Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 750 PM EDT Thu Sep 17 2020 Valid 12Z Mon Sep 21 2020 - 12Z Fri Sep 25 2020 ...Overview and Guidance/Predictability Assessment... A surface low and its associated cold front will be lifting into the southern Mainland/Southeast Sunday and Monday. Another low will deepen as it drops from the Bering, across the Aleutians into the central Gulf of Alaska. This system is forecast to be well-defined and wrapped up as it tracks toward the Gulf. Heavy precipitation is expected ahead of the front and areas north of the central low pressure Monday and Tuesday, particularly northern portions of the Aleutian Chain and much of the southern coastal areas. The system will advance to the east spreading heavy rain to the panhandle Tuesday through Thursday. Additionally, high winds will be possible during this time from approximately southern portions of Baranof Island to the Dixon Entrance as the front slows and remains in the Gulf. The GFS is favoring a slight southern trend with the low crossing from the Aleutians to the Gulf- the EC and the ensemble means are fairly close to its track, while the CMC persists in being faster than the cluster. The spread increases on Tuesday/Wednesday as the models struggle with the evolution of the system, however convenes by late Wednesday/Thursday. The preferred blend is the 12Z EC/GFS and their means with light weighting of the CMC. ensemble. ...Weather/Threats Highlights... Lingering clouds and showers are possible across parts of the southern Mainland and panhandle as a front moves into Canada early in the period. Increased cloudiness, heavy precipitation and increasing gusty winds will accompany a fairly progressive low pressure system as it tracks across the Bering, the Aleutians and into the Gulf of Alaska next week. Much of the southern coastal areas and the North Slope will have maximum daily temperatures near or below average through at least mid week, while much of the Interior will observe above average temperatures. Campbell 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: - Heavy precipitation across portions of mainland Alaska, Mon-Tue, Sep 21-Sep 22. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Tue-Wed, Sep 22-Sep 23. - Heavy rain across portions of the Alaska Panhandle, Tue-Thu, Sep 22-Sep 24. - High winds across portions of the Alaska Panhandle, Tue-Wed, Sep 22-Sep 23. 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