Alaska Extended Forecast Discussion National Weather Service College Park MD 757 PM EDT Tue Sep 2 2025 Valid 12Z Sat 06 Sep 2025 - 12Z Wed 10 Sep 2025 ...Windy with locally heavy rain across the Aleutians Friday into Saturday followed by a round of widespread moderate rainfall across the Southwest and western Mainland Sunday into Monday... ...Guidance Evaluation/Preferences... The ECMWF yesterday led the way of forecasting a cyclone to track across western Alaska closer to the coast. The GFS and CMC have followed suit with a track in much better agreement with the ECMWF since then. For the next cyclone in its wake, model agreement has further improved since yesterday. The consensus is for the cyclone center to make landfall on the west coast of mainland Alaska early on Day 5 Sunday. Similar to the preceding cyclone, the ECMWF favors a track closer to the west coast while the GFS shows a more southern track toward the southwestern coast. The CMC is in agreement with the ECMWF however. As this cyclone weakens over mainland Alaska Days 6 and 7 (Mon-Tue), there is increasing model agreement for the next cyclone to approach the western Aleutians. Model spread has decreased since yesterday, and there has been a better consensus for a deeper cyclone to impact the Aleutians by Day 7 next Tuesday. The operational ECMWF has flipped to a solution similar to yesterday's GFS with a much stronger cyclone advancing into southern Bering Sea by then. Meanwhile, the GFS has flipped to a weaker solution with a track passing just south of the island chain. A mixed blend of the operational and ensemble means is used to handle this cyclone on today's WPC forecast maps. The WPC forecast package for Alaska was based on 40% from the 12Z GFS and GEFS, 40% from the 12Z ECMWF and 00Z/12Z EC mean, and 20% from the CMC and CMC mean, trending toward a blend mostly from the ensemble means by late in the forecast period. This blend yielded excellent compatibility with yesterday's WPC forecasts. ...Weather/Hazards Highlights... A prevailing storm track from the Aleutians toward western Alaska will continue to bring active weather with frequent rounds of wind and rain across these areas through the forecast period. The heavy rain threat associated with the first cyclone should be quickly easing across the western Brooks Range on Friday, but a period of wet snow can be expected to spread across the eastern section of the Brooks Range as colder air arrives behind the weakening system on Friday. The next cyclone in line appears to be stronger than its predecessor, with the highest threat of gale force winds and moderate to possibly heavy rain to impact western to central Aleutians early on Friday. Models are in agreement with a gradual weakening of the system thereafter, with a slightly lower threat of high winds and heavy rain to impact the eastern Aleutians to the southwestern coastline on Saturday. Nevertheless, windy and rainy conditions are expected to spread further into western Alaska from Sunday into Monday. As the system pushes farther inland, the western portion of the Brooks Range appears to be the target of another round of moderate to locally heavy precipitation early next week. Meanwhile, there is increasing model signal for another relatively deep cyclone to reach the western Aleutians early next week, with its wind and rain possibly spreading into the Alaska Peninsula and the southern coastline by Tuesday night. The southern periphery of the two systems mentioned in the previous paragraph is forecast to bring a couple rounds of moderate to locally heavy rain for the southern coastal sections such as Kodiak Island. There will be little to no rain to speak of farther east across much of the Alaska Panhandle until by late Monday next week when rain ahead of the second cyclone edges into the region. With the prevalence of clouds and rain, cool daytime temperatures are expected across southwestern Alaska. Otherwise, somewhat warmer than normal conditions are expected for the eastern part of the state especially the Panhandle, the North Slope, and portions of the Alaskan Peninsula through early next week. Kong 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