Blizzard Warning 16, NWS Anchorage, AK

814 
WWAK42 PAFC 100059
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
359 PM AKST Sat Dec 9 2023

AKZ161-111400-
/O.CON.PAFC.BZ.W.0016.231210T1200Z-231211T1400Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
359 PM AKST Sat Dec 9 2023

...BLIZZARD WARNING REMAINS IN EFFECT FROM 3 AM SUNDAY TO 5 AM
AKST MONDAY...

* WHAT...Blizzard conditions and heavy snow expected. Visibility 
  reduced to one quarter mile at times. Total snow accumulations 
  of 6 to 12 inches, with local amounts up to 18 inches 
  possible. Highest snow amounts over interior Bristol Bay, 
  including Koliganek and New Stuyahok. Northerly winds gusting 
  30 to 45 mph.

* WHERE...Bristol Bay.

* WHEN...From 3 AM Sunday to 5 AM AKST Monday.

* IMPACTS...Travel will be difficult. Blowing snow and heavy 
  snow will produce white-out conditions at times.

* ADDITIONAL DETAILS...Snow and blowing snow will develop first
  along the Alaska Peninsula late tonight then spread north and
  west across the remainder of the Bristol Bay area Sunday
  morning. There is some uncertainty on where the worst conditions
  will set up, but right now it looks to be from around King
  Salmon northward to New Stuyahok and other inland communities.
  Dillingham will be somewhere near the western periphery of the
  heaviest snow, so confidence is low on whether they will see 
  the worst conditions with this storm.

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.

&&

$$

AKZ152-111400-
/O.NEW.PAFC.WW.Y.0059.231211T0000Z-231211T1400Z/
Lower Kuskokwim Valley-
Including the cities of Aniak and Sleetmute
359 PM AKST Sat Dec 9 2023

...WINTER WEATHER ADVISORY IN EFFECT FROM 3 PM SUNDAY TO 5 AM
AKST MONDAY FROM SLEETMUTE EAST...

* WHAT...Snow and blowing snow expected. Visibility reduced to one
  half mile at times. Total snow accumulations of 4 to 8 inches. 
  Northerly winds gusting as high as 40 mph.

* WHERE...Lower Kuskokwim Valley, from Sleetmute east.

* WHEN...From 3 PM Sunday to 5 AM AKST Monday.

* IMPACTS...Plan on slippery road conditions. Areas of blowing
  snow could significantly reduce visibility.

* ADDITIONAL DETAILS...Snow and blowing snow will spread north
  from Bristol Bay Sunday evening. The heaviest snowfall amounts
  are currently expected for Lime Village, with lower amounts
  further west. Winds and snow intensity decrease Monday morning,
  ending the threat of half mile visibilities, though light snow 
  will continue through at least Monday evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

&&

$$

http://www.weather.gov/afc

551 
WWAK42 PAFC 110113
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
413 PM AKST Sun Dec 10 2023

AKZ161-111400-
/O.CON.PAFC.BZ.W.0016.000000T0000Z-231211T1400Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
413 PM AKST Sun Dec 10 2023

...BLIZZARD WARNING REMAINS IN EFFECT UNTIL 5 AM AKST MONDAY...

* WHAT...Blizzard conditions and heavy snow. Visibility reduced to
  one quarter mile. Additional snow accumulations of 3 to 9 
  inches, with local amounts up to 12 inches possible. Highest 
  snow amounts over interior Bristol Bay, including Koliganek and 
  New Stuyahok. Northerly winds gusting 35 to 45 mph.

* WHERE...Bristol Bay.

* WHEN...Until 5 AM AKST Monday.

* IMPACTS...Travel will be difficult. Blowing snow and heavy 
  snow will produce white-out conditions at times.

* ADDITIONAL DETAILS...Dillingham is located along the west of the
  heaviest snow, which will lead to snowfall amounts on the lower
  end of the range, with additional accumulations around 3 inches.
  However, blizzard conditions are likely to continue to be
  observed there, despite the lower snowfall rates. Snow spreads 
  north to Iliamna this evening. Snowfall rates and winds will 
  diminish Monday morning, allowing visibility to improve.

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.

&&

$$

AKZ152-111400-
/O.CON.PAFC.WW.Y.0059.000000T0000Z-231211T1400Z/
Lower Kuskokwim Valley-
Including the cities of Aniak and Sleetmute
413 PM AKST Sun Dec 10 2023

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 5 AM AKST
MONDAY FROM SLEETMUTE EAST...

