Alaska Extended Forecast Discussion
National Weather Service College Park MD
755 PM EDT Sun Oct 12 2025

Valid 12Z Thu 16 Oct 2025 - 12Z Mon 20 Oct 2025


...Active pattern continues to bring high winds across the 
Aleutians to western mainland Alaska, with moderate to heavy 
precipitation along the southern coastal areas...


...Guidance Evaluation and Preferences...

Global models continue to depict an active synoptic pattern with
more deep and fast-moving cyclones to move across the Aleutians 
toward western or southwestern Alaska through the medium-range 
period. Regarding the next Aleutian cyclone of concern through 
midweek next week, after a couple of days of gradual southward 
adjustments in the cyclone's forecast track by all models, today's
guidance support splitting the cyclone into two centers--one 
continues an eastward track into the Gulf of Alaska, while another
moves northeastward into southwestern Alaska Wednesday night or 
early Thursday. Thereafter, there is general model agreement for 
the cyclone centers to diverge further while steadily weakens.

Meanwhile, agreement remains good for a weaker cyclone to track
along the Aleutians Thursday to Friday before what appears to be
the arrival of the next deep cyclone into the Aleutians by next
weekend. The GFS as well as all of the ensemble means today favor
the cyclone center to track right along the Aleutians. This is in
contrast with the ECMWF and EC-AIFS which favor a track south of 
the Aleutians. By next Monday, there appears good indications from
both deterministic and ensemble mean consensus for yet another 
deep cyclone to quickly approach western Aleutians.

The WPC forecast package for Alaska was based on the consensus of
40% from the 12Z ECMWF/00Z and 12Z EC mean, 40% from the 12Z 
GFS/GEFS, and 20% from the 12Z CMC/CMC mean. A higher percentage
from the operational GFS and ECMWF were used for Day 4 to depict 
the double-barrel structure of the cyclone approaching 
southwestern Alaska. By Day 8, mainly the consensus of the 
ensemble means was used. Overall, this blend yielded a surface 
isobaric pattern not too different from yesterday's WPC forecast 
package.


...Weather/Hazards Highlights...

Impacts from the next deep cyclone of concern will likely
culminate on Wednesday from the Aleutians spreading quickly into 
much of the Peninsula and southern mainland with moderate 
rainfall. Nevertheless, with today's guidance favoring splitting 
the cyclone into two centers, the high wind threat from eastern 
Aleutians to southern mainland appears to have lessened on 
Wednesday given that the strongest winds are expected to occur to 
the south of the southern center. Thereafter, triple-point wave 
development over the Gulf of Alaska will likely bring a period of 
enhanced precipitation from South Central to northern Panhandle 
for the latter half of next week. By next weekend, the threat of 
high winds has continued to increase across the Aleutians given 
the latest model indications on what could be the arrival of the 
next deep cyclone. High Winds are now indicated on WPC's Day 3-7
Hazards Outlook map for all of Aleutians to South Central for 
next weekend. Elsewhere, some light amounts of high-elevation snow
and low-elevation rain are expected to reach farther north across
the northern half of Alaska in association with the remnants of 
the midweek Aleutian cyclone.

Temperature-wise, persistent southwesterly flow across the Alaska
domain will keep temperatures above normal for much of the state 
through the medium-range forecast period.

Kong




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