Winter Storm Watch 7, NWS Anchorage, AK

756 
WWAK42 PAFC 271333 CCA
WSWALU

URGENT - WINTER WEATHER MESSAGE...CORRECTED
National Weather Service Anchorage AK
433 AM AKST Sat Nov 27 2021

AKZ185-280200-
/O.COR.PAFC.WS.A.0007.211128T0800Z-211129T2000Z/
Eastern Aleutians-
Including the cities of Unalaska and Nikolski
433 AM AKST Sat Nov 27 2021

...WINTER STORM WATCH IN EFFECT FROM THIS EVENING THROUGH MONDAY
MORNING FOR UNALASKA AND NIKOLSKI...

* WHAT...Blizzard conditions possible. Total snow accumulations of
  1 to 7 inches possible. Easterly winds of 40 to 50 mph with
  gusts up to 60 mph are expected. 

* WHERE...Eastern Aleutians including Unalaska and Nikolsi.

* WHEN...Tonight through Monday morning.

* IMPACTS...Plan on slippery road conditions. Areas of blowing
  snow could result in visibility as low as one quarter mile at 
  times.

* ADDITIONAL DETAILS...A strong front will bring snow and blowing
  snow starting Saturday night into Monday morning. Strong winds
  from the front combined with cold polar air could potentially
  generate blizzard conditions over the warned area. Forecast
  models are still uncertain on the exact storm track, due to the
  high uncertainty a watch has been issued at this time. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch for blizzard conditions means there is a
potential for falling and/or blowing snow with strong winds and
extremely poor visibilities. This can lead to whiteout conditions
and make travel very hazardous. 

&&

$$

http://www.weather.gov/afc

741 
WWAK42 PAFC 271621 AAA
WSWALU

URGENT - WINTER WEATHER MESSAGE...UPDATED
National Weather Service Anchorage AK
721 AM AKST Sat Nov 27 2021

AKZ185-280200-
/O.CON.PAFC.WS.A.0007.211128T0800Z-211129T2000Z/
Eastern Aleutians-
Including the cities of Unalaska and Nikolski
721 AM AKST Sat Nov 27 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM THIS EVENING THROUGH
MONDAY MORNING...

* WHAT...Blizzard conditions possible. Total snow accumulations 
  of 1 to 7 inches possible. Easterly winds of 40 to 50 mph with 
  gusts up to 60 mph are expected.

* WHERE...Eastern Aleutians including Unalaska and Nikolski.

* WHEN...Tonight through Monday morning.

* IMPACTS...Plan on slippery road conditions. Areas of blowing 
  snow could result in visibility as low as one quarter mile at 
  times.

* ADDITIONAL DETAILS...A strong front will bring snow and 
  blowing snow starting Saturday night into Monday morning. 
  Strong winds from the front combined with cold polar air could 
  potentially generate blizzard conditions over the warned area. 
  Forecast models are still uncertain on the exact storm track, 
  due to the high uncertainty a watch has been issued at this 
  time.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch for blizzard conditions means there is a
potential for falling and/or blowing snow with strong winds and
extremely poor visibilities. This can lead to whiteout conditions
and make travel very hazardous.

&&

$$

http://www.weather.gov/afc

122 
WWAK42 PAFC 271948
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
1048 AM AKST Sat Nov 27 2021

AKZ185-280200-
/O.CON.PAFC.WS.A.0007.211128T0800Z-211129T2000Z/
Eastern Aleutians-
Including the cities of Unalaska and Nikolski
1048 AM AKST Sat Nov 27 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM THIS EVENING THROUGH
MONDAY MORNING...

* WHAT...Blizzard conditions possible. Total snow accumulations 
  of 1 to 7 inches possible. Easterly winds of 40 to 50 mph with 
  gusts up to 60 mph are expected.

* WHERE...Eastern Aleutians including Unalaska and Nikolski.

* WHEN...Tonight through Monday morning.

* IMPACTS...Plan on slippery road conditions. Areas of blowing 
  snow could result in visibility as low as one quarter mile at 
  times.

* ADDITIONAL DETAILS...A strong front will bring snow and 
  blowing snow starting Saturday night into Monday morning. 
  Strong winds from the front combined with cold polar air could 
  potentially generate blizzard conditions over the warned area. 
  Forecast models are still uncertain on the exact storm track, 
  due to the high uncertainty a watch has been issued at this 
  time.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch for blizzard conditions means there is a
potential for falling and/or blowing snow with strong winds and
extremely poor visibilities. This can lead to whiteout conditions
and make travel very hazardous.