* WHAT...Snow and blowing snow expected. Visibility reduced to one
  half mile at times. Total snow accumulations of 2 to 6 inches.
  Northerly winds gusting as high as 35 mph.

* WHERE...Lower Kuskokwim Valley, from Sleetmute east.

* WHEN...Until 5 AM AKST Monday.

* IMPACTS...Plan on slippery road conditions. Areas of blowing 
  snow could significantly reduce visibility.

* ADDITIONAL DETAILS...Snow and blowing snow will spread north
  from Bristol Bay this evening. The heaviest snowfall amounts are
  currently expected for Lime Village, with lower amounts further
  west. Winds and snow intensity decrease Monday morning, ending
  the threat of half mile visibilities, though light snow
  continues through at least Monday evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

&&

$$

http://www.weather.gov/afc

264 
WWAK42 PAFC 111414
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
514 AM AKST Mon Dec 11 2023

AKZ161-111515-
/O.EXP.PAFC.BZ.W.0016.000000T0000Z-231211T1400Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
514 AM AKST Mon Dec 11 2023

...BLIZZARD WARNING HAS EXPIRED...

Winds continue to steadily decrease across the region this
morning. While periods of snow will likely persist into the 
afternoon and evening hours with the continued presence of an
upper low over the region, the threat for reduced visibility due 
to blowing snow has diminished. Thus, the blizzard warning is 
being allowed to expire.


$$

AKZ152-111515-
/O.EXP.PAFC.WW.Y.0059.000000T0000Z-231211T1400Z/
Lower Kuskokwim Valley-
Including the cities of Aniak and Sleetmute
514 AM AKST Mon Dec 11 2023

...WINTER WEATHER ADVISORY HAS EXPIRED...

Diminishing winds and a decrease in snowfall rates are forecast
through the remainder of the morning hours. While light snow will
continue potentially through this afternoon and evening, 
additional accumulations should be on the lighter side of an inch
or two before snow comes to an end.

$$

http://www.weather.gov/afc

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
530 AM AKST Sat Dec 9 2023

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

Key Messages:

-A system will bring snowfall to the Kenai Peninsula into Anchorage
and the Mat-Su Valley today. Heaviest snowfall will be focused along
the coast, as well as the Seward Highway from Girdwood south to
Seward, where 3 to 6 inches of snow is possible by this afternoon.

-Sunday through early next week: A series of low pressure systems
will bring a nearly continuous stream of moisture into the Kenai and
Chugach Mountains. Several feet of snowfall is likely for the
mountains, including the higher elevation passes on the Seward and
Richardson Highways.

Discussion:

An active winter weather pattern is well underway for southcentral
Alaska. GOES water vapor imagery shows three items of interest: 1) A
deep upper-level low spinning across southwest AK. 2) A shortwave
trough rotating about the aforementioned low that is projected to
lift across the Kenai Peninsula and the rest of southcentral Alaska
later today. 3) A developing low that's currently (as of 430am
Saturday) a couple hundred miles south of the central Aleutians that
is expected to phase with the aforementioned SW AK low and then move
into southcentral Alaska Sunday into early next week.

As of 430am, radar imagery shows snow has already begun to spread
across much of the Kenai Peninsula, with an area of light snow
already entering the Anchorage Bowl and into the Mat-Su Valley as
well. This is all in response to the shortwave trough coming out of
the AK Peninsula and soon moving through the Kenai Peninsula. A
weak surface low is expected to soon develop across the southern
Kenai Peninsula and work its way up along the Gulf Coast before
moving into the Prince William Sound by late afternoon. The
heaviest precipitation today will be focused along the Kenai
Mountains into the western and central Chugach, particularly
closer to the coast as the surface low drives reinforces an
upsloping component. Much of the Seward Highway from Girdwood
south into Seward should receive in the neighborhood of 3 to 6
inches of snowfall, with the Portage- Whittier area receiving
upwards of 12 inches. Areas from the western Kenai Peninsula
northward through Anchorage and the Matanuska Valley should still
pick up about 1 to 3 inches of snowfall as low/mid- level trough
axis rotates northward.

Precipitation will taper off for the Kenai Peninsula and Anchorage-
MatSu Valley this afternoon, but pick up towards Valdez and Cordova
where a couple inches of snowfall will be possible this evening.

