Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 326 PM EDT Mon Jun 25 2018 Valid 12Z Fri Jun 29 2018 - 12Z Tue Jul 03 2018 An upper low is forecast to meander over northeastern Russia as ridging builds south of the Gulf of Alaska. In between, a lead upper low over the Aleutians will weaken and slide eastward as heights build in its wake. The models/ensembles were in relatively good agreement through the medium range but the 00Z ECMWF was most different from the GFS and ensemble means after about Saturday. The challenging part to the forecast lies in how the north central Pacific pattern unfolds as ridging builds into Japan from the southeast. Prefer to have weaker rather than more defined systems with time due to the flatter pattern and the ECMWF seemed to develop backside energy just too much for the pattern. 12Z GFS formed most of the detail to the forecast. This brings in milder air to southcentral areas and a drier trend overall but with a daily chance of some showers/storms over the interior as well. Fracasso 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 www.wpc.ncep.noaa.gov/alaska/akmedr.shtml http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html