High Wind Warning 12, NWS Anchorage, AK

689 
WWAK71 PAFC 290043
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
343 PM AKST Mon Nov 28 2022

AKZ131-291400-
/O.CON.PAFC.HW.W.0012.221129T0600Z-221130T0600Z/
Northeast Prince William Sound-
Including the cities of Valdez and Thompson Pass
343 PM AKST Mon Nov 28 2022

...HIGH WIND WARNING REMAINS IN EFFECT FROM 9 PM THIS EVENING TO
9 PM AKST TUESDAY...

* WHAT...Northeast winds 40 to 50 mph with gusts up to 75 mph 
  expected.

* WHERE...Valdez and Thompson Pass.

* WHEN...From 9 PM this evening to 9 PM AKST Tuesday.

* IMPACTS...High winds may move loose debris, damage property, 
  and cause power outages. Travel will be difficult, especially 
  for high profile vehicles.

* ADDITIONAL DETAILS...Cold air, an upper-level shortwave, and 
  strong winds in the upper atmosphere will combine and allow 
  for high winds to develop this evening and gradually decrease 
  Tuesday evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People are urged to secure loose objects that could be blown
around or damaged by the wind. Prepare for the possibility of
widespread power outages. Use caution if you must drive.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/afc

665 
WWAK71 PAFC 291251
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
351 AM AKST Tue Nov 29 2022

AKZ131-300200-
/O.CON.PAFC.HW.W.0012.000000T0000Z-221130T0600Z/
Northeast Prince William Sound-
Including the cities of Valdez and Thompson Pass
351 AM AKST Tue Nov 29 2022

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 9 PM AKST THIS
EVENING...

* WHAT...Northeast winds 40 to 50 mph with gusts up to 75 mph 
  expected.

* WHERE...Valdez and Thompson Pass.

* WHEN...Until 9 PM AKST this evening.

* IMPACTS...High winds may move loose debris, damage property, 
  and cause power outages. Travel will be difficult, especially 
  for high profile vehicles.

* ADDITIONAL DETAILS...Cold air, an upper-level shortwave, and 
  strong winds in the upper atmosphere will combine and allow 
  for high winds to develop this evening and gradually decrease 
  Tuesday evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People are urged to secure loose objects that could be blown
around or damaged by the wind. Prepare for the possibility of
widespread power outages. Use caution if you must drive.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/afc

841 
WWAK71 PAFC 300029
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
329 PM AKST Tue Nov 29 2022

AKZ131-300600-
/O.CON.PAFC.HW.W.0012.000000T0000Z-221130T0600Z/
Northeast Prince William Sound-
Including the cities of Valdez and Thompson Pass
329 PM AKST Tue Nov 29 2022

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 9 PM AKST THIS
EVENING...

* WHAT...Northeast winds 40 to 50 mph with gusts up to 75 mph 
  expected.

* WHERE...Valdez and Thompson Pass.

* WHEN...Until 9 PM AKST this evening.

* IMPACTS...High winds may move loose debris, damage property, 
  and cause power outages. Travel will be difficult, especially 
  for high profile vehicles.

* ADDITIONAL DETAILS...Cold air, an upper-level shortwave, and 
  strong winds in the upper atmosphere will combine and allow 
  for high winds to develop this evening and gradually decrease 
  Tuesday evening.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

People are urged to secure loose objects that could be blown
around or damaged by the wind. Prepare for the possibility of
widespread power outages. Use caution if you must drive.

&&

$$

For more information from the National Weather Service visit
https://weather.gov/afc

454 
WWAK71 PAFC 300554
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
854 PM AKST Tue Nov 29 2022

AKZ131-300700-
/O.EXP.PAFC.HW.W.0012.000000T0000Z-221130T0600Z/
Northeast Prince William Sound-
Including the cities of Valdez and Thompson Pass
854 PM AKST Tue Nov 29 2022

...HIGH WIND WARNING WILL EXPIRE AT 9 PM AKST THIS EVENING...

