Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EST Sun Dec 24 2023 Valid 12Z Thu Dec 28 2023 - 12Z Mon Jan 01 2024 ...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 cause the deep layer flow across AK to be southerly to south-southeasterly, causing some retrogression to the moisture plume along its eastern periphery which will shift the maximum QPF expected from the AK Panhandle to south-central AK. While the guidance is in general agreement on this idea, detail issues remain, though they're less significant than this time yesterday. Aspects of the 12z ECMWF forecast across the Bering Sea late in the period/next weekend 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, 12z UKMET, and 12z Canadian early was preferred in an attempt to deal with the lingering detail 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 10-20F of moderation forecast across the board, though day-to-day trends have shown less moderation. 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