Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 640 PM EST Tue Nov 30 2021 Valid 12Z Sat Dec 04 2021 - 12Z Wed Dec 08 2021 ...Well below normal temperatures over southwestern Alaska will give way to snowy and windy conditions late this week and into early next week... ...Guidance Evaluation/Preferences... The Alaska region should become increasingly active through this weekend and into early next week as amplified troughing sends a deep cyclone across the northern Bering and into western Alaska by next Monday. This system should weaken as it moves through the interior with additional triple point low development possible along the Gulf Coast next Tuesday-Wednesday. The guidance continues to show fairly good agreement on the large scale with mainly the typical timing and detail differences in various systems. The greatest differences seem to surround the amplified trough/deep surface low into the Bering and western Mainland this weekend. Although guidance is reasonably in agreement in the upper pattern, this translates to some more significant differences at the surface among the deterministic solutions. Both the 12z ECMWF and CMC suggest the surface low may lift farther northward towards the North Slope region, while the GFS (and the ensemble means) show the low moving more eastward into the Mainland. The WPC forecast progs used a general model blend between the deterministic models for days 4-5, gradually increasing weighting of the ensemble means thereafter to help smooth out the detail uncertainties which will need more time to resolve. This approach maintains good continuity with yesterday's WPC forecasts as well. ...Weather/Hazard Highlights... Alaska should initially start very chilly with much below normal temperatures on Saturday. Daytime highs could average 20-30+ degrees below average across much of the Southwest and into interior and eastern Alaska. By Sunday, temperatures should begin to moderate as a low pressure system into the Bering Sea brings milder air from the south, along with periods of snowy and windy weather. Snow chances across western and southwestern Alaska should increase on Saturday, with the greatest threat for snow Sunday into Monday across the interior southwestern Alaska and points farther north, particularly along favored terrain enhanced regions. Guidance suggests right now moderate snowfall amounts of generally around a foot (or less) is expected, though there is potential some locations could see more. Snow should propagate into parts of southeast Alaska too, though the heaviest amounts should be confined to mountainous areas. This system should also bring rain and wind to the Aleutians and into the Peninsula region this weekend, with precipitation chances increasing again early next week across the southern coast to Panhandle as the cold front moves through the Gulf. Santorelli Hazards: - Much below normal temperatures across portions of southwestern Alaska, Fri, Dec 3. - Much below normal temperatures across portions of southwestern and interior Alaska, Fri-Sat, Dec 3-Dec 4. 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