Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 725 PM EDT Wed Mar 27 2024 Valid 12Z Sun Mar 31 2024 - 12Z Thu Apr 04 2024 ...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... Consensus keeps a general troughiness over the Bering/Aleutians/Gulf region with multiple impulses moving through the flow and the weakening of ridging over Southeast Alaska and surrounding area; however the model spread has not improved much beyond the start of the week resulting in an average/below average confidence on the specifics. Maintained continuity by starting with a combo of the ECWMF, GFS (12Z/6Z), CMC and UKMET through Monday night/Tuesday morning before including/incrementally increasing weighting of the GEFS/EC ensemble means through the end of the extended period. The means comprised of 60% by the end of the forecast period to account for the noise in guidance. 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... High winds/waves and potential associated coastal flooding threats up the coast of western/Southwest Alaska will likely be ongoing from Friday/Saturday before losing this influence offshore over the weekend. Meanwhile, guidance persists in strongly supporting a solution with robust development of a trailing frontal wave back over the north Pacific that suggests it will 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. 0.75 to 3+ inches may be possible along the southern coastline and points adjacent this weekend with lighter amounts lingering into next week. Campbell 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