Area Forecast Discussion
Issued by NWS Anchorage, AK

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000
FXAK68 PAFC 030104
AFDAFC

Southcentral and Southwest Alaska Forecast Discussion
National Weather Service Anchorage AK
404 PM AKST Sat Mar 2 2024

.SHORT TERM FORECAST SOUTHCENTRAL ALASKA (Days 1 through 3/Today
through Monday night)...

Relief from the stronger winds across Southcentral is on its way
this evening in the form of temporary high pressure ridging in
from the west. A shortwave trough offshore of the Alaska Panhandle
continues to move off to the southeast. The movement of the
trough is helping to break down high pressure along the ALCAN
border while allowing a new amplified ridge of high pressure over
western Alaska to move into Southcentral. The end result will see
a strong pressure gradient over Southcentral, responsible for days
of enhanced northerly winds, finally come to an end.

Short term concerns then transition to cooler temperatures
anticipated tonight into Sunday morning. Calm winds should allow
warmer temperatures to radiate away more efficiently with surface
temperatures dropping through the morning hours tomorrow. The one
caveat entails the possibility of areas of fog developing
tonight, which would deter stronger radiational cooling. This
seems unlikely, however, as days of persistent northerly flow has
dried out the atmosphere sufficiently. The 00z sounding out of
Anchorage shows a dry atmospheric profile from the ground up, with
low-level RH values hovering around 20%, decreasing to below 10%
at the mid-levels. Thus, confidence is higher in temperatures
bottoming out tonight. The Copper River Basin will be coldest with
overnight lows dropping down to -20 degrees to as low as -30
degrees along the Edgerton and Richardson Highways. Across the
Anchorage Bowl temperatures will be warmer but with a larger
spread. The west side of Anchorage may stay just above zero while
the east side, especially near Campbell Creek, will likely drop
to below -10 degrees. Up into the Mat-Su Valleys overnight lows
are expect to dip into the minus single digits. Colder pockets of
temperatures below -10 degrees are forecast for the Butte, Big
Lake, Willow, and up into Skwentna.

Finally, another pattern change is forecast to develop on Sunday
as the first in a series of troughs lift northeastward into
Southcentral. This will see a return to precipitation chances,
first for Kodiak Island, and then the Kenai Peninsula. Some snow
will be possible on the western side of the peninsula, but cross
barrier flow may limit a better chance for snow until Monday.
Models are once again in little agreement in placement of synoptic
features, so lower confidence exists for where snow will be most
impactful Monday into Tuesday. The one area with higher confidence
exists is where any precipitation does fall it should fall
entirely as snow. 850 mb temperatures through early next week look
sufficiently cold across all but the offshore regions of the Gulf.


&&


.SHORT TERM FORECAST SOUTHWEST ALASKA/BERING SEA/ALEUTIANS (Days
1 through 3: Today through Monday)...

Key Messages:

* Winter Weather Advisory is in effect for the Kuskowim Delta and
  Nunivak Island through Sunday morning, primarily along the
  coast. Expect snow accumulations up to 2-5 inches, winds gusting
  as high as 40 mph, visibility reduced to one-half mile at
  times, and total snow accumulations of up to 2-3" inches.

* Winter Weather Advisory is in effect for Bristol Bay through
  Sunday morning, primarily along the coast, including Goodnews
  Bay and Platinum. Expect snow accumulations up to 2-5 inches,
  winds gusting as high as 40 mph, visibility reduced to one-half
  mile at times, and total snow accumulations of up to 2-3"
  inches.

Discussion:
A slow moving front is pushing into the Kuskokwim Delta coast and
the Western Capes of Bristol Bay this afternoon. Looking at
observations in the area, blowing snow has already begun with 35
to 40 mph east to northeasterly winds lofting snow into the air
from the preexisting snow pack, with intermittent reductions in
visibility down to one-half mile at times. A series of Winter
Weather Advisories have been issued and are in effect through
Sunday morning. By Sunday morning the front begins to weaken and
move further inland, allowing snow intensities to decrease. This
will combine with temperatures rising to nearly 30 degrees, which
should prevent blowing snow from reducing visibility to as low as
one half mile.

Out west, another low will track across the western Aleutians
into the Bering Sea, bringing a second round of rain and snow
pushing across the Aleutian Chain through the rest of this evening.
The low reaches the northern Bering by tomorrow afternoon,
bringing in a round of reinforcing snow for Southwest Alaska by
Sunday night. Snow amounts may be greater with this second round
as model guidance indicates this system is likely to be more
moisture-rich than the first one. Snow will begin to clear out
from west to east on Monday as the low sweeps across Southwest
Alaska. Behind the front, colder air once again returns to the
Bering Sea, with several embedded shortwaves leading to pockets of
enhanced snow showers and gusty winds trekking across the Sea and
the Aleutian Chain.

CQ/NM

&&


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

A rather energetic upper level pattern stretches from Eastern
Russia Districts to the Canadian Provinces, with varying amounts
of amplitude of the major features. Forecast confidence is fair
due to the smaller scale impulses moving through the pattern. A
strong trough sets up over Mainland Alaska down to the Gulf.
Ridging extends over the Bering, with a second strong trough
stretching over Kamchatka. A number of shortwaves temporarily
adjust the strengths and locations of the features through
Saturday. Arctic air returns to portions of Southern Alaska with
snow showers over the Western half of the state.

A couple of North Pacific lows work their way along the Aleutians
and Alaska Peninsula to Southcentral Alaska by Wednesday, with
the second front approaching Friday. Gusty winds and locally heavy
snow changing to mixed snow and rain over the Bering, and rain
along the Aleutians and AKPEN, Kodiak Island and on to
Southcentral Alaska coast. Snow will continue for inland
locations. Further West, a well developed low and front approach
the Western Aleutians and Bering for Thursday and Friday.
Widespread gusty winds with areas of gale force gusts move over
the Aleutians on Friday. The next round of precipitation will be
locally heavy.


Kutz

&&

.AVIATION...

PANC...VFR conditions will persist through the TAF period. Gusty
northerly winds are expected to slowly diminish through the
afternoon and evening. By Sunday, winds will be light and
variable.

-TM

&&


$$


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