Alaska Extended Forecast Discussion
National Weather Service College Park MD
629 PM EST Sun Dec 7 2025

Valid 12Z Thu 11 Dec 2025 - 12Z Mon 15 Dec 2025


...Overview...

The synoptic-scale upper pattern across Alaska through the
medium-range period will likely feature an amplifying omega block
with an increasingly pronounced warm core high anchoring over the
Bering Sea. Meanwhile, an arctic surface high will remain lodged 
against the Alaska Range under the eastern branch of the omega 
block sustained by upper-level convergence. This pattern will 
effectively prevent strong Pacific cyclones from reaching the 
Alaska domain. A frontal low should manage to round the northern 
edge of the omega block late next week while another low pressure
system south of the block should be edging closer to the southern
portion of the Alaska Panhandle this weekend into early next 
week.


...Guidance Evaluation and Preferences...

The ensemble means from major global models are in favor of the
above-mentioned synoptic scale pattern through the medium-range
period. The ECMWF and Canadian models have been favoring a more
pronounced and farther north placement of the closed upper high
this weekend over the Bering Sea than the slightly weak and more
southern placement shown by the GFS. On the other hand, the EC-
AIFS favors the GFS solution.

For late this week, the Canadian model and EC-AIFS have led the 
way of allowing a frontal low pressure system to push eastward 
through the northern edge of the omega block across the Arctic
Ocean. Both the ECMWF and GFS have followed suit with this 
scenario since yesterday. The better-defined and better model 
agreement on this scenario have led to more widespread and higher
snowfall amounts across northwestern Alaska to the North Slope 
Friday and Saturday.

To the south of the Gulf of Alaska, there has been a trend for the
low pressure system(s) to be better defined as it/they gradually 
edge(s) toward the southern portion of the Alaska Panhandle this 
weekend into early next week, which also has led to an upward 
trend in the QPF for this region.

The WPC medium-range forecasts for Alaska were based on the 
consensus blend of 25% from the 12Z GFS/GEFS, 55% from the 12Z 
ECMWF/00Z EC mean, and 30% from the 12Z CMC/CMC mean. This blend 
yielded a solution fairly compatible with yesterday's forecasts 
but with notable differences across the Arctic Ocean and the 
northeastern Pacific.


...Weather/Hazards Highlights...

With the omega block over the Bering Sea forecast to amplify
further through the medium-range period, no strong low pressure 
systems are expected to impact the Alaska domain through the
medium-range period. Nevertheless, snow that has been forecast 
for northwestern Alaska to the North Slope from Friday to
Saturday has trended more widespread and slightly heavier due to a
better-defined frontal low now forecast to pass north of Alaska
during that time frame. Likewise, a better-defined low pressure
system forecast to approach southern Alaska Panhandle has also
resulted in higher precipitation chances for this coming weekend
into early next week for that region.

In the vicinity of eastern Aleutians to the Alaska Peninsula, gap
winds should be ongoing from Wednesday into Thursday between the 
building high across the Bering Sea and a low pressure system 
passing well south of the Gulf of Alaska. By the weekend, 
increasing pressure gradient between the continued strengthening 
high and the low pressure system approaching the southern 
Panhandle will raise the likelihood of gap winds across the same 
region of the eastern Aleutians to the Alaska Peninsula.

Otherwise, an arctic surface high is forecast to remain anchored 
across mainland Alaska to keep it frigid and dry south of the 
Brooks Range. Temperatures down into the -30s will be common 
across interior Alaska, with the coldest readings into 40 below 
zero midweek for the Yukon Flats and near the Canadian border in 
eastern interior section. A Hazardous Cold area has been 
introduced for the northern section of the Alaska Panhandle for 
Dec 10 near the Canadian border in the vicinity of Skagway. In 
contrast, temperatures could exceed 20 degrees above normal for 
the North Slope and western portion of Seward Peninsula. The 
Aleutians will also be somewhat milder than normal through the 
medium-range 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