Alaska Extended Forecast Discussion National Weather Service College Park MD 625 PM EDT Fri Aug 15 2025 Valid 12Z Tue 19 Aug 2025 - 12Z Sat 23 Aug 2025 ...Guidance Evaluation/Preferences... The latest guidance has a fair handle on the overall pattern maintaining a general blocky pattern with a closed upper low over the Arctic Ocean, a trough over the Guld of Alaska and weak ridging over the Bering/North Pacific Ocean. Shortwaves are expected to traverse the flow under the closed low but there are individual model timing/location differences. The GFS continues to be the most aggressive with dislodging the energies but to a somewhat lesser degree than note with yesterday's cycles. Initially started with the 12 UTC GFS/ECMWF/UKMET/Canadian model then quickly reduced the use of the GFS (eliminating after hour 168) while leaning more toward an EC/Canadian solution. The GEFS mean and EC ensemble were included for the later 2/3 of the extended period since they offer a slower flow transition. ...Weather/Hazards Highlights... The medium range upper flow pattern over Alaska should remain highlighted well into next week by a slow to dislodge closed low/trough over the Arctic Ocean and an eastern Gulf of Alaska closed upper low/trough that resets over the western Gulf into next mid-late week with infusion of system energy associated with current central Pacific invest 99W. This system will first spread unsettled/wet weather over the Aleutians/vicinity early next week. An initially deepened surface low pressure system set to slowly eject from the eastern Gulf early-mid next week will keep periodic rain chances over the Southeast Panhandle and up into eastern SouthCentral, with the most appreciable rainfall lingering into early this period over the southern Panhandle with closest main low proximity and rotating easterly wave energies. Across the North Slope/Brooks Range down into the Interior, shortwaves offer multi-day periodic enhancement of rain and Brooks Range focusing heavier snow chances with rotation through the base of a deep low anchored well north of the area over the Arctic Ocean. There is also with time expected emergence of an upstream flow transition as a less series of shortwaves and associated surface systems/rain chances work northeastward to the Bering Sea that by later next week offers potential to bring enhanced rains/winds downstream into/across the western Mainland. Campbell/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