Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 134 PM EST Sat Dec 01 2018 Valid 12Z Wed Dec 05 2018 - 12Z Sun Dec 09 2018 ...Guidance Assessment... The latest deterministic models are not providing guidance that is particularly consistent from run to run nor compared to their respective ensemble means days 4-8 at small-medium scales. While each of the varied individual model/ensemble member solutions are possible within a more similar larger scale flow pattern, prefer to maintain better consistency with reasonably compatable ensemble means until a more common solution emerges. Forecast spread is especially evident over the Arctic, but also from the Pacific/Bering Sea into the mainland. The WPC Alaskan medium range product suite was accordingly derived from the 06/12 UTC GEFS mean, 00 UTC ECMWF ensemble mean and blended/composite guidance from the 12 UTC National Blend of Models. ...Pattern Overview and Weather Highlights/Hazards... The WPC Alaskan medium range period begins with a rebuilt/amplified upper ridge extending from the southeast panhandle to the Interior/North Slope midweek, and that feature may prove difficult to dislodge into next weekend. An upstream closed upper level low and main surface low will weaken/shift into the southeast Bering Sea Wednesday/Thursday and an associated threat of heavy precipitation will continue for southwest/western Alaska with the eastward progression of the system blocked by the downstream ridge. Southerly moist lead fetch will meanwhile fuel widespread precipitation into the southern Alaskan tier. System genesis underneath will then work into the Gulf of Alaska later next week into next weekend to support stormy conditions/heavy precipitation potential for maritime interests and inland back into the southern Alaskan tier, but with the bulk of supporting energies aloft tending to focus increasingly to the south of the state next weekend. Schichtel WPC medium range Alaskan products including 500mb, surface fronts/pressures progs and sensible weather grids can be found at: http://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif http://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html