High Wind Watch 23, NWS Anchorage, AK

305 
WWAK72 PAFC 201401
NPWALU

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
501 AM AKST Wed Dec 20 2017

AKZ161-210100-
/O.CON.PAFC.HW.A.0023.171222T0100Z-171223T0100Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
501 AM AKST Wed Dec 20 2017

...HIGH WIND WATCH REMAINS IN EFFECT FROM THURSDAY AFTERNOON
THROUGH FRIDAY AFTERNOON THROUGH FRIDAY AFTERNOON FOR BRISTOL
BAY...

* LOCATION...Bristol Bay

* WIND...Southeast winds 55 to 65 mph with potential gusts 75 to
  85 mph. 

* TIMING...Southeast winds will begin Thursday afternoon along the
  Alaska Peninsula, moving northeastward along the Aleutian Range
  overnight. Winds will then begin affecting the interior portion
  of Bristol Bay by mid-morning Friday, tapering off slightly 
  Friday afternoon. Strong and gusty southeasterly winds will then
  likely persist into Saturday.

* IMPACTS...High winds may move loose debris and unsecured 
  objects, potentially damaging property. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A high wind watch means there is the potential for a hazardous
high wind event. People are encouraged to closely monitor this
weather situation. Preparation for this potentially dangerous
weather event should begin now.

&&

$$

591 
WWAK72 PAFC 210007
NPWALU

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
307 PM AKST Wed Dec 20 2017

AKZ161-211500-
/O.CON.PAFC.HW.A.0023.171222T0100Z-171223T0100Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
307 PM AKST Wed Dec 20 2017

...HIGH WIND WATCH REMAINS IN EFFECT FROM THURSDAY AFTERNOON
THROUGH FRIDAY AFTERNOON FOR BRISTOL BAY...

* LOCATION...Bristol Bay

* WIND...Southeast winds 55 to 65 mph with potential gusts 75 to 
  85 mph. 

* TIMING...Southeast winds will begin Thursday afternoon along 
  the Alaska Peninsula, moving northeastward along the Aleutian 
  Range overnight. Winds will then begin affecting the interior 
  portion of Bristol Bay by mid-morning Friday, tapering off 
  slightly Friday afternoon. Strong and gusty southeasterly 
  winds will then likely persist into Saturday. 

* IMPACTS...High winds may move loose debris and unsecured 
  objects, potentially damaging property. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A high wind watch means there is the potential for a hazardous
high wind event. People are encouraged to closely monitor this
weather situation. Preparation for this potentially dangerous
weather event should begin now.

&&

$$

286 
WWAK72 PAFC 211321
NPWALU

URGENT - WEATHER MESSAGE
National Weather Service Anchorage AK
421 AM AKST Thu Dec 21 2017

AKZ161-220230-
/O.UPG.PAFC.HW.A.0023.171222T0100Z-171223T0100Z/
/O.NEW.PAFC.HW.W.0025.171222T0100Z-171223T0300Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
421 AM AKST Thu Dec 21 2017

...HIGH WIND WARNING IN EFFECT FROM 4 PM THIS AFTERNOON TO 6 PM
AKST FRIDAY FROM NAKNEK SOUTH AND EAST....

The National Weather Service in Anchorage has issued a High Wind
Warning, which is in effect from 4 PM this afternoon to 6 PM AKST
Friday. The High Wind Watch is no longer in effect. 

* LOCATION...From Naknek south and east.

* WIND...Southeast winds 55 to 65 mph with gusts 75 mph. 

* TIMING...Strong southeasterly winds will begin this afternoon 
  along the Alaska Peninsula, then spread northeastward along the 
  Aleutian Range over the course of this evening. This will bring 
  the strongest winds into the King Salmon and Iliamna areas 
  during the evening and overnight hours. High winds will then 
  persist during the day Friday before weakening below warning 
  criteria during the evening.

* IMPACTS...High winds may move loose debris and unsecured 
  objects, potentially damaging property. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A high wind warning means a hazardous high wind event is expected
or occurring. People are urged to secure loose objects that could
be blown around or damaged by the wind.

&&

$$

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
541 AM AKST Tue Dec 19 2017

.ANALYSIS AND UPPER LEVELS...
Looking at water vapor satellite this morning, it's pretty clear
what the main focus for the coming days will be. A beauty of a low
pressure system is occluded in the northwest Bering Sea. The front
associated with it stretches from the Chukchi Sea southward
through western Alaska and down into the sub-tropics. The sub-
tropical connection is bringing precipitable water values around
.7 inches, good for 200% of normal for this time of year. Behind
the front, open-celled cumulus show up water vapor, showing
instability extends quite high in the atmospheric column and
indicative of strong cold advection.

The front itself brought gale-force winds to the southwest
mainland overnight and a slow transition from snow to rain in most
places. For Southcentral Alaska, the front is beginning to push
into our area this morning.

&&

.MODEL DISCUSSION...
The general synoptics are well agreed upon among the models as far
as frontal progression and timing. The differences come with small
details such as amount of Turnagain Arm wind and downslope drying,
and low-level temperatures, all making for a very challenging
forecast around the Cook Inlet region.

