Alaska Extended Forecast Discussion National Weather Service College Park MD 556 PM EDT Wed Aug 13 2025 Valid 12Z Sun 17 Aug 2025 - 12Z Thu 21 Aug 2025 ...Guidance Evaluation/Preferences... Guidance overall seems reasonably well clustered over medium range time scales, maintaining forecast confidence at above normal levels well into next week. Favor a composite of the latest models for Sunday to Tuesday for best detail. Again opted to increasingly infuse ensemble guidance into the blend onward by next midweek amid slowly growing forecast spread. The blending process inherently tends to maintain best product continuity while mitigating lingering smaller scale flow embedded system errors as consistent with individual predictability. Manual adjustments were also applied to offset inherent system blend weakening as needed. ...Weather/Hazards Highlights... The medium range upper flow pattern over Alaska and vicinity will remain highlighted through well into next week by slow to dislodge closed lows/troughs over the Arctic Ocean and the eastern Gulf of Alaska. A deepened surface low pressure system meandering in the eastern Gulf will keep periodic rain chances over the Southeast Panhandle, with the most appreciable rainfall lingering into early this period with main low proximity and frontal progression as well as with easterly wave energy. Across the North Slope/Brooks Range down into the Interior, shortwaves with some scattered modest rain chances will rotate through the base of a deep low well north of the area over the Arctic Ocean. There is also some upstream flow transition in the offing into next week as an uncertain series of shortwaves and associated surface systems/rain chances work through the Aleutians to the western Gulf into early next week and perhaps with more energy to the western Bering by next midweek that has some potential to eventually bring enhanced rains/winds downstream to the Mainland. Schichtel Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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