Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 703 PM EDT Tue Apr 27 2021 Valid 12Z Sat May 01 2021 - 12Z Wed May 05 2021 ...Weather Pattern and Model Guidance... The forecast period begins with a closed, elongated upper low over western Alaska, a weakening trough over the Gulf and a large low passing south of the central/western Aleutians. The upper low/trough lingers over the Alaska mainland going into next weekend, followed by potential upper level ridging early next week. Meanwhile, the Aleutian low should continue slowly eastward near 45-50 degrees north and reach the northern Gulf by next Monday, albeit a little weaker by this time. There continues to be spread with the amplitude and clustering of lows associated with the Bering Sea/Gulf of Alaska system. The ECMWF appears to be a tad less progressive and resembles the CMC and UKMET solutions; whereas, the GFS tracks the low further south through much of the extended period. The greatest uncertainty remains across the Bering Sea and eastern Siberia regarding a separate shortwave pivoting around the upper trough over western Alaska, and how that eventually evolves. The preferred blend utilized the 12Z ECMWF/CMC/UKMET/GFS initially with increasing inclusion the ECMWF/GEFS means. ...Sensible Weather... With the influence of an upper-level trough and persistent cloudiness, much of the western Mainland will have cooler temperatures; with near to slightly above normal for portions of the North Slope and the eastern Interior. This pattern will favor precipitation over parts of the southern Mainland and most of the Southeast. There will be two main rounds, with the first round on Friday/Saturday associated with the weakening disturbance from the northern Gulf region and the second will likely affect locations from the Alaska Peninsula to the southeast Panhandle as the next storm system approaches from the Aleutians. Campbell/Hamrick Hazards: - Heavy precipitation across portions of the Alaska Panhandle, Fri, Apr 30. Additional 3-7 Day Hazard information can be found on the WPC medium range hazards 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