&&

$$

http://www.weather.gov/afc

509 
WWAK42 PAFC 280007
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
307 PM AKST Sat Nov 27 2021

AKZ185-281400-
/O.EXT.PAFC.WS.A.0007.211128T1500Z-211129T2000Z/
Eastern Aleutians-
Including the cities of Unalaska and Nikolski
307 PM AKST Sat Nov 27 2021

...WINTER STORM WATCH NOW IN EFFECT FROM SUNDAY MORNING THROUGH
MONDAY MORNING...

* WHAT...Blizzard conditions possible. Total snow accumulations 
  of 1 to 7 inches possible. Easterly winds of 40 to 50 mph with 
  gusts up to 60 mph are expected.

* WHERE...Eastern Aleutians including Unalaska and Nikolski.

* WHEN...From Sunday morning through Monday morning.

* IMPACTS...Plan on slippery road conditions. Areas of blowing 
  snow could result in visibility as low as one quarter mile at 
  times.

* ADDITIONAL DETAILS...A strong front will bring snow and blowing
  snow starting early Sunday morning into Monday morning. Strong 
  winds from the front combined with cold polar air could 
  potentially generate blizzard conditions over the warned area. 
  Due to model uncertainty with exact storm track, a watch has 
  been issued at this time. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Watch for blizzard conditions means there is a
potential for falling and/or blowing snow with strong winds and
extremely poor visibilities. This can lead to whiteout conditions
and make travel very hazardous.

&&

$$

http://www.weather.gov/afc

920 
WWAK42 PAFC 280610
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
910 PM AKST Sat Nov 27 2021

AKZ185-281400-
/O.UPG.PAFC.WS.A.0007.211128T1500Z-211129T2000Z/
/O.NEW.PAFC.BZ.W.0017.211128T1800Z-211129T1800Z/
Eastern Aleutians-
Including the cities of Unalaska and Nikolski
910 PM AKST Sat Nov 27 2021

...BLIZZARD WARNING IN EFFECT FROM 9 AM SUNDAY TO 9 AM AKST MONDAY...

* WHAT...Blizzard conditions expected. Total snow accumulations of
  4 to 8 inches. East to northeast winds 30 to 45 mph with gusts 
  as high as 60 mph.

* WHERE...Eastern Aleutians, including Unalaska and Nikolski.

* WHEN...From 9 AM Sunday to 9 AM AKST Monday.

* IMPACTS...Plan on slippery road conditions. Widespread blowing
  snow will cause whiteout conditions at times.

* ADDITIONAL DETAILS...The worst conditions are expected Sunday
  afternoon and evening. The snowfall will then become showery on
  Monday. Gusty northerly winds and snow showers with reduced 
  visibilities in blowing snow will likely linger all the way 
  through Tuesday evening. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Blizzard Warning means severe winter weather conditions are
expected or occurring. Falling and blowing snow with strong winds
and poor visibilities are likely. This will lead to whiteout
conditions, making travel very hazardous. If you must travel,
have a winter survival kit with you. If you get stranded, stay
with your vehicle. 

&&

$$

AKZ181-281400-
/O.NEW.PAFC.WW.Y.0056.211128T2100Z-211129T1800Z/
Alaska Peninsula-
Including the cities of Cold Bay and Sand Point
910 PM AKST Sat Nov 27 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM NOON SUNDAY TO 9 AM
AKST MONDAY...

* WHAT...Snow expected. Total snow accumulations of 1 to 8 
  inches. Winds gusting as high as 55 mph.

* WHERE...Alaska Peninsula.

* WHEN...From noon Sunday to 9 AM AKST Monday.

* IMPACTS...Plan on slippery road conditions. Areas of blowing
  snow will reduce visibilities to one half mile or less at 
  times.

* ADDITIONAL DETAILS...The worst conditions are expected along the
  Bering side Sunday afternoon and evening, where the heaviest
  snow and strongest winds will be. The snowfall will then become
  showery on Monday as winds shift around to the north. Snow
  showers and reduced visibilities in blowing snow will likely
  linger through Tuesday night, especially along the Bering side. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

&&

$$

http://www.weather.gov/afc

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
431 PM AKST Fri Nov 26 2021

.ANALYSIS AND UPPER LEVELS...

