Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 158 PM EDT Sun Mar 31 2019 Valid 12Z Thu Apr 04 2019 - 12Z Mon Apr 08 2019 Models and ensembles reasonably agree that a positively tilted upper trough across western and northern AK will deepen as a piece of energy slowly drops down its axis into the Bering Sea. The cooling temperatures aloft associated with the strengthening mid- to upper-level trough will slowly transition clear skies early on to cloudy conditions by next weekend across mainland AK and rainfall in southeast AK and the panhandle is expected to slowly increase in amounts and coverage from Friday through next weekend. Ridging is expected to persist on either side of the trough across Siberia and western Canada. Guidance is not in perfect agreement with how the upper low drops down the trough, but is reasonably close; no significant outliers were noted. The WPC product suite was primarily derived from a composite blend of the 00z bias-corrected NAEFS mean, 00z ECMWF ensemble mean, 00z ECMWF, 06z/12z GFS, and 00z Canadian guidance. This pattern will hold the main Pacific storm track south of Alaska/the Gulf of AK from Thursday through next Monday. The potential phasing of systems passing around the base of the upper trough could lead to more northward and deeper low pressure systems closer to Alaska sooner or later, which needs to be watched on later runs. Precipitation will be mainly limited to parts of the Aleutians closer to the storm track, along with the AK Panhandle and southern coastal Alaska. Roth/Schichtel Bullet points from the WPC Days 3-7 Hazards chart can be found 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