Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 657 PM EST Mon Nov 29 2021 Valid 12Z Fri Dec 03 2021 - 12Z Tue Dec 07 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... Despite the increasingly active pattern forecast to arrive by this weekend, the new guidance today appears to show enough compatibility with each other that a general model compromise should offer a good starting point through Day 8. The 12Z GFS is on the typically faster side relative to the slower 12Z ECMWF (although the 06Z GFS is slower) regarding the low pressure system moving across the Bering Sea this weekend. By early next week, the 12Z ECMWF transition to the faster side of the guidance as the low pressure system moves onshore across southwestern Alaska. This may be too fast since the 12Z EC mean is slower in comparison. The 00Z EC mean is in between the 12Z GEFS and the CMC mean. A 40% blend of the 12Z GFS/GEFS with 40% 12Z ECMWF/00Z EC mean, and 20% from the 12Z CMC/CMC mean was adopted from Days 4 to 6. Higher percentages from the ensemble means were then used for Days 7 and 8. This blend yielded a solution very similar to yesterday's WPC forecasts. ...Weather/Hazard Highlights... An energetic cold front steadily moving through the Bering Sea and the Aleutians on Friday will signal the arrival of a period of active weather for southwestern Alaska into early next week. Much below normal temperatures and mostly clear skies initially across the Southwest and interior mainland will give way to moderating temperatures as a series of low pressure systems brings milder air from the south along with periods of snowy and windy weather. It appears that western and southwestern Alaska will receive a period of snow daily starting on Friday, and the snow should become heavier each day through the weekend. The greatest threat of snow appears to be next Monday across interior southwestern Alaska where areas of enhanced snowfall are possible. Occasional rain and windy conditions are expected farther south along the Aleutians into the Alaska Peninsula by the weekend. The rain should transition to snow showers by early next week. Meanwhile, the southern periphery of Alaska down along the Panhandle can expect an increasing chance of precipitation by next Tuesday. Kong Hazards: - Much below normal temperatures across portions of mainland Alaska, Thu-Fri, Dec 2-Dec 3. - Much below normal temperatures across portions of mainland Alaska, Fri-Sun, Dec 3-Dec 5. 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