Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 509 PM EST Sat Dec 23 2023 Valid 12Z Wed Dec 27 2023 - 12Z Sun Dec 31 2023 ...General Overview/Guidance Evaluation/Preferences... A deep layer low across portions of the Bering Sea is expected to be replaced by a more southern system, closer to the Aleutians with time, with amplified ridging across much of northwestern North America, which could be degraded somewhat at times as shortwaves pass over its apex. This will change the deep layer flow across AK from southerly to south-southeasterly, causing from retrogression to the moisture plume along its eastern periphery. While the guidance is in general agreement on this idea, detail issues are non-trivial, particularly across the Bering Sea, Gulf of AK, and adjacent northeast Pacific. Aspects of the 12z ECMWF forecast across the northeast Pacific and Gulf of AK kept its usage this cycle as a minimal/minority weighting. For the pressures, fronts, 500 hPa heights, and the QPF, a compromise of the 12z GFS, 12z ECMWF, and 12z Canadian early was preferred in an attempt to deal with some of these issues, with an increasing lean towards the 12z NAEFS/00z ECMWF ensemble means with time. The remainder of the grids were more weighted towards the 19z NBM, as usual. ...Weather/Hazards Highlights... The expected flow pattern leads to some confidence in several inches of liquid equivalent precipitation across the southern extremities of AK, with snow anticipated initially even near the coast of mainland of AK due to the cold air mass in place on Tuesday -- before snow chances retreat back into the interior and at some elevation as temperatures moderate. A broad warming is expected to take hold of AK, with 10-30F of moderation forecast across the board. Out in the open northeast Pacific, Gulf of AK, Bering Sea, and the Aleutians, periods of gale to storm-force winds are expected as cyclones with seasonal depth pass by/through the region and cold air across the interior leads to periods of enhanced gap winds in spots across the AK Panhandle. Roth 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