Alaska Extended Forecast Discussion National Weather Service College Park MD 720 PM EDT Sat Aug 9 2025 Valid 12Z Wed 13 Aug 2025 - 12Z Sun 17 Aug 2025 ...General Overview... A rather active weather pattern develops across much of western Alaska and the Aleutians going into early to mid week. An amplifying upper trough over the Bering, and two separate surface lows ahead of it, will likely result in heavy rain from the central Aleutians to the western Brooks Range. The southern low crosses the southern mainland to the northern Gulf by Thursday, and the northern low tracks near the Arctic Coast and weakens, with a relatively weak cold front crossing the Interior and North Slope region. A quieter weather pattern should then settle in across most of the state by next weekend. ...Guidance Evaluation/Preferences... Overall, todays 12Z model guidance suite has come into better overall agreement compared to yesterday, even though significant differences still exist for next weekend. A multi-deterministic model blend worked well for the middle of the week, and then the ensemble means were gradually increased to about 60% by next Sunday owing to greater model differences. ...Weather/Hazards Highlights... An incoming surface low from the Bering in combination with a cold front approaching from eastern Siberia will result in an enhanced fetch of moist southerly flow across western mainland Alaska Tuesday into early Wednesday. Moisture flux oriented towards the terrain across this region will lead to heavier rainfall across portions of the Seward Peninsula and extending north to the western Brooks Range, and a heavy rainfall area remains on the WPC hazards graphic for the 12th and 13th where the best model signal is for the heavie.st rainfall. Elsewhere, moderate to locally heavy rainfall will also be possible across portions of south-central Alaska as the moisture plume associated with the triple point low developing over the northern Gulf works its way inland from the Alaska Peninsula to the Prince William Sound, with perhaps 1-2 inches of rainfall for the windward terrain. Snow is likely for the highest mountains of the Brooks and Alaska Ranges. Temperatures should be near to slightly below average by the end of the week into next weekend across much of the mainland, and near average for the most part for the southern coastal areas. Hamrick 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