Alaska Extended Forecast Discussion National Weather Service College Park MD 630 PM EDT Mon Aug 11 2025 Valid 12Z Fri 15 Aug 2025 - 12Z Tue 19 Aug 2025 ...General Overview... The pattern over Alaska should be quiet and stagnant by late week and especially next weekend with blocky and amplified ridges over the Bering Sea and central Canada much of the period. Low pressure meandering in the Gulf will keep shower chances along the Panhandle most days, with the most appreciable rainfall expected Thursday- Friday as a frontal system weakens in the region. Across northern Alaska, weak shortwaves will rotate through the base of a deep low over the Arctic but otherwise ridging will build across the central Mainland. Weak shortwaves may move through the Aleutians atop strong high pressure. ...Guidance Evaluation/Preferences... The current model and ensemble guidance continues to show above average agreement on the large scale blocky and slow moving pattern over Alaska during the extended range. There are some differences in the details of individual weak shortwaves, as they ride the top of a strong ridge over the north Pacific. The 12z GFS was a notable outlier being faster with an initial shortwave and more aggressive with a late period shortwave moving into the Bering. Uncertainty in the details really becomes apparent later in the period, but the guidance at least shows agreement on the large scale. The WPC forecast today used a non-GFS through about the first half of the period, increasing to about 60-70 percent ensemble means days 7 and 8 to help smooth out the smaller scale differences. ...Weather/Hazards Highlights... Rainfall will progress west to east over the Mainland to Southern Coast area associated with upper troughing moving through the state. Moderate rain may be possible along the favored terrain. Conditions should mostly dry out by Friday and into the weekend, but some showers are possible as weak shortwaves rotate through northern Alaska. To the South, rainfall across the Panhandle will gradually become more widely scattered in nature by the weekend and into early next week. Showers may accompany weak shortwaves through the Aleutians but much of central to southern Alaska could be dry. Temperature wise, below average temperatures in the beginning of the period will moderate to near or above normal by the end of the period across much of the state as upper ridging builds. Santorelli 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