Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 227 PM EDT Mon Aug 05 2019 Valid 12Z Fri Aug 09 2019 - 12Z Tue Aug 13 2019 ...Guidance/Predictability Assessment and Weather/Threats Highlights... Models and ensembles continue to depict an overall blocky medium range flow pattern over Alaska and vicinity anchored by an amplified ridge extending from the eastern Bering Sea and Alaskan west coast down through the Alaksan Peninsula and far southwestern Gulf of Alaska. Guidance is generally well clustered into Friday when a composite solution seems reasonable. However, significant forecast track/emphasis spread and run to run variances with a series of embedded weather focusing systems working around this feature again become 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. The forecast strategy was, as always, collaborated with local Alaskan WFOs. In this pattern, an amplified upper level trough and surface low/system remains on track to lift into the Bering Strait by Fri on the western periphery of the main ridge. Organized precipitation through the Bering Sea weakens into the western Alaska mean ridge position aloft. More amplified upper trough development is still expected to reach the western Bering Sea by next weekend with deep surface low/frontal genesis, with eastward progression slowed by the resilient main ridge. Well downstream, 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 reinforcement of a cool and showery pattern with surface frontal surges as 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 No significant hazards are expected over Alaska during this forecast period. 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