Alaska Extended Forecast Discussion
National Weather Service College Park MD
709 PM EDT Thu Oct 23 2025

Valid 12Z Mon 27 Oct 2025 - 12Z Fri 31 Oct 2025


...Stormy pattern into the Gulf of Alaska and South/Southeast 
Alaska next week... 


...Guidance Evaluation/Preferences...

There is good guidance agreement with one major exception through
medium-range time scales overall for the Alaskan domain in an 
increasingly stormy pattern. A composite blend of best clustered 
12 UTC GFS/ECMWF/UKMET models seems reasonable into early next 
week for best details, especially important as ample upper trough 
energies translate robustly downstream from the Bering Sea to the
Gulf of Alaska. This blend works well for most areas Tuesday into
Wednesday except for the quite different handling of a lead deepening
north Pacific storm system with an envelope of solutions ranging 
from lifting northward into the eastern Gulf of Alaska to a more 
eastward path with much less robust wind/wave and precipitation 
threats for Southeast Alaska. WPC progs show a reasonably deep 
storm near the centroid position between the farther north tracks 
of the 12 UTC GFS/Canadian and more southward solutions of the 12 
UTC ECMWF/UKMET after collaboration with WFO Juneau. This scenraio
will be re-evaluated as the variance signal improves with newer 
guidance. While upstream upper flow seems to favor northward lift 
of the storm, lower resolution ensemble and machine learning 
guidance has been more reluctant and mixed to embrace that path.

Switched preference to a GFS/ECMWF/Canadian ensemble mean blend
for mid-later next week in an emerging stormy pattern along/south
of the state with overall above normal predictability. This blend
was used to mitigate small-mid scale variances still present at 
these longer time frames, but less evident in the smoothed 
ensemble means. Expect deep and impactful system development within
a renewed and impactful stormy pattern from roughly the Aleutians
downstream to the Gulf of Alaska and southern/Southeast Alaska.

...Overview and Weather/Hazards Highlights...

An amplified northern stream upper low/trough will shift robustly  
southeastward from the Bering Sea to the Gulf of Alaska early next
week. Expect unsettled weather for coastal Southwest Alaska 
into the Aleutians and the Alaskan Peninsula/Southern Alaska. 
Inland impacts do not seem to reach normal hazards thresholds for 
most areas, but would include more susceptible Southeast Alaska 
recovery areas. However, downstream northern Gulf of Alaska 
system development with moderate precipitation along with 
wrapping and gap wind potential inpacts. In this pattern, a lead 
upper low/trough set to linger over the Gulf of Alaska into early next
week will quickly lose influence. Meanwhile, an aforementioned 
storm in a renewed stormy pattern to the west is then expected to
emerge/evolve to threaten the Aleutians before gaining strength 
and evolving steadly downstream mid-late next week across the 
Gulf of Alaska. This would set the stage for significant maritime
hazards and lead into end of month heavy precipitation and high 
winds for South/Southeast Alaska including heavy mountain snows.

Schichtel




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