Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 350 PM EDT Sat Jun 01 2019 Valid 12Z Wed Jun 05 2019 - 12Z Sun Jun 09 2019 Over most areas north of 50N latitude the guidance shows a fairly ill-defined pattern aloft with below average predictability for specific details. Some common ideas prevail for most of the period though, namely general ridging over the Bering Sea/Arctic and a weakness (possibly containing one or more weak upper lows) over the mainland. Corresponding surface features--Bering/Arctic high pressure and mainland troughing--appear more agreeable than details aloft. Some ridging aloft may try to build into the mainland from the southeast by next Sat or Sun. A blend of operational guidance early in the period (00Z ECMWF, 00Z GFS, 00Z CMC, 06Z GFS in order of greater highest to lowest weight) transitioning toward an even weight among models and means (06Z GEFS/00Z ECMWF mean) by day 8 Sun provides a reasonable depiction of agreeable features at the surface and aloft while downplaying the lower confidence details. The one defined system of interest during the period will be a mid-latitude to northern Pacific system. In a broad sense there is better than average model/ensemble clustering. However there is still enough spread by the latter half of the period to provide uncertainty over effects of the northern periphery of the system (moisture and wind) on areas from the eastern Aleutians/Alaska Peninsula to the Panhandle. Thus far ECMWF/ECMWF mean runs have shown better stability versus the GFS/GEFS mean that have trended somewhat northward toward the ECMWF cluster over the past 24-36 hours. Interestingly the new 12Z ECMWF has jumped a bit northward while the 12Z GFS adjusted a little southeast. Stronger trends in the means provide a more coherent signal that the system should maintain its definition through the period. The starting point described above with modest manual adjustment where appropriate yields a good intermediate solution. This would bring potential for some moisture and moderate wind enhancement to reach areas from the Alaska Peninsula through the Gulf of Alaska next weekend. Rausch 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