&&

.AVIATION...
PANC...Uncertainty today revolves around precipitation type.
Confidence is higher that the airport will see Turnagain Arm wind.
The question is how high do surface temperatures spike when the
winds come in? The depth of warm air should be fairly shallow, so
mixed precipitation is expected at this time. Once winds begin to
change from southeast to southwest in the afternoon, precipitation
intensity could change rain back to snow as the cold air is
arriving behind the front.

&&

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2)...

There is warmer air moving into Southcentral Alaska with the
southwest flow aloft and fairly deep moisture with the front
approaching from the west.
The most challenging portion of the forecast is in the northern
Cook Inlet region including the Anchorage and Matanuska Valley
areas today with precipitation type being the most difficult part.
The issue all resolves around the Turnagain Arm and Knik River
wind. With gusty southeast winds expected across the Anchorage
area and Matanuska Valley, it will likely delay the precipitation
in the morning which is why there is just a chance of snow. These
Southeast winds typically either downslope out these areas with
little to no precipitation, or enough warm air spills into the
area to cause rain or freezing rain and it is possible for there
to be a little freezing rain this morning. There is a good chance
that this afternoon will see some precipitation with a rain and
snow mix. Late this afternoon into early evening the southeast
winds will shift to the south- southwest and this is when there
will likely be a burst of snow that could give and inch or two
accumulation. The timing of this will probably be around the
afternoon rush hour commute. The southerly winds will also be a
little gusty (though not as strong as the southeast winds during
most of the day) which could reduce visibilities at times during
the late afternoon to early evening.

The Susitna Valley remains under a Winter Storm Warning due to
snow with 6 to 12 inches expected across most of the valley.
Higher amounts closer to 16 inches may occur north of Talkeetna as
one gets into the passes of the Alaska Range.

&&

.SHORT TERM FORECAST SOUTHWEST ALASKA (Days 1 through 3)...
Conditions should begin to improve with diminishing winds and
precipitation from west to east this morning as the front
continues to dissipate. Cold air advection riding along the back
edge of the front should allow for rain to transition to snow for
a few hours in most areas before ending, leaving generally light
accumulations of around an inch or so. This will be the beginning
of a broad area of cold air advection that will move through the
region into mid week as the Bering low continues to lift towards
the Bering Strait. The low position will remain well north and
west of the area however, so any snow showers that do pass through
shouldn't be more than isolated-scattered in coverage with
minimal accumulations expected. Starting Thursday, a North Pacific
low approaching from the south will bring a return to above
freezing temperatures to much of the region for the end of the
work week, along with strong easterly winds along the
Aleutian/Alaskan Ranges. These strong easterly winds will
limit most if not all of the precipitation in the downslope prone
areas of Eastern Bristol Bay, while Western Bristol Bay and the
Kuskokwim Delta should expect to see rain/snow with gusty easterly
winds into Friday.

&&

.SHORT TERM FORECAST BERING SEA/ALEUTIANS (Days 1 through 3)...
A very active weather pattern continues over the region as the
departing gale force low over the Northern Bering will quickly be
replaced by a solid storm force low by this evening. For today,
the departing Northern Bering low will bring a broad area of
westerly gales and snow showers to most of the Bering Sea, along
with a the possibility of a few lightning strikes over the
Southern Bering. Attention then quickly shifts to the incoming
low to the Western Aleutians which will bring a broad area of
southerly storm force winds stretching from the Central Aleutians
northward into the Pribilof Islands for Wednesday. This front also
has the potential to produce near warning level (75 mph) gusts to
the Adak area late tonight-early Wednesday, however at this point
conditions are not expected be long lived or widespread enough
for a warning. Strong warm air advection will accompany this front
however, which should cause all precipitation to fall as rain as
well as keep the much stronger winds aloft from mixing down to the
surface. Yet another storm force North Pacific low will then take
a much more northerly track towards the AKpen on Thursday,
focusing the most active weather to east of the Pribilofs into
Friday.

&&

.LONG TERM FORECAST (Wednesday through Saturday)...

By Wednesday, the mainland will be experiencing a brief break in
the weather as the North Pacific Ridge builds in, while yet
another storm force low moves into the Bering Sea. Temperatures
over the mainland will cool off, as colder air moves in aloft and
clearing will allow the air mass to cool overnight. Meanwhile, in
the Bering, the storm force low will bring another slug of warm
air aloft and precipitation will be mixed.

After this quick break, the ridge will settle in, forcing the jet
stream southward. The next low pressure systems we see will
approach the state from the south beginning Thursday afternoon,
which will provide a connection to some very moist air from
further south. Models continue to bring two lows across the
Alaska Peninsula, focusing the brunt of the weather first on
Kodiak, then on the southern Kenai Peninsula. There has been some
variation in the model runs on whether the heaviest precipitation
will fall in Kodiak, or later on the coastal Kenai, or even as far
east as Yakutat. Right now the thinking focuses the heaviest rain
on Kodiak for next weekend, but we'll continue to watch these
systems carefully, keeping concerns for holiday travelers in mind.
&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Winter Storm Warning 145.
MARINE...Storm 175 176 177 178 179 181 185.
         Gale 165 170 174 180.

&&

SYNOPSIS AND MODEL DISCUSSION...MTL
SOUTHCENTRAL ALASKA...EZ
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...DEK
LONG TERM...LF