Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 252 PM EDT Sun May 26 2019 Valid 12Z Thu May 30 2019 - 12Z Mon Jun 03 2019 Deterministic and ensemble model guidance continues to have a good handle on the overall synoptic evolution over Alaska through the medium range period. The upper level pattern favors ridging over mainland Alaska during much of the period which allows for a meandering main cyclone near the eastern Aleutians which eventually may retrograde slowly west/south owing to influence from less predictable shortwaves rounding the base of the trough. This pattern supports unsettled weather from the Aleutians to the Panhandle through most of the period, with rounds of locally heavy precipitation possible along the coast and favored terrain across the southern Mainland. Across central to northern Alaska, mainly showery activity and near to above normal temperatures are expected. Days 4-6 showed very good deterministic model agreement so a majority 00z ECMWF/12z GFS blend sufficed, with small amounts of their respective ensemble means. After this, increased the weighting of the means to mitigate smaller scale differences in the details, but the agreement was still good enough to include modest amounts of deterministic guidance. This approach maintains reasonable continuity with yesterday's WPC Alaska forecast as well as downstream over the East Pacific/CONUS. Santorelli 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