High Wind Watch 9, NWS Anchorage, AK

148 
WWAK71 PAFC 241339
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
439 AM AKST Tue Nov 24 2020

AKZ125-250200-
/O.EXA.PAFC.HW.A.0009.201125T1500Z-201126T0100Z/
Western Prince William Sound-
Including the cities of Whittier, Seward, Girdwood, 
and Moose Pass
439 AM AKST Tue Nov 24 2020

...HIGH WIND WATCH IN EFFECT FROM WEDNESDAY MORNING THROUGH
WEDNESDAY AFTERNOON ALONG THE TURNAGAIN ARM AND PORTAGE VALLEY...

* WHAT...East winds 40 to 60 mph with gusts up to 80 mph 
  possible.

* WHERE...TURNAGAIN ARM AND PORTAGE VALLEY

* WHEN...From Wednesday morning through Wednesday afternoon.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A high wind watch means there is potential for a hazardous high
wind event. Monitor the latest forecasts and warnings for updates
on this situation. Fasten loose objects or shelter objects in a
safe location prior to the onset of winds.

&&

$$

AKZ101-250200-
/O.CON.PAFC.HW.A.0009.201125T1500Z-201126T0100Z/
Anchorage-
Including the cities of Anchorage, Eagle River, Indian, 
and Eklutna
439 AM AKST Tue Nov 24 2020

...HIGH WIND WATCH REMAINS IN EFFECT FROM WEDNESDAY MORNING
THROUGH WEDNESDAY AFTERNOON ALONG TURNAGAIN ARM AND HIGHER 
ELEVATIONS...

* WHAT...East winds 40 to 60 mph with gusts up to 80 mph 
  possible.

* WHERE...Turnagain Arm and higher elevations of Anchorage.

* WHEN...From Wednesday morning through Wednesday afternoon.

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

* ADDITIONAL DETAILS...The strongest winds are expected along 
  the typical areas of west Turnagain Arm, upper Potter Valley, 
  and the upper Hillside of Anchorage. However, there is some 
  potential for winds gusting as high as 60 mph to come down the 
  Anchorage hillside. Stay tuned as we continue to evaluate this 
  storm.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A high wind watch means there is potential for a hazardous high
wind event. Monitor the latest forecasts and warnings for updates
on this situation. Fasten loose objects or shelter objects in a
safe location prior to the onset of winds.

&&

$$

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

315 
WWAK71 PAFC 250020
NPWAER

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
320 PM AKST Tue Nov 24 2020

AKZ125-250130-
/O.CAN.PAFC.HW.A.0009.201125T1500Z-201126T0100Z/
Western Prince William Sound-
Including the cities of Whittier, Seward, Girdwood, 
and Moose Pass
320 PM AKST Tue Nov 24 2020

...HIGH WIND WATCH IS CANCELLED THROUGH WEDNESDAY AFTERNOON
THROUGH PORTAGE VALLEY AND EASTERN TURNAGAIN ARM...

East winds gusting to 55 to 70 mph are expected on Wednesday
through Portage Valley and Eastern Turnagain Arm. Since this is
below warning thresholds, the high wind watch has been cancelled.

$$

AKZ101-251430-
/O.UPG.PAFC.HW.A.0009.201125T1500Z-201126T0100Z/
/O.NEW.PAFC.HW.W.0017.201125T1500Z-201126T0100Z/
Anchorage-
Including the cities of Anchorage, Eagle River, Indian, 
and Eklutna
320 PM AKST Tue Nov 24 2020

...HIGH WIND WARNING IN EFFECT FROM 6 AM TO 4 PM AKST WEDNESDAY
ALONG TURNAGAIN ARM AND HIGHER ELEVATIONS...

* WHAT...East winds 40 to 60 mph with gusts up to 80 mph 
  expected.

* WHERE...Turnagain Arm and higher elevations of Anchorage,
  including the upper Hillside.

* WHEN...From 6 AM to 4 PM AKST Wednesday.

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

* ADDITIONAL DETAILS...The strongest winds are expected late
  morning through early afternoon. The lower Hillside as well as
  lower elevations near the mountains can expect peak winds gusts
  of 40 to 50 mph Wednesday afternoon, while the remainder of
  Anchorage can expect gusts of 20 to 35 mph. Winds at lower
  elevations will be generally short-lived compared with the
  warning area.

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
http://weather.gov/afc

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
547 AM AKST Mon Nov 23 2020

.ANALYSIS AND UPPER LEVELS...

