Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 417 PM EDT Fri Jun 22 2018 Valid 12Z Tue Jun 26 2018 - 12Z Sat Jun 30 2018 The beginning of this forecast period on Tuesday over the Alaska domain offers reasonable overall deterministic and ensemble mean agreement with respect to a low pressure system over the southern Bering Sea, a surface high north of the Arctic Coast, and a high pressure ridge extending northward over the Gulf of Alaska. The latest 12Z model guidance suggests that the Bering Sea low is expected to move rather slowly to the southwest mainland coast and gradually weaken. The past couple of CMC runs have been ahead of the model consensus in bringing this system westward, and the GFS is on the slower side of the guidance. By Wednesday there is more uncertainty regarding a triple point low that may develop south of the Aleutians and then move into the Gulf, with the 12Z ECMWF indicating a considerably slower evolution of that low and the GFS/CMC notably faster. This leads to greater uncertainty by the end of next week with regard to the southern Coast and the timing of any adverse weather conditions. The forecast for the Gulf region depended more on a model consensus, including the 00Z ECMWF ensemble mean, which takes this new low toward the Panhandle next Thursday. This will keep the focus for precipitation along the Aleutians and the southern Kenai peninsula, and another focus over the central/southern Panhandle. The interior will also see some isolated showers and perhaps some thunderstorms as the ridge axis slides eastward into Canada and smaller shortwaves lift northward. High temperatures in the 60s and lower 70s can be expected for most of the lower elevation locations inland, and mid 50s to lower 60s for the coastal areas, except 40s for the Arctic Coast. D. Hamrick 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