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FXAK02 KWNH 082313
PMDAK

Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
612 PM EST Fri Nov 08 2024

Valid 12Z Tue Nov 12 2024 - 12Z Sat Nov 16 2024

...Strong Bering Sea storm could bring coastal impacts to
Southwest Alaska later next week...

...Overview...

Initially, a low pressure system over the North Pacific will pass
south of the state Tuesday and Wednesday as a relatively weak
Arctic low enters the Bering Sea. This Arctic low will quickly
weaken as a more potent Pacific storm system approaches the Bering
Sea from the southwest. The second, stronger low will move into
the Bering Sea on Thursday and could create hazardous conditions
in Southwest Alaska. This system is forecast to develop a triple
point low that will move across southern Mainland Alaska Friday
into Saturday.


...Guidance Evaluation/Preferences...

Models continue to show good agreement through mid-next week,
leading to above average predictability in this time frame. Model
spread increases for the second half of next week, but still
showing near average predictability. The most significant
uncertainty continues to surround the strong Bering Sea storm
system and it`s evolution over Alaska late next week, but
deterministic models are beginning to show better agreement on
timing and location of this system and ensemble means from the
GEFS/ECENS/CMCE are well clustered during this time frame. Models
have also begun picking up on signals that a triple point low may
form with this system, which may focus impacts over Southcentral
and Southeast Alaska next weekend.

Deterministic model guidance from the GFS/ECMWF/CMC/UKMET made up
a majority of the WPC forecast blend Tuesday through Thursday when
there is good agreement, then ensemble means from the
GEFS/ECENS/CMCE held the majority for Friday and Sunday as model
spread increased. Some deterministic guidance remained in the
blend during the later half of the period, with slightly more
emphasis on the ECMWF, which showed better consistency with the
ensemble means.


...Weather/Hazards Highlights...

The low passing south of the state early/mid next week will be far
enough south that impacts to Alaska will be minimal. There may
only be some gusty winds and light precipitation in the far
southern portions of Southeast Alaska. After this system passes,
the focus will shift to the Bering Sea as a stronger storm system
approaches. Hazardous weather potential will focus over portions
of Southwest/Western Alaska on Thursday, especially in areas
susceptible to coastal impacts. Strong onshore winds may result in
coastal flooding, and heavy precipitation may also be a concern as
a plume of pacific moisture aims for Southwest Alaska. The system
will push east on Friday and Saturday, and winds should decrease
as the system moves farther inland. Models have been showing a
triple point low forming and focusing moisture over South-central
and Southeast Alaska, which could result in some heavier
precipitation in these regions, especially along the coastal
terrain.

Arctic high pressure north of the state will usher in colder
temperatures next week, with a cooling trend expected to persist
through the middle of the week. High temperatures will drop 5-10
degrees below average for most of Alaska by Wednesday, and the
coldest temperatures will focus from the Brooks Range down through
Interior Alaska. Temperatures may start to moderate back towards
normal later next week as a more moist Pacific air mass moves into
the region.


Dolan


Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html

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