aleutian Islands and then extends eastward across the
southern Gulf of Alaska into Southeast Alaska and British
Columbia.

Closer to the surface, radar shows isolated showers moving
eastward across the northern Gulf .

&&

.MODEL DISCUSSION...

Models are generally in good agreement with respect to the
placement and intensity of synoptic scale features. The biggest
area of uncertainty continues to be precipitation type as subtle
differences in forecast 850 mb temperatures are observed. Subtle
differences in smaller scale phenomena are also apparent and this
can affect the temperature forecast and thus affect the
precipitation-type forecast.

&&

.AVIATION...
PANC...Conditions will mainly be VFR for this TAF period. IFR
conditions are likely between 20/07z and 20/10z as ceilings will
fall to near 700ft. Light winds will persist througout the period.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Today through Monday
Night)...

A quiet start to the forecast period will become more active
Monday morning and beyond as the next North Pacific storm moves
into Southcentral.

Southcentral is finally starting to see a break in the parade of
storms this weekend as upper level ridging builds into the
region. The skies have done a remarkable job at clearing, with
much of Anchorage, the Kenai, and Kodiak seeing more stars than
clouds this morning. Meanwhile lower cloud cover remains in place
for much of the rest of the area. It remains to be seen how well
the sun can work at the low stratus up in the Valley, but there is
at least some chance that the skies can clear up that way as well.
Any leftover precipitation over the Copper Basin will quickly end
this morning, leaving the entire area dry for much of the day.
Temperatures have been falling below freezing, so slick conditions
are likely this morning.

Tonight a weakening front will move over Kodiak Island during the
evening. Temperatures should be warm enough for mostly rain, but a
mix with snow can't be ruled out. Regardless, no accumulations are
expected. The front will continue shearing apart as it pushes into
the southern Kenai Peninsula late tonight, but any shower activity
will be very light and short-lived around Homer. There is high
confidence no measurable precipitation will encroach much further
north Sunday morning. Unfortunately, despite the lack of
precipitation, cloud cover will more successfully encroach on the
area, resulting in an overcast, but dry day for most of
Southcentral on Sunday.

On Sunday night, a second front will move into Kodiak. Unlike the
first front, this will be the start of a prolonged period of
occasionally heavy precipitation for not just Kodiak, but for all
of Southcentral. Unfortunately, there remains considerable
uncertainty as to the track of the storm and the wind pattern
around the stalled front, which looks to set up along Cook Inlet.

It's looking increasingly likely that there will be a Turnagain
Arm wind for much of the day on Monday, but it's not as clear as
to whether or not that wind will bend into Anchorage. Temperatures
will once again be right on the borderline with this event, as a
considerable amount of warm air is funneled north along the front
above the surface. As of now generally we are looking at the 31
to 36 degree range for much of Southcentral, which if we are at
the higher end, will be a mostly rain event, whereas temperatures
closer to freezing could result in either a cold rain or a wet,
heavy-consistency snow that mostly melts on contact with road
surfaces, especially Monday afternoon. As usual, the further south
you go the warmer you get. Since a very general consensus of the
guidance has the front aligned north-south along Cook Inlet into
the Susitna Valley, lots of warm air being funneled north along
the front most likely will result in mostly rain from Anchorage
south, while heavy wet snow is likely in the Susitna Valley where
cold air is notoriously difficult to displace.

On Monday night into early Tuesday morning, a strong low
supported by a strong upper level shortwave will track into
Southcentral along the front. As the low approaches and moves
through, it will enhance the precipitation rates area-wide, but
the track remains highly uncertain. The closer to the coast the
low tracks, the more likely there will be widespread snow, and
vice versa. A small change in track makes a large difference for
communities along it, so once again it can't be said with any
certainty how precipitation type will work out. The low tracking
through during the overnight should help support a snowier
solution, but track is far more important. Precipitation will
quickly end from west to east Tuesday morning.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3 - Today
through Tuesday)...

An active pattern continues for Southwest through Tuesday. A
series of fronts will move through the region this weekend, with
the first front set to track across later today. Precipitation
will begin as snow across northern and interior Bristol Bay and
the Kuskokwim Delta this afternoon. There will be a quick
transition to rain, with a possible brief period of freezing rain,
as the front passes over these areas this evening. Another much
warmer front is expected to move into the region during the day on
Sunday, bringing widespread rain with temperatures in the mid to
upper 30s. Freezing rain potential with this feature will move
into the Lower Kuskokwim Valley, namely for the villages from
Aniak east. Please see the current Special Weather Statement for
more details.

By Sunday night, another frontal system aims for the northwestern
part of the Kuskokwim Delta and will prolong precipitation in this
area. Conditions finally look to clear up from south-north across
the region as the front pushes northward. Another system will
track northward across Southwest from the western Gulf/north
Pacific Monday morning into Tuesday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3 -
Today through Tuesday)...

