Alaska Extended Forecast Discussion National Weather Service College Park MD 616 PM EDT Sun Jul 27 2025 Valid 12Z Thu 31 Jul 2025 - 12Z Mon 04 Aug 2025 ...Overview... The main upper flow features to affect Alaska for this forecast period are a slow to dispodge closed low over the Gulf of Alaska, a trough lifting over the Arctic Ocean whose late week exit will allow rebuilding of warm ridging over the Interior/North Slope and a trough into the Aleutians/Bering Sea. The latter has a well organized southern Bering Sea surface low pressure system late week/next weekend whose energies slowly work downstream to the Gulf of Alaska to begin lead closed low ejection into next week. ...Guidance Evaluation/Preferences... Overall, the WPC Alaska medium range forecast suite was primarily derived from a composite of well clustered guidance of the 12 UTC ECMWF/Canadian/UKMET models and ECMWF/Canadian ensemble means in an overall blocky pattern with above normal predictability. The 12 UTC GFS and to a lesser extent the GEFS are less in line with WPC product continuity that at least partially stems from less certain interactions and downstream ejection of system energies ahead of slowly lifting and ejecting West Pacific Typhoon Krosa. ...Weather/Hazards Highlights... Expect only lingering light precipitation across mainland Alaska by late this week in the wake of main shortwave trough passage in a warming pattern with an anticipation of upper ridge rebuilding into next weekend/next week with quite warm summer conditions. To the south, moisture and waves rotating around the northern periphery of a main Gulf of Alaska closed low position well offshore should offer multiple periodic rounds of mainly light to moderate precipitation through the period from Southeast to SouthCentral Alaska inland to the Alaska Range. Uptream, expect appreciable rainfall may gradually overspread the Aleutians later week into next weekend as an emerging low pressure system wraps enhanced moisture and windflow. The main low is forecast to settle into the southern Bering Sea and also offer triple point low translation slowly east along the Aleutians, eventually working into blocky flow into the Gulf of Alaska into next weekend/week. This would act to gradually spread organized rains into the western mainland and into the Alaska Peninsula. 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