Alaska Extended Forecast Discussion National Weather Service College Park MD 502 PM EST Tue Nov 18 2025 Valid 12Z Sat 22 Nov 2025 - 12Z Wed 26 Nov 2025 ...Synoptic Overview... On Saturday, broad surface troughing across the state from a dying low will remain in place through much of the period. This is due to the development of a blocking pattern in the upper levels. An omega block will set up across the state by Sunday, which will likely become undercut by its western side low over the Aleutians, forcing the ridging north, thus becoming a rex block. The blocks, regardless of form, will prevent any very strong storms from impacting much of the mainland, which will be under the ridging, or the far weaker Gulf low on the east side of the omega block. Meanwhile all the truly active weather will remain out over the Bering, as strong lows track nearly due north, unable to progress east due to the blocks. Once the pattern transitions to more of a rex block by Tuesday, most of the Pacific storms will track to the east, south of the Alaska Peninsula, thus keeping most of mainland Alaska quiet. ...Guidance Evaluation and Preferences... A 12Z GFS/ 00Z EC blend was used as the predominant deterministic guidance for the forecast through the weekend, transitioning to a primarily GEFS blend through midweek. The 12Z GFS and 00Z EC were best in line with each other compared to the other guidance, especially into the upcoming workweek. This pattern favors the strong Pacific low over the Bering occluding quickly by Monday with perhaps numerous weak triple point lows developing along it across the Alaska Peninsula and south of the Gulf. Meanwhile, much of the other guidance was significantly off from both this solution and the others, or were major outliers, such as the 12Z EC. ...Weather/Hazards Highlights... The primary hazard impacting the state will be across the western and central Aleutians this weekend. As a Pacific low tracks north, it will rapidly deepen. This deepening low will contrast to the broad ridging across the eastern Bering and western mainland, resulting in a rather narrow (100 mile wide or so) corridor of strong southerly flow. Gusts to 55 kt are probable in this area, especially Saturday night. Fortunately the low and its front rapidly weaken beyond that, ending that threat. With the big low staying well out into the western Bering, no hazardous or otherwise noteworthy synoptic scale weather is expected elsewhere through Wednesday. && Wegman 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