Alaska Extended Forecast Discussion National Weather Service College Park MD 550 PM EDT Fri May 16 2025 Valid 12Z Tue 20 May 2025 - 12Z Sat 24 May 2025 ...Overview... Alaska will remain largely between anomaly centers next week, with upper ridging focused just south of the Aleutians and weak troughing over the mainland. A changeable and seasonable pattern is expected with no significant hazards expected. ...Guidance Evaluation and Preferences... The pattern will be generally progressive next week but with a trend toward higher amplitude -- ridge/trough couplet over the Bering/Gulf, respectively. As is typical, uncertainty is higher in this quick-moving pattern due to differences in handling the incoming minor shortwaves upstream and through the quasi-zonal flow across the southern Bering/Aleutians early in the period. The 12Z GFS was unlike the ECMWF/Canadian and most ensembles in this regard over northeastern Russia before this medium range period, which resulted in an offset in timing between the larger cluster of solutions. However, by the end of the period, the GFS did align better with consensus in forecasting digging troughing in the Gulf in response to building ridging upstream just west of 180. With the ECMWF showing inconsistency as well in the days 4-6 period with the lead shortwave into the northwestern Gulf, opted to rely on a blend of the 00/12Z ECMWF with the 12Z Canadian and 00Z ECMWF ensemble mean for most of the forecast. This did modify continuity (timing) and progression but the pattern suggests this may be the case for another day or two before things hopefully settle down. ...Weather/Hazards Highlights... Weak troughing over the mainland will promote near to below normal temperatures amidst mostly cloudy skies and widespread showers. More focused rainfall can be expected over the Aleutians with the passing systems and along the northern Gulf Coast as an area of low pressure settles into the region later in the week. Fracasso 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