Alaska Extended Forecast Discussion National Weather Service College Park MD 727 PM EDT Tue Sep 23 2025 Valid 12Z Sat 27 Sep 2025 - 12Z Wed 01 Oct 2025 ***Unsettled weather pattern continues for southern and southeast Alaska with multiple rounds of rain and mountain snow*** ...General Overview... An amplified shortwave dropping southeastward from eastern Siberia is forecast to cross the southwestern mainland and re- energize the existing Gulf low for the weekend. The next system will likely approach the Aleutians going into Sunday and Monday, and an arctic trough is likely to persist for the northern third of the state as well. Meanwhile, an upper ridge axis likely extends north to the Bering Strait by the middle of next week. ...Guidance Evaluation/Preferences... The 12Z models feature reasonably good agreement on the synoptic scale for Friday into Saturday, although the GFS is a little more amplified with the strong shortwave/closed low near the Alaska Peninsula. It is also farther south with the accompanying surface low and keeps it more offshore. The next low approaching from the Aleutians appears likely to go southeast towards the southern Gulf with generally less in the way of impacts to southern Alaska compared to what is expected in the short range period. By Tuesday, the GFS is stronger with a low south of the Aleutians, whereas the CMC contrasts with that and has more high pressure over the Aleutians, and lower surface pressures over mainland Alaska. By Wednesday, the guidance is hinting at a more organized low pressure system over the Gulf, but big differences in placement are apparent. Overall, the guidance has trended farther south with the Gulf low for the upcoming weekend, and the AIFS trended to the southeast and a little weaker with the low near the Aleutians on Monday. Given the increased uncertainty in the deterministic guidance, more reliance was placed on the ensemble means for this forecast package by early-mid next week, accounting for about 60% of the blend by next Wednesday. ...Weather/Hazards Highlights... The next low pressure system will bring the likelihood for more unsettled weather for southern coastal areas of Alaska and the southeast Panhandle this weekend, bringing periods of rain and mountain snow from the Kenai Peninsula and points eastward. Stronger winds are also expected to develop over the inland passages of southeast Alaska as the southeasterly flow intensifies. Although the rainfall is not expected to be particularly heavy on any given day, the duration of moderate to heavy rainfall across the southeast was enough to warrant an area on the WPC medium range hazards graphic for the 26th and 27th. There is also a third system to watch that may track close to the Aleutians on Monday, and this could be the eventual remnants of what is currently Typhoon Neoguri. In terms of temperatures, colder conditions will be commonplace across most of the mainland, with subfreezing overnight lows widespread across the Interior, and 10s to low 20s near the Brooks Range. The greater Anchorage area may have overnight lows that approach the freezing mark at times, and locations near the Pacific coast in the low-mid 40s. 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