Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 734 PM EDT Tue Mar 26 2024 Valid 12Z Sat Mar 30 2024 - 12Z Wed Apr 03 2024 ...Late Week/Holiday Weekend One-Two Storm Punch to offer Wind/Wave/Coastal Flooding and/or Snow/Rain Threats from the Aleutians through Southwest and Southern Alaska... ...Guidance Evaluation and Preferences... The latest global guidance remains broadly clustered through Sunday morning as does their respective ensembles. Consensus favors a trough over the Chukchi/Bering Seas that makes its way east across the Aleutians and Gulf of Alaska that will eventually weaken/erode the riding along Southeast Alaska and western Canada. In general, models differences are mostly smaller scale. Maintained continuity by starting with a combo of the ECWMF, GFS, CMC and UKMET through the weekend before including/incrementally increasing weighting of the GEFS/EC ensemble means through the end of the extended period. The means highlight a cooling Mainland as Arctic stream upper trough energy works to dig southward and potential/eventual phasing to some degree with Pacific stream energies into the Gulf of Alaska and associated cold low developments offshore to monitor. ...Pattern Overview and Weather/Hazards Highlights... There continues to be a good signal that an amplified upper trough and an associated surface low pressure system will track/develop from a position near Japan to across the northwest Pacific to near the Aleutians Thursday to offer turbulent maritime conditions and swirling winds and rains. This storm and frontal system is likely to work northeastward into the Bering Sea and support high winds/waves and potential associated coastal flooding threats up the coast of western/Southwest Alaska Friday into Saturday before losing this influence offshore. Meanwhile, guidance persists in strongly supporting a solution with robust development of a trailing frontal wave back over the north Pacific that is now slated to lift northward toward the Alaska Peninsula Saturday as a potentially potent storm/high winds threats, with subsequent track into Southwest Alaska and into an unsettled/snowy Interior while slowly weakening. This energetic scenario would focus a heavy snow threat over portions of Southwest Alaska and into the Alaska Range. There would also be a heavy rainfall and more inland/terrain heavy snow threats as fueled by a channeled/deepened lead Pacific moisture feed up into the Alaska Peninsula/Kodiak Island and south-central Alaska, and to a much lesser extent Southeast Alaska through the weekend. Daily accumulations of 1 to 3+ inches may be possible. Campbell/Schichtel 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