Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 617 PM EDT Thu May 06 2021 Valid 12Z Mon May 10 2021 - 12Z Fri May 14 2021 ...Guidance/Predictability Assessment... Models and ensembles show a reasonably similar larger scale pattern evolution through medium range time scales, but as is often the case offer increasingly evident over time run to run differences with small-mid scale embedded weather systems. The 12 UTC GFS/ECMWF/UKMET/Canadian model solutions seem well clustered day 4/Monday and a composite seems to produce a good forecast starting point. Gradually increasing forecast spread and decreasing predictability with these embedded systems seem best mitigated by a steady forecast shift toward a composite of still reasonably well clustered guidance of the 12 UTC GEFS/NAEFS/ECMWF ensemble means and the 19 UTC National Blend of Models days 5-8 (Tuesday-next Friday). This forecast strategy maintains decent WPC product continuity. ...Weather/Threats Highlights... Lead upper trough energies and moderate precipitation focusing surface lows/frontal weather systems will work from the Aleutians and the Alaskan Peninsula into the Gulf of Alaska and toward southern/southeastern Alaska early-mid next week, undercutting a warming/stabilizing mainland upper ridge. Then upstream, amplified/closed upper trough energy is slated to track over the southern Bering Sea/Aleutians mid-later next week and deepening low pressure could support unsettled maritime conditions and some inland wrapping organized rains/winds across the region, then downstream into the Alaskan Peninsula/Southwest Alaska by late in this forecast period. Schichtel Hazards: No significant hazards are expected over Alaska during this forecast period. 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