Wind Chill Advisory 2, NWS Anchorage, AK

107 
WWAK42 PAFC 081248
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
348 AM AKST Wed Jan 8 2020

AKZ155-082100-
/O.CON.PAFC.WC.Y.0002.000000T0000Z-200108T2100Z/
Kuskokwim Delta-
Including the cities of Bethel, Hooper Bay, and Nunivak Island
348 AM AKST Wed Jan 8 2020

...WIND CHILL ADVISORY REMAINS IN EFFECT UNTIL NOON AKST TODAY...

* WHAT...Very cold wind chills. Wind chills as low as 50 below 
  zero.

* WHERE...Kuskokwim Delta.

* WHEN...Until noon AKST today.

* IMPACTS...The dangerously cold wind chills could cause 
  frostbite on exposed skin in as little as 5 minutes.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use caution while traveling outside. Wear appropriate clothing, a
hat, and gloves. 

&&

$$

AKZ161-082100-
/O.CON.PAFC.WC.Y.0002.000000T0000Z-200108T2100Z/
Bristol Bay-
Including the cities of King Salmon, Dillingham, Naknek, 
and Pilot Point
348 AM AKST Wed Jan 8 2020

...WIND CHILL ADVISORY REMAINS IN EFFECT UNTIL NOON AKST TODAY IN
INTERIOR BRISTOL BAY...

* WHAT...Very cold wind chills. Wind chills as low as 50 below 
  zero.

* WHERE...Interior Bristol Bay, including New Stuyahok and 
  Koliganek.

* WHEN...Until noon AKST today.

* IMPACTS...The dangerously cold wind chills could cause frostbite
  on exposed skin in as little as 5 minutes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Use caution while traveling outside. Wear appropriate clothing, a
hat, and gloves. 

&&

$$

http://www.weather.gov/afc

053 
WWAK42 PAFC 082101
WSWALU

URGENT - WINTER WEATHER MESSAGE
National Weather Service Anchorage AK
1201 PM AKST Wed Jan 8 2020

AKZ155-161-082215-
/O.EXP.PAFC.WC.Y.0002.000000T0000Z-200108T2100Z/
Kuskokwim Delta-Bristol Bay-
Including the cities of Bethel, Hooper Bay, Nunivak Island, 
King Salmon, Dillingham, Naknek, and Pilot Point
1201 PM AKST Wed Jan 8 2020

...WIND CHILL ADVISORY HAS EXPIRED...

$$

http://www.weather.gov/afc

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
455 AM AKST Tue Jan 7 2020

.ANALYSIS AND UPPER LEVELS...

A strong arctic low centered over the Tanana Valley continues to
dominate the Southern Mainland weather as deep arctic air remains
entrenched. Temps across all of the Southern Mainland continue to
run well below average as daytime highs are remaining below zero
except along the immediate coast. A weak trough of low pressure
along the North Gulf Coast is supporting some intermittent snow
showers over Cordova, Valdez, and into the Copper Basin, which is
also keeping slightly warmer temperatures in place given weaker
night time radiative cooling. Southwest Alaska is almost
completely clear as weak offshore flow is only strengthening,
which is keeping fog and any low stratus over the Bering.

Over the Bering Sea, the beginnings of a larger pattern shift is
emerging as a large and dynamic Pacific trough has moved an
occluded frontal boundary over the Aleutian Chain, which has
brought temps to near freezing with a mix of rain and snow.
Eventually, this Pacific trough will move a series of fronts and
lows through the Bering Sea, which will gradually erode the arctic
cold air beginning across Southwest Alaska.

&&

.MODEL DISCUSSION...
The numerical weather models are in good agreement with the
general pattern through Wednesday night, but then begin to show
important discrepancies with a warm front strengthening into a
deep low over the Gulf on Thursday and Thursday night. The
challenge revolves around how far north into the arctic air this
front moves before it begins to rapidly deepen, as this will
dictate whether or not Kodiak Island experiences a substantial
amount of snow or just a glancing shot. Right now this forecast
will take a middle ground scenario and favor the NAM over
Southcentral. Over the Bering and Southwest, the GFS was favored
as it better depicts widespread gale force winds and the
progression of fronts toward the Southwest coast.

&&

.AVIATION...
PANC...Fog continues to be a challenge around the terminal and
likely will be in-and-out for the next day. Confidence is low on
when low CIGS and visibility moves through, but when it does it
will likely be LIFR at times. Things may improve tonight as some
mid level clouds may mitigate the development of fog and stratus.

&&
.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 and 2/Today
through Wednesday night)...
Small scale features and resultant winds and/or clouds will limit
temperature drops in some areas over the next couple days, but the
arctic air mass will remain firmly entrenched across Southcentral
Alaska. A couple weak short-waves rounding the south side of a
deep cold upper low over Interior Alaska will bring a few showers
to the Cordova/Valdez area and clouds and a bit of very light snow
to the Copper River Basin today. The upper low will then dive
southward across Southcentral tonight through Wednesday, leading
to a quick surge of cold air advection southward into the Gulf as
well as tightening pressure gradients. Gap winds, which are
already blowing, will strengthen tonight through Wednesday
morning. Some of the strongest winds can be expected for
Seward/Resurrection Bay, Whittier/Passage Canal, the Valdez area,
and the Copper River Delta.

