Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 513 PM EST Fri Feb 5 2021 Valid 12Z Tue Feb 9 2021 - 12Z Sat Feb 13 2021 ...Overview and Guidance/Uncertainty Assessment... An upper level low that is expected to initially be over northeastern mainland Alaska on Tuesday is expected to slowly drift westward through the middle of the week. A narrow ridge axis will likely exist across the Aleutians and Bering Sea region that extends northward from the North Pacific. There is the increasing possibility that a strong surface low could affect the western Aleutians by Wednesday and into Thursday. It is also interesting to note that a highly anomalous surface high just north of the Arctic Coast, on the order of 1060+ mb, could come close to setting high pressure records for Barrow (Utqiagvik). In terms of the models, the 12Z GFS stood out from the model consensus by the end of the week with keeping the core of the upper low farther south across southwestern Alaska, whereas the CMC/ECMWF and the ensemble means favored a solution closer to the Arctic Coast. Elsewhere, there are numerous model differences with the overall synoptic scale pattern with lower than average forecast confidence by Thursday and beyond, and incorporating the CMC/ECMWF/some GFS along with some of the ensemble means served as a good starting point, along with some previous WPC continuity. ...Weather/Hazards Highlights... Coastal low pressure over the Gulf of Alaska will tend weaken through Wednesday, and this will focus periods of snow across the southeastern coast and the southeastern Panhandle. It appears that the heaviest precipitation is most probable around Wednesday for this region, and potentially for the central and western Aleutians depending on the track of the next storm system. Depending on the eventual strength of that storm, gusty winds could eventually become a concern, but confidence is currently limited. Today's guidance preferences would yield mainly light to moderate activity for most of this time period. In terms of temperatures, it will likely be bitterly cold across much of central and northern Alaska with widespread 30 below readings expected north of the Alaska Range, and perhaps as extreme as 50 below for the normally colder locations. Hamrick 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 Hazards: - Much below normal temperatures across portions of mainland Alaska, Sun-Thu, Feb 8-Feb 11. 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