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