Alaska Extended Forecast Discussion
National Weather Service College Park MD
708 PM EDT Mon Sep 29 2025

Valid 12Z Fri 03 Oct 2025 - 12Z Tue 07 Oct 2025

...Synoptic Overview...

In the upper levels, an anchor low/trough will be in place
generally across the Chukchi Sea throughout the period. A series
of strong troughs will rotate eastward to the south of this anchor
low, which will support the development of lows ahead of the
trough that will keep the weather unsettled over the Bering and
much of western Alaska. The biggest low will cross the Aleutians
Friday, then move northeast over the middle of the Bering, where
it will peak in intensity. The low will then weaken as it moves to
the Bering Strait or far western Alaska Sunday and Monday. A new
low races east across the Bering Monday into Tuesday, merging with
the first low. A weak low over the Gulf Friday will quickly move 
inland Friday night into Saturday over the Panhandle, then ridging
will make for more tranquil, if still cloudy weather to start the
upcoming workweek.

...Guidance Evaluation and Preferences...

While the track of the Bering low has stabilized from previous
days, tracking from the western Bering to between St. Matthew &
Nunivak Islands, then up western Alaska to the Chukchi Sea, the
guidance is in less agreement on how fast it will move and how
strong it will be. In keeping with continuity, the 00Z EC and 12Z
CMC were used, which keep the low on that track while remaining at
a good consensus of a peak intensity in the mid-970s followed by
weakening and eventual merger with a secondary low by Monday and
Tuesday near the Bering Strait. The other guidance was generally
stronger, further west, and faster than this blend. Ensemble
guidance in the form of increasing use of the ECENS was used for
the D7/Monday and D8/Tuesday periods, as the guidance is in poor
agreement on the incoming Kamchatka low that races east across the
northern Bering. Thus, a 50-50 blend of the 00Z EC and 12Z CMC was
used through D6, gradually blending in ECENS to a 60% ECENS and
20-20 split of the CMC/EC by D8. 

...Weather/Hazards Highlights...

There are no weather hazards to highlight for the period. 

There will be numerous areas to watch. As the big Bering low 
rapidly deepens Friday as it crosses the Aleutians, winds may gust
at times to near the high wind criteria, especially on the east 
side of the low over the Central Aleutians. As the low approaches 
southwest Alaska, some amount of dynamic fetch may allow seas to 
grow to high surf levels in Bristol Bay, where it appears the 
greatest likelihood for prolonged onshore flow will be. Higher 
elevation snow will impact the Aleutian, Kenai, and eventually 
Chugach Ranges in southern Alaska, but freezing levels will remain
high enough that the passes will not be affected. Heavy rain will
be possible at times with the strongest upslope into those same
coastal ranges at the lower elevations, but sustained/long-
duration heavy rain is not expected.

&&

Wegman



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