Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 602 PM EST Wed Dec 25 2024 Valid 12Z Sun Dec 29 2024 - 12Z Thu Jan 02 2025 ...Arctic cold overspreads much of the Mainland with the coldest temperatures of the season for the western/central Interior... ...Gusty winds possible for Cook Inlet and surrounding areas next week... ...Overview with Guidance Evaluation and Preferences... The extended range period over Alaska begins with ridging across the Mainland and an elongated trough, anchored by a closed low, over the Aleutians. The main weather systems of note will be a train of shortwaves as they track south of the Aleutians into the Gulf of Alaska. This pattern should hold into early next week until the Aleutians low weakens in favor of another strong system to its west, and the upper high over the Mainland retreats northward. Much of the pattern uncertainty lies with the individual systems/shortwaves south of the Aleutians into the Gulf. The guidance continues to show varying degrees of strength and track of these systems, which depending on how close they track towards the coast, would have important implications on sensible weather. A stronger area of low pressure will enter the Gulf around Tuesday-Wednesday, but again with significant uncertainty in the details. This low should be reinforced/maintained into mid next week as stronger ridging begins to build back in over the eastern Aleutians. The WPC forecast for today leaned heavily on the deterministic models through about day 5/Monday, with some slight lean towards the ECMWF which was closest to the ensemble means. After Monday, uncertainty increases and it seemed most prudent to trend quickly towards the ensemble means late period. In general, this maintains good continuity with the previous WPC forecast. ...Weather/Hazards Highlights... A train of low pressure systems into the Gulf will keep the Aleutians to Southern Coast to Southeast generally unsettled and wet, though rainfall should be mostly light to moderate in nature. A stronger low pressure system into the Gulf Tuesday into Wednesday may provide some additional enhancement and the possibility for stronger to gustier winds, particularly for the Kenai Peninsula, Cook Inlet area, and possibly Kodiak Island. Winds and precipitation are not expected at this time to be hazardous. Interior to northern Alaska should be dry most of the period. As for temperatures, a surge of arctic air is expected to be in place over much of mainland/interior Alaska associated with troughing over the Arctic. Temperatures could be 20-30+ degrees below average, with actual temperatures closer to -30 degrees, or more, in some locations and especially the North Slope this weekend. This air mass should moderate gradually from west to east into next week but still remain close to or below normal. Meanwhile, mild and near to above normal temperatures should prevail across the Aleutians, southwest Alaska, and the Southern Coast/Southeast. Santorelli 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