Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 654 PM EST Thu Mar 02 2023 Valid 12Z Mon Mar 06 2023 - 12Z Fri Mar 10 2023 ...Heavy precipitation to continue next Monday across the eastern Aleutians as heavy snow and gusty winds impact portions of western mainland... ...Pattern Overview with Model Guidance/Predictability Assessment and Weather Highlights... A sustained stream of moisture from the Pacific is forecast to continue impacting a relatively narrow zone from the eastern Aleutians northward through western Alaska as the medium-range period begins early next Monday. This is in response to an anomalous ridge of high pressure forecast to extend further northward through mainland Alaska and into the Arctic Ocean as low pressure waves track from south to north along a quasi-stationary front across the Bering Sea and into the Arctic Ocean. Despite some east/west wavering of the general low tracks in the forecast guidance, there has been very consistent agreement on placing a relatively narrow band of heavy precipitation across the eastern Aleutians as well as the western mainland into early next week. Precipitation should be mainly rain for the lower elevations over the eastern Aleutians while heavy snow is expected to impact the higher elevations. Meanwhile, snow is expected to be the main precipitation type across western Alaska, with heavy snow over the southern half of the Seward Peninsula as well as the western extension of the Brooks Range across the Lisburne Peninsula toward Point Hope. Winds are forecast to gradually moderate by Monday as the highly amplified upper-level pattern begins to show signs of breaking down. A slow drying trend is forecast for the precipitation-affected areas through the middle of and into late next week as ensemble means continue to indicate further break down of the highly amplified pattern. Periods of light snow can be expected to move across the North Slope from mid- to late week as a piece of the anomalous ridge breaks off into an upper-level high over southern Alaska, then shifts slowly westward into the Bering Sea by late week. Well above normal temperatures are forecast to expand northward and eastward across mainland Alaska early next week with the warmest anomalies expected over the North Slope. The warmth will be not as anomalous across southwestern Alaska but above freezing high temperatures are forecast to change the snow to a wintry mix or plain rain near the coast. In contrast, temperatures across the Panhandle will likely be colder than to much colder than average, especially early next week, near the southern periphery of an arctic high pressure system centered over Yukon. This general situation is forecast to prevail but with a gradually moderating trend for both the warmth in the north and the cold over the Panhandle as next week progresses. The WPC forecast package was derived using 40% from the 12Z ECMWF/EC mean, 40% from the 12Z GFS/GEFS, and 20% from the 12Z CMC and CMC mean. The results are quite compatible with yesterday's forecast package, with a faster northward motion of a low pressure wave across the Bering Sea next Tuesday. Kong - Heavy precipitation across portions of mainland Alaska and the Aleutians, Sun-Mon, Mar 5-Mar 6. - Heavy snow across portions of mainland Alaska, Sun-Mon, Mar 5-Mar 6. - High winds across portions of mainland Alaska, Sun, Mar 5. - Much above normal temperatures across portions of mainland Alaska, Mon-Tue, Mar 6-Mar 7. - Much below normal temperatures across portions of the Alaska Panhandle, Mon-Tue, Mar 6-Mar 7. 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