Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 352 PM EST Thu Nov 24 2022 Valid 12Z Mon Nov 28 2022 - 12Z Fri Dec 02 2022 ...Guidance/Predictability Assessment and Preferences... Persistent ridging is expected over Alaska sandwiched in between a large, deep layered low over northeast Asia and an increasingly full latitude trough from Nunavut into the western Lower 48 United States. This pattern favors strong high pressure systems across western Canada within the region of confluent/convergent flow aloft. Because of the amplified nature of the pattern, guidance differences are not an extreme as they can be. Overall, the 12z ECMWF is the biggest outlier across the board, even when compared to its own ensemble mean, with a weak system offshore the AK Panhandle, how close it gets with a system near the AK Peninsula, and how quickly it breaks down the AK ridge. Overall, the 12z NAEFS mean and 00z ECMWF ensemble mean favor the GFS, which features more AK ridging and a closer low track to the AK Peninsula. The WPC fronts/pressures/500 hPa heights/precipitation forecast was derived a GFS heavy blend based on the above. The remainder of the weather grids were closer to the 19z NBM, as usual. ...Weather/Hazards Highlights... An area of low pressure is expected to strengthen off the coast of the Panhandle on Tuesday due to a broad shortwave aloft. Building high pressure with pressures exceeding 1040 hPa (and temperatures 10 to 20 degrees below average) is expected over Interior Alaska and the Yukon where low temperatures below -30F are forecast. Cold air filtering southward will allow for most precipitation to fall as snow across the Panhandle early next week. Snowfall amounts are likely to exceed 8 inches as high snow-liquid ratios accompany the cold air mass. As uncertainty remains with the low track, the forecast details could change in succeeding days. Strong northerly gap winds exceeding gale force are expected on Tuesday and Wednesday behind the system over the northern and central Panhandle, and well as south-central coastal regions of Alaska due to the strong and cold high pressure system over the Interior. The strong winds will also accompany temperatures around 20 degrees below average over the Panhandle, leading to wind chills well below zero. Out to the west, the deep layer cyclone in northeast Asia will make slow progress eastward. Gales are expected across the Bering Sea on the 28th and 29th as a cyclone moves north around its eastern periphery through the western Bering Sea, with another threat for gales in the Bering Sea and Aleutians on December 1st and 2nd as another cyclone moves east into and through the Bering Sea. Rain chances and amounts are highest near the southern coast this forecast period. Clearing skies will move from northwest to southeast through mainland Alaska between the Bering Sea cyclones and the low offshore the AK Panhandle. Roth/Snell Hazards: - Heavy snow across portions of the Alaska Panhandle, Mon-Tue, Nov 28-Nov 29. - High winds across portions of the Alaska Panhandle and south-central Alaska, Tue-Wed, Nov 29-Nov 30. 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