Meanwhile, a weak upper level short-wave and occluded front along
the Aleutians will track to Kodiak Island tonight, gradually being
overtaken by a building ridge upstream. Thus, it will quickly fall
apart as it crosses Kodiak and the Gulf and any snow that falls
will be light and short-lived. The upper ridge will then quickly
move by and a pattern change will ensue, with systems moving up
from the Pacific into the Gulf.

&&

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

Cold conditions continue across Southwest Alaska today as an
Arctic trough remains positioned over the mainland, keeping
temperatures similar to yesterday. Temperatures will then start
to increase throughout the week as a warm front associated with a
North Pacific low begins to lift north and move over the Alaska
Peninsula tonight, bringing the first round of snow showers to
areas south of King Salmon. A second, more organized, front will
begin to move across the Alaska Peninsula Wednesday. Unlike the
first front, this one will move inland across the Kuskokwim Delta
and the Greater Bristol Bay area by Wednesday afternoon, allowing
for the chance for snow to move farther inland. Snow showers will
persist through Thursday when the front begins to weaken. By
Thursday, temperatures across most of the region will warm above
the zero mark, with the exception over the Lower Kuskokwim Valley,
which will continue to see temperatures below zero. Areas along
the Alaska Peninsula could also see temperatures nearing the
freezing mark or just above by the end of the week.

&&

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

An active pattern remains across the Bering and Aleutians
associated with a North Pacific low lifting to just south of
Shemya today. A triple point low that developed overnight
positioned near Adak will continue to weaken this morning along
with a front out ahead of it. By this afternoon, a strong gale
force low approaches the western Aleutians and will spread across
much of the Bering to the Alaska Peninsula, which will bring
widespread precipitation to the region through Wednesday. As the
fronts continue to bring in warm air and southerly flow, chances
for freezing and heaving freezing spray will be pushed away from
the Pribilofs back towards the ice edge along the Southwest coast.

&&

.MARINE (Days 3 through 5: Thursday through Saturday)...
Bering Sea: Models are consistent from yesterday indicating a
very active pattern for the Bering into the weekend. A broad ~960
mb low will approach the far western Aleutians Thursday evening
bringing a large area of generally southerly gales to areas east
of and including the Pribilofs. As the low deepens on Friday night
into Saturday, storm force winds are possible over the western
Bering, north of the Aleutians. If this verifies, waves up to 40
ft would be expected in that area. The low will slightly weaken
Saturday night, however strong westerly gales will likely to
continue.

Gulf of Alaska: A strengthening low will move west to east over
the southern Gulf on Thursday. There is disagreement among the
models regarding its exact track, however a more northerly
solution would lead to widespread easterly gales and higher seas
into Friday morning. A southerly track would likely keep winds
sub-gale. In any case, a ridge will quickly build in behind the
low by evening. Another, weaker low, will move into the Gulf by
Saturday. Winds look to remain below gales in non-channeled areas
at this time.

&&

.LONG TERM FORECAST (Days 3 through 7: Thu through Mon)...
Models continue to indicate a pattern shift later this week,
especially across western Alaska. An upper level low will move
west of Attu Thursday into Friday. The associated surface front
will bring heavy precipitation to the western and central
Aleutians along with the potential for storm force winds in the
western Bering. This low will amplify the North Pacific ridge out
ahead of it, which will lead to temperatures returning to near
freezing in the Bristol Bay area. This will coincide with the
frontal passage Friday evening and bring heavy precipitation to
all of Southwest Alaska. Southwesterly onshore flow will continue
into Sunday, keeping the warmer temperatures and precipitation
chances for the area through the weekend. Flow will switch to
offshore Monday under a ridge, slightly cooling temperatures.

Well below average temperatures will persist across Southcentral
through Thursday. As noted above, the upper low will deepen in the
Bering and therefore a moist southerly flow aloft will develop in
the western Gulf, bringing relatively warmer temperatures to the
region this weekend. Highs across Anchorage could reach the low
20s on Sunday. Given the lingering cold air in place to the north,
gusty winds and colder wind chills will remain likely in terrain
gaps, including Thompson Pass. Lastly, a weakening front will also
bring a chance of snow over the weekend across Southcentral,
though confidence remains low as to its exact timing or intensity.

&&

.AFC WATCHES/WARNINGS/ADVISORIES...
PUBLIC...Flood Warning 121.
MARINE...Gale 121 127 129 170 180 185.
  Heavy Freezing Spray 121 127 128 129 139 141 160 173-180 185.
FIRE WEATHER...NONE.

&&

SYNOPSIS AND MODEL DISCUSSION...Ahsenmacher
SOUTHCENTRAL ALASKA...SEB
SOUTHWEST ALASKA/BERING SEA/ALEUTIANS...AH
MARINE/LONG TERM...AP

SPECIAL WEATHER STATEMENT
National Weather Service ANCHORAGE AK
1256 PM AKST Tue Jan 7 2020

AKZ181-080545-
Alaska Peninsula-
Including the cities of Cold Bay and Sand Point
1256 PM AKST Tue Jan 7 2020

...TRACE ASH POTENTIAL FROM SHISHALDIN VOLCANO...

Shishaldin Volcano, located on Unimak Island, is currently erupting. A
trace of ash was observed at Cold Bay. The low to mid level wind flow
will carry a portion of the ash plume east and potentially drop trace
amounts of ash as far east as Sand Point.