Alaska Extended Forecast Discussion National Weather Service College Park MD 613 PM EDT Tue Aug 12 2025 Valid 12Z Sat 16 Aug 2025 - 12Z Wed 20 Aug 2025 ...Guidance Evaluation/Preferences... Guidance overall seems reasonably well clustered over medium range time scales, bolstering forecast confidence to above normal levels. Favor a composite of the latest models for Saturday to Monday. Opted to increasingly infuse ensemble guidance into the blend onward into 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. However, the 12 UTC ECMWF and ECMWF ensembles were not available for this product due to transmission delay issues. ...Weather/Hazards Highlights... The upcoming medium range upper flow pattern over Alaska and vicinity will be highlighted by the weekend and into next week by ridges over the Bering Sea and western Canada and slow to dislodge closed lows/troughs over the Arctic Ocean and also the eastern Gulf of Alaska. Surface low pressure systems meandering in the Gulf will keep periodic shower chances along the vunerable Panhandle given the ongoing GLOF, with the most appreciable rainfall lingering this weekend 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 over the Arctic. There is also some upstream flow transition in the offing into next week as an uncertain series of shortwaves and associated surface systems may move into the Aleutians and Bering Sea that have growing potential to bring enhanced rains/winds toward the Mainland into late period. 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