Winds are diminishing and will continue to do so into Wednesday
morning. 

$$

For more information from the National Weather Service visit
https://weather.gov/afc

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
422 PM AKST Sun Nov 27 2022

.ANALYSIS AND UPPER LEVELS...
The cold upper level trough is over the AlCan border this
afternoon with an upper level ridge building over southern
mainland Alaska and another upper level low in the northwest
Bering Sea. The jet stream can be seen on satellite running
northward from around 25N 170W to over the Pribilof Islands and
curving toward Southwest Alaska. This is advecting a bit of warm,
moist air into the Bering Sea as can be seen on the nearly 50F
temperature readings at Dutch Harbor and Adak. However, the cold
air remains over southern Alaska, including the Kuskokwim Delta
and Bristol Bay regions as they are on the north side of a front
that stretches from south of Kodiak through the Alaska Peninsula
and northwest to the low center in the northwest Bering Sea. The
strength of this boundary can be seen in this afternoon's 1 PM
AKST temperatures where Cold Bay was sitting at 42F while Port
Heiden was still only 22F. This set up is the reason for the snow
for Southwest Alaska and Kodiak Island tonight.

Cold air in the Northern Cook Inlet region and Copper River
Basin, combined with a low in the northeast Gulf of Alaska is
bringing gusty gap winds along the north Gulf coast. Strongest
winds are in the Valdez area and Valdez will likely continue to
see the strongest winds over the next few days.

&&

.MODEL DISCUSSION...
Models are in good synoptic agreement until late in the week.
However there are some smaller differences that will make some
significant difference in the forecast over the next few days. The
first of these is with the way the front will cross the Kodiak
region tonight into Monday. The NAM is a little farther north than
other models and would bring some snow as far north as Homer.
This solution also brings in warmer air over Kodiak and
potentially turn precipitation to a rain/snow mix over the city
of Kodiak. However, the GFS, GEM, and EC all have a slightly
farther south track keeping the snow south of Homer and the main
area of lift over Kodiak Island resulting in heavier snow in
Kodiak which remains the preferred solution. Subtle differences in
the pressure gradient and upper level features will also impact
the strength of the Valdez winds so that is feeding into the
uncertainty there.

&&

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

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3:
Tonight through Wednesday night)...

Cold and clear conditions persist across Southcentral as an
upper-level ridge builds over the region. Northerly cold air
advection maintains gusty outflow winds along the north Gulf
coast, with especially gusty winds located through Thompson Pass
and the Valdez area. A High Wind Watch for both Thompson Pass and
Valdez is in effect from Monday evening through late Tuesday
night for northeast winds 40 to 50 mph with gusts up to 75 mph
possible. Cold air, upper-level forcing, and strong winds in the
upper atmosphere are expected to combine to promote the
development of these high winds. In general, gusty offshore flow
is expected to persist along the Southcentral coast through
Tuesday. A northeasterly Matanuska Valley wind is also expected to
develop tonight and strengthen through Tuesday.

Precipitation will return to Kodiak Island from tonight through
Tuesday morning as a low tracks from the eastern Bering into the
western Gulf. The attendant front will spread snow from west to
east across the island starting this evening, with the heaviest
snowfall expected to occur on Monday morning over the center of
the island. Total snow accumulations of 4 to 8 inches are
expected (up to 10 inches in the mountains), and a Winter Weather
Advisory for snow amounts remains in effect from 11pm this evening
to 3pm AKST Monday. Kodiak City is expected to get up to 6 inches
of snow, while the eastern coast of the island will see lower
amounts around 1 to 2 inches. Akhiok will likely begin as snow
before transitioning to rain early on Monday morning. As the low
dives into the southeastern Gulf, precipitation across Kodiak
Island tapers off by Monday afternoon. A large Bering ridge
builds east across Southcentral for the remainder of the short
term forecast period. As a result, expect more clear, dry, and
cold conditions across the region.