A strengthening area of low pressure is moving northeastward along
the AKPEN along a negatively-tilted trough that extends from the
central Bering Sea to the western Gulf of Alaska. This low is
undergoing rapid intensification as it is located in the left-exit
region of the jetstream with the core of the jet being located
near the center of cyclonic vorticity (center of counterclockwise
rotation). Furthermore, the wrap around occlusion is also helping
to enhance the cyclonic vorticity to further deepen this low. A
second low is currently moving into the western Bering Sea and is
strengthening due to the center of cyclonic vorticity associated
with this low being located near the core of the jet. The
jetstream has become more amplfied compared to 24hrs ago with
ridges over the AlCan Border and the central Aleutians and a
trough over Southwest Alaska and the AKPEN where the
aforementioned rapidly developing low is.

Closer to the surface, radar imagery shows snow along the southern
Kenai Peninsula. Radar also shows snow along Bristol Bay and into
the eastern Kuskokwim Delta. Temperatures are warmer for much of
the AKPEN and across Prince William Sound, making for rain being
the precipitation type in those locations. Rain is also observed
across Kodiak Island where temperatures are in the upper 30sF to
low 40sF. Observations show winds gusting to hurricane force
(64kts) at King Cove. Scatterometry (ASCAT) data shows sustained
winds nearing hurricane force south of the center of the low.
ASCAT data also shows winds along the frontal boundary nearing
storm force in the western Aleutians.

&&

.MODEL DISCUSSION...

Guidance is in good agreement with the position and intensity of
synoptic scale features at both the surface and in the upper
levels. With respect to the model output wind forecast associated
with the front that will move across the Bering, the more
aggressive end of guidance has widespread storm force while the
more conservative end has gale force winds. Guidance is consistent
with strengthening the low center to near 960 mb. Due to the
strength of the low combined with the current ASCAT pass, the
aggressive end of guidance is favored as winds are already near
storm force along the frontal boundary. Even the aggressive end of
guidance may be a bit underdone as a small area of hurricane force
winds cannot be ruled out, especially in locations that are prone
to localized funneling from the south.

&&

.AVIATION...
PANC...VFR conditions will be the predominant conditions through
this TAF period. Temporary MVFR conditions are likely through 16z
as light snow showers may reduce visibility to 4SM, though
ceilings will remain around 4000ft AGL inside of these areas of
light snow. Winds will increase out of the north at 19z to 15kts
gusting to 20kts. These winds will ease after 00z.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2...Monday
and Tuesday)...
The rapidly deepening surface low over the Gulf of AK is right on
track and meeting expectations. Hurricane-force winds have been
observed over some of the marine zones. The low is nearing its
minimum central pressure (~954mb) and should start to weaken
later this morning. It will continue to bring plenty of storm-
force sustained winds across the waters today as it pushes a front
up against the north Gulf coast. This system is also packing a
healthy amount of precipitation and will continue to push it into
Western Prince William Sound and up the Portage Valley. There
could even be enough moisture to push some snow showers into the
typical downsloped locations such as Anchorage and Kenai this
morning. Just about all locations are now solidly in snow (vs
rain) with this event due to its very southern track. The lone
hold out continues to be Whittier where just enough warm air off
Passage Canal continues to cause precipitation to be a mix of
rain and snow. Expect periods of blowing snow to continue for
parts of Kachemak Bay, Turnagain Pass, and Thompson Pass through
the day. As the system wraps up very tightly later this afternoon,
it will bring an abrupt end to the precipitation from west to
east.

There will be brief respite in the active weather on Tue. A
transient ridge of high pressure will slide across the area
bringing dry conditions with significantly calmer winds for most
locations. The exception to this will be some of the gaps along
the coast such as Seward and Whittier where some gusts will
persist. By early Wed, the next system will rapidly approach the
Western Gulf. This system has many of the same features as the one
that passed through Friday-Saturday. It will feature a triple
point low near Kodiak Island with another round of strong winds.
The track of this storm will be farther north, so precipitation
type could be a challenge once again.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 and 2...This morning
through early Wednesday morning)...

A sub-960 mb low pressure currently just southeast of Kodiak
Island continues moving into the Gulf of Alaska this morning. On
the northwest side of the system, light snow was occurring from
Bristol Bay all the way west into the Yukon-Kuskokwim Delta. This
light snow will continue to bring reduced visibilities through
around mid-morning before tapering to snow showers and then ending
by late morning from northwest to southeast. Any additional
accumulation in Bethel this morning is expected to be light and
under an inch for a storm total with an additional 1-3 inches for
Bristol Bay with storm total snow accumulations of 4-8 inches.
North winds 15-25 mph with gusts of 30-40 mph will continue to
accompany the snow this morning before diminishing late morning
into the early afternoon hours.