Broad cyclonic flow continues across much of Southwest and
Southcentral Alaska, with northwest flow over the Aleutians.
This pattern continues to usher in very cold air across the
region. Readings range from the 20s and low 30s along the
Southcentral coastline and down the Aleutian chain, to the
teens along the Bering Sea coast, to the single digits above
zero in the Anchorage area to the single digits and teens
below zero elsewhere.

The broad cyclonic and northwest flow over the Bering and the
cold temps are creating areas of mainly light snow to favored
areas around the region.

A low pressure system continues to sit over Prince William Sound
bringing bands of heavier snow to both the Prince William Sound
area and favored areas on the Kenai Peninsula.

&&

.MODEL DISCUSSION...

Guidance remains in reasonably good agreement with the placement
and intensity of synoptic scale features at both the surface and
in the upper levels through the weekend. The main area of
uncertainty continues to be with the handling of the mesoscale
convective snowbands in Prince William Sound and Cook Inlet.
Overall forecast confidence is above average on the broad scale
but exact localized snow amounts remains a significant forecast
challenge and forecast confidence is extremely low in this area.

&&

.AVIATION...
PANC...VFR conditions and light winds will persist

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 to 3/Tonight
through Monday)...

Brutally cold temperatures and cyclonic flow continue over
Southcentral. There is closed low in the upper levels (at 500 mb)
that is currently north of Talkeetna and there is a broad area of
troughing over the mainland that extends into the Gulf of Alaska.
At the surface, there is a low near Montague Island. On Saturday,
a reinforcing shortwave will round the base of the upper trough
and move over the Alaska Peninsula. As this major shortwave digs
southeastward, the position of the closed low will modify
slightly. However, this pattern will continue to yield below
normal temperatures across Southcentral. More snow is expected for
portions of Cook Inlet and Prince William Sound this weekend.
Monday a new North Pacific low with an estimated intensity of 964
mb - 965 mb will approach Kodiak and the western Gulf of Alaska.
The global models all depict this system but the exact track of
the surface low remains relatively uncertain at this time.

&&

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

Interior Southwest Alaska will remain mostly dry and cold over
the next few days as low pressure to the east continues to pull
cooler and drier air southward. Low temperatures have been
challenging to forecast, with patchy clouds often limiting the
amount of radiational cooling. With that being said, Friday night
and Saturday night will be cold with interior temperatures in the
teens below zero. Some areas could see overnight lows drop into
the 30s below zero with Aniak potentially hitting 40 below zero
tonight. Of course this is highly dependent on skies remaining
clear or with minimal cloud cover. Sunday overnight lows will be
slightly warmer and Southwest could see a very mild warming trend
through the beginning of next week.

Main concerns across Southwest entail wind and snow for coastal
regions. Northwesterly surface flow will transport moisture
immediately inland of the coast posing the potential for light
snow from Hooper Bay southward to Toksook Bay and Goodnews Bay.
Accumulations should be light but up to an inch may be experienced
locally. Low confidence also continues for the possibility of
freezing fog across the Kuskokwim Delta for the next few nights
should any lingering moisture get trapped at the surface.

As with the past several days intermittent snow and gusty winds
will persist across the Alaska Peninsula tonight into Saturday.
This will present periods of reduced visibility within light snow
showers. The pattern will begin to change by Sunday as a new area
of low pressure approaches the Alaska Peninsula. While still a
few days out, guidance suggest the potential for strong easterly
to northeasterly winds and potentially more snow as a front
tracks just south of the Alaska Peninsula Sunday into Monday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3:
Tonight through Mon afternoon)...

High pressure and cold air remain entrenched over the Bering Sea
this evening. A complex of smaller waves of low pressure west of
the Aleutians are expected to begin consolidating tonight, though
eastward progress of low pressure will be limited by high pressure
over the Bering. Into Saturday low pressure will be aided by a
passing shortwave trough south of the Aleutians. As these two
features phase with each other, more noticeable eastward progress
will occur. This will be followed by a third wave of low pressure
lifting south of the Eastern Aleutians, helping to amplify the
original low even further. The end result will be the development
of a potent low pressure system tracking immediately south of the
Aleutians preceded by a front draped over or just south of the
Eastern Aleutians/Alaska Peninsula by Sunday. Expectations are
for widespread gale to potential storm force easterly winds to
materialize north of the low and along the front. 20 foot plus
seas are forecast to develop north of the Western Aleutians
Saturday night and expand southeastward across the Central and
Eastern Aleutians Sunday night.

