Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 621 PM EDT Thu May 12 2022 Valid 12Z Mon May 16 2022 - 12Z Fri May 20 2022 ...Overview and Guidance/Predictability Assessment... The upper flow pattern across Alaska over the next week looks to remain quite amplified/blocky as highlighted by strong ridging over the Bering Sea/Aleutians and an elongated trough over the Mainland connecting closed upper low/troughs centered over the Arctic Ocean and eastern Gulf of Alaska. This should persist into early next week before it may finally begin to weaken and shift slowly eastward as the pattern begins to break down some and become less blocky. Models and ensembles seem in better than average agreement for much of Alaska and vicinity with the overall pattern evolution through medium range time scales. 12 UTC GFS/ECMWF solutions in particular are best clustered with the GEFS/ECMWF ensemble means days 4-8 and a composite blend tends to mitigate smaller scale embedded system differences consistent with predictability. An exception is over the Arctic Ocean where the GFS and ECMWF show more significant surface low depiction differences over time whose detail seems correctly marginalized in the blend. The resultant base forecast along with some manual edits to ensure system consistency surface/aloft maintains good product continuity in a pattern with overall above normal predictability. ...Weather and Hazard Highlights... There are chances for modest precipitation across portions of mainland Alaska into next week as upper disturbances/surface fronts work across the area, but the main threat should remain for any river flooding associated with snow melt and ice jams. Offshore to the south, a well organized upper low/trough and associated surface system lingering over the eastern Gulf of Alaska will favor a periodic focus for light to moderate terrain enhanced precipitation over Southeast Alaska/Panhandle into early-mid next week before the system slips southeastward and loses influence over the region. Overall, a pretty benign precipitation pattern for the state. Temperatures across much of the mainland into at least early next week will remain below normal, with much below normal values in some places, especially parts of northern Alaska as a deeper shortwave drops in through the region. Temperatures may moderate some again around Tuesday-Wednesday, though still below normal. Parts of western Alaska and the Peninsula may finally get above normal though as the Bering Sea ridge slowly works inland next week. Schichtel Hazards: - Flooding possible across portions of mainland Alaska, Sun-Thu, May 15-May 19. 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