A brief lull in the action is expected for this afternoon into
this evening before the next system moves into the region. A
frontal system is expected to begin moving onshore the YK-Delta
this evening with snow to start before quickly changing over to
rain especially for coastal regions as much warmer air is brought
in. Bristol Bay and the Middle Kuskokwim Valley may get some
precipitation out of the initial band of precipitation tonight
into Tuesday morning but the main action doesn't arrive until
Tuesday evening and continues through Wednesday morning. Interior
areas are expected to hold onto the cold air longer with the
better chance of snow with light accumulations possible at this
time across the Middle Kuskokwim Valley. Unlike this last event,
this system will be too warm for the coastal regions to see
accumulating snow with rain likely for Dillingham this time around
as temperatures warm up into the 30s. While it still doesn't
appear likely, there is the risk for interior locations to
possibly have a period of freezing rain if cold air remains
stubborn at the surface for areas such as Bethel east and interior
Bristol Bay such as Koliganek. This was left out of the forecast
package again this morning as there was not enough confidence to
place this in it.

&&

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

A sub-960 mb low pressure system currently located southeast of
Kodiak Island continues moving into the Gulf of Alaska this
morning. On the northwest and west side of the system, rapid
pressure rises, tight pressure gradient, and cold air advection
are providing for very windy conditions on the back side of the
low. As a result, Hurricane Force Wind Warnings remain active for
the marine zones south of the AKPEN this morning. Wave heights of
30-40 ft are also expected with the highest seas in the
southernmost portions of the marine zones. Also, King Cove was
seeing wind gusts upwards of 65-73 kts (80 mph) much of the
overnight which prompted a High Wind Warning to be issued for the
southern AKPEN including Cold Bay and Sand Point until noontime
today.

Another storm system is currently centered to the northwest of
Attu Island with its associated storm force front moving across
the western Aleutian Chain this morning. This front will continue
moving eastward across the Bering today reaching the eastern
Bering and Bristol Bay by Tuesday night before moving onshore.
Wave heights on the Bering side are expected to be 20-28 ft with
22-32 foot seas on the Pacific side. Periods of rain are also
expected as the front moves through. After the front passes
through, cold air advection will take over and widespread snow
showers are possible beginning tonight across the western Bering
and continuing eastward encompassing much of the Bering by early
Wednesday morning.

&&

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

Gulf of Alaska:

Good confidence with overall pattern but some uncertainty remains
in the details during the 3-5 day timeframe. A front enters the
Gulf Wednesday with Gales and locally storms southeast of
Cordova. A low forms along this front Wednesday near the Shelikof
Strait and moves either up Cook Inlet or towards Prince William
Sound but low confidence on the track of this low. This front
moves inland Wednesday night. Thursday afternoon a Gale force low
enters Gulf with a chance of a small area of storm force winds
south of the low, however low confidence on track and strength.
The low will weaken and move into eastern Gulf Friday morning.
Friday afternoon a gale force front moves into the southwestern
Gulf with more uncertainty on timing of this front

Bering Sea:

Fair confidence as a weak front with small crafts moves across the
Bering Wednesday and moves into Southwest Alaska by Thursday
morning. Another low enters the western Aleutians late Thursday
with high end Storms mainly across the Pacific side of Aleutians.
This low will move along the Aleutians/south Bering on Friday.
There is a low chance of Hurricane force winds, but lower
confidence with strength and track of this low.

&&

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

Progressive flow will dominate the long term with a series of
fronts and lows moving across the Aleutians and Bering into
Southwest and Southcentral Alaska. These systems may bring chances
of accumulating snow. Fair to Good confidence for Thursday and
Friday but lower confidence Saturday and Sunday as models are all
over the place with timing and track of systems. A weak front
will move across the Bering on Thursday with rain and snow showers
from the Pribilofs into the Aleutians. This front moves into
southwest Alaska Thursday morning as it dissipates with areas of
light rain and snow, but no impacts. Across Southcentral a
weakening front moves inland on Thursday with light accumulating
snowfall. Another low is expected to move across the Gulf late
Thursday into Friday with light rain and snow, but minimal
impacts. A strong low will move across the southern Bering near
the Aleutians late Thursday into Friday with an accompanying front
moving south of the Aleutians. This will produce storm force
winds and possibly even Hurricane force winds mainly on the
Pacific side of the Aleutians. Friday into Saturday southwest
Alaska may receive some accumulating snow on north side of this
low. This low and frontal system will track into the Gulf late
Friday and Saturday with at least Gale force winds along front,
there is a chance of heavier rain and snow from Kodiak Island
towards the Kenai and Prince William Sound. However, a lot of
uncertainty Saturday with the evolution of this system progressing
across the Gulf. Sunday models are all over the place with
placement of lows and fronts, but there is good confidence that
the active pattern will continue

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Weather Advisory 125 161.
High Wind Warning 181.
MARINE...Hurricane Force Wind Warning 131 150 155.
Storm Warning 119 120 130 132 138 139 160 165 170 171 172 173 174 175 176
177 178 179 181 351 352 412 413 414.
Gale Warning 125 127 136 140 180 185 411.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...ED
SOUTHCENTRAL ALASKA...MO
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...MV
MARINE/LONG TERM...RC