Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 333 PM EDT Sat Aug 03 2019 Valid 12Z Wed Aug 07 2019 - 12Z Sun Aug 11 2019 ...Pattern Overview and Guidance/Predictability Assessment... Medium range models and ensembles show an overall blocky flow pattern over Alaskan and vicinity anchored by an amplified/stablizing ridge extending from the eastern Bering Sea and Western Alaska down through the Alaksan Peninsula and western Gulf of Alaska. Guidance is generally well clustered into Wednesday and a composite solution seems reasonable. However, significant forecast track/emphasis spread with a series of embedded weather focusing systems working around this feature becomes especially evident days 5-8. Given uncertainty, a compatable 12 UTC GEFS mean and 00 UTC ECMWF ensemble mean blend is preferred over more varied deterministic model gudiance. This forecast strategy was collaborated with local WFOs. In this pattern, an amplified upper level trough and surface low/system is slated for an uncertain lift over the Bering Sea Wed-Fri on the western ridge periphery. Organized precipitation through the Bering Sea and Aleutians weakens into western Alaska. More amplified upper trough development may reach the western Bering Sea by next weekend with deeper surface low/frontal genesis, with eastward progression slowed by the resilient downstream ridge. A series of mid-upper level trough energies to round the top then dig southeastward to the lee of the ridge over the interior then Southeast Panhandle. Expect a cool and showery pattern focused by modest but renewing northeast Gulf of Alaska surface system developments. Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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