Alaska Extended Forecast Discussion
National Weather Service College Park MD
658 PM EST Fri Dec 5 2025

Valid 12Z Tue 09 Dec 2025 - 12Z Sat 13 Dec 2025


...Overview...

Albeit with some shortwaves, the large scale pattern across Alaska
next week will consist of positively tilted upper troughing across
the eastern part of the state into the Gulf, with strong upper
ridging behind. The mean northerly flow and arctic surface high
pressure over the Mainland will lead to cold conditions through
much of the week especially over central and eastern Alaska.
Rounds of relatively weak low pressure systems in the Gulf/Pacific
could produce some light to moderate precipitation (mainly snow)
over Southeast Alaska, while northerly gap winds could be somewhat
strong across the Alaska Peninsula toward the western Kenai
Peninsula midweek. 


...Guidance Evaluation and Preferences...

Models show reasonably good agreement on the overall pattern 
early in the period. Troughing stretching across Southeast Alaska 
into the Pacific on Tuesday is forecast to shift east into 
midweek, while another shortwave digs through the western and 
central Mainland for a brief bout of troughing there. 
Deterministic guidance was similar enough to blend with the 
positions of these trough features, so used a multi-model blend 
favoring the ECMWF and GFS in the early period.

Then into later next week, there are some uncertainties with 
where the upper high over the Pacific/Aleutians/Bering Sea sets 
up, and with shortwaves that may round its northern side (with a 
possibly resulting surface frontal system). Recent CMC runs have 
been oriented farther north and west with the ridge's most 
anomalous heights into the Bering compared to most other guidance.
It does have some support from its ensemble mean and somewhat 
from the ICON, but this seems like a lower probability solution. 
The ECMWF was stronger with its shortwave reaching the 
northwestern Mainland compared to other guidance, and suspect the 
upper ridge may be too strong to see the shortwave erode it that 
much. Overall, increased the proportion of ensemble means in the 
model blend to half Day 7 and more Day 8 amid the increasing 
spread.


...Weather/Hazards Highlights...

Most precipitation across Alaska at least early to midweek will 
be across Southeast Alaska given Gulf of Alaska low pressure 
systems. Just light to moderate totals (mostly snow) are expected 
as heavier precipitation phases into the short range. On the 
backside of the mean surface low, northerly gap winds are possible
across the Alaska Peninsula into the waters near Kodiak Island 
and the western side of the Kenai Peninsula, with the highest 
winds expected on Wednesday. Additional northerly gap winds could 
be a threat later next week too, depending on the evolution of the
pattern. Light snow is possible across the Brooks Range and North
Slope. Other than that, surface high pressure dominating will 
lead to dry conditions. By Thursday, a round of snow may push into
the northwestern Mainland and spread across the Interior late 
week, but this is dependent on an uncertain potential shortwave 
and its surface front reflection.

High pressure will dominate much of the Mainland into the 
Panhandle next week, causing temperatures to be colder than 
(already cold) averages. Temperatures well into the -30s will be 
common in the central to eastern Interior, which is 20-40 degrees 
below average. As the upper ridging sneaks into western areas as 
the week progresses, the Aleutians into western areas of the 
Mainland should moderate somewhat closer to normal.


Tate


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