An active pattern persists for the Bering Sea and Aleutians
through Tuesday. First, a surface low remains nearly stationary
over the western Aleutians while its front spreads west-east
across the Bering as it pushes northward. A quick transition from
snow to rain is expected as the front passes through,
Precipitation will remain as snow for the northern Bering. Next,
a strong low pressure system moves from the north Pacific into the
central Bering. A front first crosses over the Aleutians early
Sunday, and then the associated storm force low tracks over the
central Aleutians shortly after. There is still some uncertainty
as to the exact track of this storm. Although the strongest winds
are still expected to occur between Adak and Unalaska, current
model solutions have the winds peaking later Sunday morning and
diminishing into late Sunday night. The low strength is also
depicted to be a bit weaker, so winds look like they will only
peak at storm force. The low center has shifted more to the east,
and this now puts Nikolski and Unalaska at the greatest risk for
seeing some of the strongest winds from this storm. As such, a
High Wind Watch will take effect late tonight and last through
Sunday afternoon for the eastern Aleutians.

Sunday afternoon into Monday, the storm force low and the
aforementioned stationary low join together to form one big low
pressure system over the central Bering. This new system elongates
and moves into the northern Bering by Tuesday morning. At the
same time, another front from the north Pacific moves across the
western and central Aleutians. The front pushes northeastward
across the Bering through Tuesday as the associated surface low
approaches the western Aleutians.

&&

.Marine (Days 3 through 5: Monday through Wednesday)...

Gulf of Alaska:

High pressure moves into the Eastern Gulf for Tuesday. A front
enters the Western Gulf and extends across the Northern Gulf
through Wednesday. Forecast guidance is good. Light winds yield to
gusty Southerly winds less than gale force moves across the Gulf
through Wednesday. An area of high end Easterly gales extends over
the Barren Islands and Kamishak Bay late Monday through
Wednesday. Seas to 12 feet with the front through Wednesday.

Bering Sea/Aleutians:

The weather pattern continues busy through Wednesday. A well
developed Central Bering low moves through The Bering Strait for
Tuesday. A strong front moves across the Aleutians and Bering
through Wednesday. Forecast confidence is good. The Central Bering
wind wrapped low has high end Southerly gales with areas of storm
force winds on its Eastern flank, diminishing Tuesday. Western
flank has Northerly gales, diminishing late Monday. Seas to 24
feet over the Central Bering, and to 20 feet on the Pacific side
of the Aleutians, subsiding late Monday. Widespread Southerly
gales with the front move into the Central Aleutians and Bering by
Wednesday. Seas building to 20 feet for Wednesday.

&&

.Long Term Discussion (Days 4 through 7: Thursday through Sunday)...

Upper level trough/ridge pattern continues through the long term.
Ridging over the State on Tuesday moves eastward through the late
week, meanwhile, longwave troughing extends over the Bering sea.
Solutions are hinting at the development of a surface low at the
base of the trough south of Kodiak Island/Southern AKPen. This
would bring active weather to Kodiak Island initially, and to the
North Gulf Coast later as the front moves northwards. Periods of
warmer air ahead of front may keep temperatures freezing in some
places, and precipitation type will continue to vary. There is
fair model agreement for the progression of the upper level waves
moving across the State through mid-week. Model spread begins to
grow beyond Wednesday with the approach of a North Pacific low.

&&
.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...High Wind Warning 187.
High Wind Watch 185.
MARINE...Storm Warning 170 173 174 175 412 413 414.
Gale Warning 155 165 171 172 176 177 178 179 181 185 411.
Heavy Freezing Spray Warning 185 411 412.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...ED
SOUTHCENTRAL ALASKA...JW
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AF
MARINE/LONG TERM...MK/KM

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
335 PM AKST Sat Feb 19 2022

AKZ152-155-161-201500-
Lower Kuskokwim Valley-Kuskokwim Delta-Bristol Bay-
Including the cities of Aniak, Sleetmute, Bethel, Hooper Bay,
Nunivak Island, King Salmon, Dillingham, Naknek, and Pilot Point
335 PM AKST Sat Feb 19 2022

...WINTRY MIX EXPECTED FOR SOUTHWEST ALASKA THROUGH THE WEEKEND...

A series of weak fronts will move through Southwest Alaska this
weekend, each bringing multiple types of precipitation. Snow has
developed this afternoon along the Southwest coast and is pushing
into the interior of Southwest in advance of the first front. A
brief period of freezing rain is possible for these areas Saturday
evening as warmer air moves overhead. Any ice accumulations are
expected to be less than five hundredths of an inch, with areas
between Togiak and Kipnuk and being the most likely to receive any
freezing rain. Impacts are expected to be minimal as winds will
become southerly on Sunday, warming temperatures above freezing
and transitioning remaining precipitation to all rain.

Another much warmer front will move into the region mid-day on
Sunday. This will produce widespread rain with temperatures in
the mid to upper 30s. The higher chance of freezing rain will
shift into the Lower Kuskokwim Valley, potentially bringing light
freezing rain to villages from Aniak east. Impacts are expected
to be minimal with all areas likely to be in the mid to upper 30s
by Monday; however, warm temperatures and rain may result in slick
conditions throughout the area by early next week as compacted
snow begins to melt.