Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 325 PM EST Sat Jan 5 2019 Valid 12Z Wed Jan 9 2019 - 12Z Sun Jan 13 2019 The model ensemble means are in relatively good agreement on the synoptic scale through much of the forecast period, with the 6Z GEFS mean becoming slightly more progressive with the flow over the north Pacific by late Thursday. The active storm track remains well south of mainland Alaska, with a major oceanic storm developing Wednesday night south of the Aleutians with central pressure likely below 960 mb. Over mainland Alaska, both the GFS and ECMWF indicate that a cold upper low will slowly retrograde westward across northern Alaska into northeastern Siberia through the middle of next week. This will keep a frigid air mass in place through Thursday, especially across northern Alaska and the central Interior region. Given that the ECMWF/EC mean has handled the synoptic pattern the best for areas south of Alaska over the past couple of days, we will continue to lean toward these solutions. Therefore, the latest WPC Alaskan grids were based on a weighted consensus from these model solutions: 00Z EC mean, 00Z ECMWF, and 6Z GFS with a preference to the ECMWF/EC mean. In terms of sensible weather, frigid temperatures are expected across much of the Interior and extending to the Arctic Coast at the beginning of the forecast period Wednesday, with some overnight lows in the minus 40s likely for some of the sheltered valleys! A gradual moderating trend is expected to ensue by next weekend as an upper level ridge builds in with most locations rising above zero by Saturday. Strong winds are expected for the Aleutians and the Bering Sea by Thursday and Friday as the intense oceanic storm passes just south of the Aleutians and then gradually weakens. Much of the mainland should remain mostly dry with some scattered flurries, and more organized snowfall for the Aleutians and southern coast of Alaska. 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 http://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml http://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html