Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 658 PM EST Fri Dec 4 2020 Valid 12Z Tue Dec 8 2020 - 12Z Sat Dec 12 2020 ...Guidance and Uncertainty Assessment... The deterministic and ensemble guidance is in relatively good agreement that the strong Gulf low over the Gulf region during the short-term period will be rapidly weakening by Tuesday, and also in good agreement that high pressure north of the Arctic Coast will keep the weather pattern cold and dry across the Interior and North Slope region. There is greater model uncertainty with the next strong low pressure system approaching the Aleutians by Wednesday into Thursday, with the GFS considerably stronger and a little to the northwest of the ECMWF through early Friday, whilst the ensemble means are indicative of a farther east solution. Both the ECMWF and GFS are also indicating a surface low approaching the southeast Panhandle region, with the former being the more impactful scenario. By the end of the week, the GFS and ECMWF indicate a third storm system that may eventually settle across the northern Gulf region by next Saturday. Given the uncertainty among the deterministic and ensemble guidance for this time range, the forecast was based primarily from a GEFS/ECENS compromise for the Friday to Saturday time period. Some of the 12Z ECMWF and less of the GFS was used for early in the week along with the ensemble means. ...Weather/Hazards Highlights... An intense low pressure system is likely to approach the Aleutians by the middle of the week. This storm is expected to produce strong and gusty winds across the Islands and southwest Alaska mainland, along with additional heavy rain and mountain snow across areas that have already received heavy precipitation over the past week. Onshore flow across the southeast Panhandle region is also expected to produce numerous rain/snow showers on top of already saturated grounds. Farther inland across the Interior and the North slope region, a generally benign weather pattern is expected with little in the way of snow and subzero temperatures for much of the Interior and extending north of the Brooks Range. Hamrick Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Mon-Tue, Dec 7-Dec 8. - High significant wave heights for coastal portions of the Alaska Panhandle and mainland Alaska, Mon, Dec 7. 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