Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 235 PM EST Sat Nov 09 2019 Valid 12Z Wed Nov 13 2019 - 12Z Sun Nov 17 2019 Models show relatively good consensus that a deep surface low should pass south of the Alaska Peninsula Wed-Thu as it heads toward the Gulf of Alaska. Timing and some remaining detail differences among deterministic and ensemble solutions make for moderate confidence. Incorporated a blend of the latest deterministic guidance (ECMWF/CMC/GFS) into the forecast for days 4-5 (Wed-Thu). Placed particular emphasis on the ECMWF solution during the early extended time frame as its solution seemed very well-centered within the model/ensemble spread. This low pressure system could produce a variety of impacts, including the potential for strong winds and significant waves along the coast - although given a trend toward a more northeastward track into the Gulf while the low is deepest, these impacts could be somewhat limited. As this system weakens near the mainland Alaska coast by Fri, the upper-level energy, along with additional arctic shortwave energy arriving from the north, are forecast to linger across western mainland Alaska or the eastern Bering Sea through late next week. Models differ on the precise interaction between these features, but a number of solutions continue to indicate development of an upper low, while others depict a more disorganized scenario. South of this upper low, a stream of small scale but quick moving shortwaves are expected to cross near the Aleutians and toward the Gulf of Alaska. Spread increases through time, but some consensus was noted among ensemble means that another low pressure system should approach southern mainland Alaska by next Fri night or Sat, associated with one of the more significant aforementioned shortwaves, with yet another crossing the Aleutians Sat-Sun. Given gradually increasing spread, a trend to heavier weighting of ECENS/NAEFS ensemble means was shown during days 6-8 (Fri-Sun). Ryan 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