Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 630 PM EDT Sat Jun 12 2021 Valid 12Z Wed Jun 16 2021 - 12Z Sun Jun 20 2021 ...Guidance/Predictability Evaluation... The WPC Alaskan medium range product suite was primarily derived from a blend of best clustered guidance of the 12 UTC GFS/ECMWF, 12 UTC GEFS/ECMWF ensemble means and the 19 UTC National Blend of Models Day 4-8. However, deemphasized the deterministic models over time due to increased variability and continuity issues with embedded systems in a pattern with lowering predictability. Manually adjustments were applied mainly to offshore lows to maintain strength consistent with predictability and upper support to offset weakening inherent to the blending process/forecast spread. ...Weather/Threats Highlights... Lingering northern stream upper troughing from the Arctic Ocean into northern Alaska will support unsettled maritime weather, but minimal onshore precipitation next week as upper ridging builds northward from a warmed Interior. Meanwhile, an active southern branch storm track will progress near/just south of the Aleutians and a series of complex/uncertain lows and frontal systems will focus unsettled weather over the region, then downstream across the Gulf of Alaska with system proximity and to a lesser extent coastal southern and southeast Alaska. 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