Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 621 PM EST Thu Dec 02 2021 Valid 12Z Mon Dec 06 2021 - 12Z Fri Dec 10 2021 ...Heavy snow and high wind threat from western to southern Alaska into early next week... ...Overview and Guidance Evaluation/Preferences... The Alaskan weather pattern will become increasingly active through this weekend and into early next week as amplified upper troughing brings a deep cyclone and reinforcing energies across the Bering Sea to western Alaska. The system should weaken as it tracks through the Mainland though additional triple point development along the Gulf Coast should send a cold front towards the Panhandle region mid week. Meanwhile, an additional upper trough energies tracking towards the Bering Sea and Aleutians by later next week may support another deep low pressure system into the region, albeit with more uncertainty. Guidance shows relatively good agreement through Day 4/5 (Monday/Tuesday) and a composite of the well clustered 12 UTC GFS/ECMWF/Canadian seems to offer a reasonable solution with above normal detail and predictability. Forecast spread and uncertainty increases quickly days 6-8 (Wed-next Friday), especially surrounding the next main low towards the Aleutians and Bering Sea. The GFS/CMC and ensemble means still support lifting the low to the Bering Sea, while the ECMWF tracks the low along/south of the Aleutians. Given trends and uncertainty, the WPC forecast progs used a blend of the reasonably compatible GEFS/ECMWF ensemble means. This approach maintains good continuity with yesterday's WPC forecasts as well. ...Weather/Hazard Highlights... The Bering Sea cyclone will usher in a much more active weather pattern across Alaska consisting of windy and snow conditions. Much of western Alaska will experience snow into Monday, with the greatest threat across parts of the Seward Peninsula and southwestern Alaska. Current guidance suggests some locations could see upwards of a foot of snow, along with a period of gusty winds as the low moves inland on Monday. Increasingly wet weather will also move into parts of the Southern Coast and southeast Alaska Monday into Tuesday again with a threat for locally heavy snows, especially across the favorable terrain. The cold front propagating through the Gulf should bring increased rain chances to the Panhandle mid week next week with rain again threatening the Aleutians as well with the next low pressure system into the region. After a period of much below normal temperatures, conditions should finally begin to moderate from west to east by the start of the extended period on Sunday as the Bering Sea low brings milder air in from the south. By next Monday, much of interior and northern Alaska should see temperatures near or above normal, with the greatest anomalies likely across parts of western Alaska and the North Slope region before some potential for western Alaskan cooling later next week. Schichtel Hazards:- Heavy precipitation across portions of mainland Alaska, Mon, Dec 6. - Heavy snow across portions of mainland Alaska, Sun, Dec 5. - High winds across portions of mainland Alaska, Sun-Mon, Dec 5-Dec 6. - Much below normal temperatures across portions of mainland Alaska, Tue-Thu, Dec 7-Dec 9. 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