Models have consistently struggled with the forecast and
discrepancies still abound. These discrepancies include how low
pressure evolves over the next 48 hours, further complicated by
the interaction of not one but two additional lows developing
over the North Pacific. Confidence in the finer details such as
the exact track of the lows and placement of frontal boundaries
is fairly low. This will determine which areas see the strongest
winds and heaviest precipitation, with some potential for blowing
snow (or blizzard conditions).

&&

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

Gulf of Alaska: Confidence is steadily increasing for a deep
North Pacific low to enter and cross over the Gulf as it tracks
mainly northeast towards the North Gulf Coast between Monday and
Wednesday. Winds around the low are expected to be at least gale
force, with storm force winds also possible along the low's
attendant front as it moves over the central Gulf on Monday and
approaches the Gulf coast at some point on Tuesday. Storm force
winds are also more likely where northeast flow is accelerated by
terrain near the southern Cook Inlet and Shelikof Strait, mainly
on Monday. Seas will also build to at least 20 ft over much of the
open Gulf waters, with highest seas coinciding with peak of
gale/storm force winds on Monday and Tuesday. Confidence is high
for at least gale force winds, with lower confidence remaining for
the low track.

Uncertainty increases further for Wednesday, with models diverging
on how quickly and where the low center reaches the Gulf
coastline. It currently appears winds will pick up once again up
to gales out of the west as the low potentially moves inland over
Southcentral on Wednesday. This will be especially likely where
cold air wrapping around the low from the northwest is
accelerated out of gaps along the Alaska Peninsula and Aleutian
Range.

Bering Sea/Southwest: A strong North Pacific low will be moving
south of the Aleutian Chain by the start of the period on Monday.
This will likely produce storm force winds along mainly the
central/eastern Aleutians and far southern Bering as it interacts
with modified Arctic air streaming southwest across the rest of
the Bering. Easterly gale force winds are expected farther north
across the rest of the southern/eastern Bering, becoming more
northerly as the low shifts towards the Gulf on Tuesday. Advection
of arctic air from the AK mainland over ice free waters will
continue to support heavy freezing spray from Monday to Tuesday,
with the most persistent and significant freezing spray closest to
the ice edge. As the initial system moves out of the region on
Tuesday, another low will enter the western Bering. Confidence for
this next system is lower at this time, but expect at least gales
near the low as it tracks across the western Bering/Aleutians
from Tuesday to Wednesday.

&&

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

The highly amplified longwave trough currently dominating much of
the state appears on track to re-assert itself for the first half
of the period. A deep North Pacific low moves into Southcentral
and merges with the existing upper trough over the mainland on
Tuesday. Upstream and to the west, a longwave ridge will progress
eastward into the Bering and amplify markedly between Tuesday to
Thursday. This will effectively further reinforce the longwave
troughing focused over mainland AK, allowing more Arctic air to
spill south into much of Southwest and, slightly later in the
week, Southcentral. This will unsurprisingly lead to mostly below
average temperatures continuing through at least Thursday for
inland locations, especially across the Southwest. The bigger
question will involve the fate of the aforementioned deep low in
the Gulf, with model differences persisting for the progression of
the system as it approaches the North Gulf Coast sometime between
Tuesday and Wednesday. Even with these differences, there remains
good potential for areas near Prince William Sound, Kodiak Island
and much of the Copper River Basin to see significant snowfall on
Tuesday/Wednesday as the low increasingly interacts with the
entrenched Arctic air in place farther inland. The low will begin
to slow as it occludes on Wednesday and eventually drift north
over Southcentral, potentially spreading more snow north along
with it into parts of the Mat-Su and Cook Inlet regions Wednesday
through Thursday morning.

A pattern change is looking more likely by the end of the work week,
with the Bering ridge possibly accelerating east into the western
mainland by Friday morning, finally bringing a halt to the
endless stream of Arctic air from the north. A strong front
associated with a potent Kamchatka low could impact much of the
Bering/Aleutians by this point as well, with strong winds,
rain/snow and much warmer temperatures moving in tow as it races
swiftly east late on Thursday and into Friday.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory 125.
MARINE...Storm Warning 177 178.
         Gale Warning 130 131 138 150 173 174 175 176.
         Heavy Freezing Spray Warning 121 127 129 130 131 137 138
                                   139 140 141 150 160 180 181.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...NR
SOUTHCENTRAL ALASKA...PS
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...BL
MARINE/LONG TERM...AS