Attention on Sunday then turns back to the west as a deepening area
of low pressure over the North Pacific will move up near Kodiak
Island, bringing widespread gale force (>34kt) and areas of storm
force (>48 kt) winds to the Gulf of Alaska and Cook Inlet.
Widespread precipitation will spread from Kodiak Island up into the
Gulf Coast as a warm front lifts north throughout the day, bringing
an atmospheric river into the coastal mountains. Recent model trends
have the low center on a more westward trajectory up the Cook Inlet.
This regime is a bit more favorable for downsloping across portions
of the western Kenai northward through Anchorage and the Mat-Su
Valley. Meanwhile, heavy precipitation characterized by several feet
of snow is likely for the Kenai and Chugach Mountains. For the road
system, the heaviest snow is likely for Thompson Pass and Valdez, as
well as portions of the Seward Highway. An influx of warmer air is
likely to lead to rain/snow mix or rain for some coastal areas such
as Seward and Whittier by Monday.

While details remain uncertain, confidence is high the deep upper-
level trough will drive another 2-3 areas of low pressure into
southcentral Alaska through midweek. A near continuous stream of
moisture will result in near continuous snow (/low-level coastal
rain) for mountainous areas, with blizzard conditions possible in
susceptible areas such as Thompson Pass. A big forecasting challenge
with this series of systems will be the degree of 'inland'
(including western Kenai and Anchorage area) precipitation as times
of cross-barrier flow should subside, allowing precipitation to fill
back in across the area.

-Brown

&&

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

An unsettled weather pattern will continue over the Bering and
Southwest Alaska through the weekend. The culprit being a
persistent upper low with multiple troughs rotating through its
broader cyclonic flow. Large scale synoptic lift associated with
the low over Southwest is maintaining isolated to scattered light
snow showers from the Kuskokwim Delta down into Bristol Bay.
Additional convective snow showers are tracking from the Bering
Sea into the Eastern Aleutians and Alaska Peninsula. Gusty
conditions will promote blowing snow for coastal regions of
Bristol Bay and parts of the Aleutians Saturday morning into
Saturday afternoon. Attention then turns to Sunday with the
expected development of a stronger upper low.

Models continue to merge a shortwave trough lifting into the
AKPEN from the North Pacific on Sunday with the persistent upper
low over Southwest Alaska. This should result in moderate to
perhaps heavy snow for the Greater Bristol Bay area over the
latter half of the weekend into early next week. Increasing winds
inland of the coast will spread a threat for blowing snow and
potential blizzard conditions from Dillingham into New Stuyahok,
Koliganek, and Iliamna. Snow accumulations through Monday morning
could approach 4 to 8 inches depending upon where the stronger
snowbands develop. A winter storm watch for potential blizzard
conditions has been issued,effective Sunday morning through
Monday morning.

&&

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

The weather pattern continues across the region through Friday.
Ridging over the Western Bering and Canadian Provinces brackets
the reorienting longwave trough over Mainland Alaska. A number of
energetic shortwaves continuing their trek along the Western edge
of the trough bring uncertainty to the composite blend of models
over the initial periods. The closed low center in the mid-trough
weakens through the end of the forecast period, as it loops around
the Southcentral coast. With colder air pouring in with the
trough, most precipitation will be snow showers over Western
Alaska and along most of the Alaska Peninsula and Aleutians. Along
with the snow, gusty winds increase to gale force over the
Eastern Bering, Alaska Peninsula and Eastern Aleutians,
diminishing late Thursday. Further West, a well developed
Kamchatka low extends a front over the Western Bering and
Aleutians, with mixed rain and snow as well as gales along the
front through Friday.

Over the Gulf of Alaska, transient lows and fronts from the North
Pacific spool up a widespread multi-day precipitation event from
the Alaska Peninsula to the Canadian Border. Coastal areas begin
with locally heavy rainfall changing to snow further inland as the
area spreads to the Alaska Range through the end of the week.
Gusty winds offshore increase to gale force for Thursday and
Friday, with a gale barrier jet along the North Gulf Coast late
Thursday, diminishing Friday.

Kutz

&&

.AVIATION...

PANC...Somewhat tricky AVN forecast for Anchorage today as an
area of snow has already moved into the Anchorage bowl. MVFR CIGs
may remain through much of the day with on/off light snow through
the morning. Guidance indicates the heaviest potential for snow
today will be in the 21-00z timeframe, which could lead to brief
periods of IFR CIGs and/or VIS. That said, accumulation through
the day should be minimal... with just around an inch expected.
Winds out of the northeast should pick up a bit later with flow
out of the Matanuska Valley.

Conditions are expected to improve by this evening as the trough
lifts out.

-Brown

&&