&&
.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...

The longwave pattern features a high amplitude ridge over the
Eastern Bering. There is a jet core of 150 knots near Dutch
Harbor. On satellite imagery (GOES Airmass RGB) there is a mature
low with the occlusion bent back into the Northern Bering and the
warm front pushing into the Southwest AK. Also on satellite
imagery (CIMSS Mimic PW) there is a deep fetch of moisture from
Cold Bay to the Central Pacific. The models continue to bring this
moisture to Southwest Alaska this forecast period. The leading
edge of the precipitation shield into Nunivak and coastal regions
this afternoon. Nunivak Island can anticipate reduced visibilities
down to a half-mile at times due to blowing snow. Areas along the
Kuskokwim Delta coast could see up to two inches of snow
accumulation plus the blowing snow. A Winter weather advisory was
also issued for Nunivak Island and the Kuskokwim Delta Coast
(also known as Public Zone 155). The heaviest amounts of snow are
expected from Togiak to King Salmon (over night Sunday and into
Monday afternoon) where 4 to 10 inches of snow is expected. A
Winter Weather Advisory has been issued for the Bristol Bay Area
(also known as Public Zone 161). Tuesday and most of Wednesday
look dry and cold.

&&

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

The longwave pattern features a high amplitude ridge over the
Eastern Bering. There is a jet core of 150 knots near Dutch
Harbor. On satellite imagery (GOES Airmass RGB) there is a mature
low with the occlusion bent back into the Northern Bering and the
warm front pushing into the Southwest AK. Also on satellite
imagery (CIMSS Mimic PW) there is a deep fetch of moisture from
Cold Bay to the Central Pacific. The models bring this moisture to
the Aleutian chain and into the Bering this forecast period. The
Pribilof Islands will see mostly a rain/snow mix, while the
Aleutian chain will mostly see rain. Its pretty impressive how far
north the models bring the thermal ridge on the 1000-850 mb
"thickness" over the Central Bering. By Monday morning there is a
974 mb low northwest of Attu Island and the front will clip Attu
and Shemya. Tuesday, there will be a 980 mb west of Kamchatka.

&&

.LONG TERM FORECAST (Days 4 through 7: Wednesday through
Saturday)...

The long term begins with a high amplitude ridge over far western
Alaska, shortwave troughs over Southeast Alaska and far eastern
Russia and a closed upper low over the North Pacific. Expecting
fairly bimodal weather across the east and west, with the
Southcentral expected to remain dry and cold and Southwest
expected to be warm and wet. The first notable weather feature is
a shortwave driving over the ridge and into Western Alaska. There
is still considerable uncertainty on the north/south position of
the shortwave, but with ample warm air aloft and lingering cold
air at the surface, freezing rain is possible to likely for the
Kuskokwim Delta and Lower Kuskokwim Valley. This will likely
transition to rain towards the end of the system when onshore
flow takes over, but rain on snow can create it's own hazards and
develop ice.

After the system impacts the west on Wednesday it's expected to
drive quickly over Southcentral and into the Gulf Wednesday night
into Thursday. This may reinvigorate outflow winds through gaps
and passes of Southcentral. A shortwave ridge will then
reestablish itself over western Alaska briefly before another
system drives through the area Friday. This will bring yet again
more rain and freezing rain Friday into Saturday for Southwest,
but cold air advection on the backside of the system should finish
the storm off as snow. How this system moves into Southcentral
remains highly uncertain, but with considerable cold air advection
moving in behind the low, the pattern change should begin over
the weekend as the ridge breaks down.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory: 155, 161, 171.
         High Wind Watch: 131.

MARINE....Storm Warning: 411, 412.
          Gale Warning: 127, 178, 180-181, 185, 414.
          Heavy Freezing Spray: 180

FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...EZ
SOUTHCENTRAL ALASKA...AF
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...PS
LONG TERM...CJ