Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 256 PM EDT Sat Jul 13 2019 Valid 12Z Wed Jul 17 2019 - 12Z Sun Jul 21 2019 One upper low will wobble around the Arctic Ocean as another slowly exits the Gulf through the Panhandle. This leaves much of the interior in weak ridging aloft that will be replaced by incoming troughing on the south side of the Arctic upper low late next week. The models/ensembles show good agreement in the northern areas but less agreement over the Pacific. The recent GFS runs were much stronger with a surface low pressure along a baroclinic zone to the north of an upper and sfc high in the mid-latitudes (between Alaska and Hawai'i) as the ensembles generally keep the boundary flat. The flatter scenario is preferred given the setup with seemingly little room to develop so robustly. The 00Z ECMWF was closest to the ensemble consensus and was used to add detail to the forecast with the 00Z GEFS mean and 00Z ECMWF ensemble mean to smooth out some timing differences. Farther north, the 00Z ECMWF may be too aggressive with height falls next weekend with the incoming trough into northwestern Alaska. Blend with the means tempered that in the blend but building ridging into the Bering next weekend could support something like the ECMWF (at least 10-20% of the ensembles were at least as aggressive as the ECMWF). Scattered showers and a few thunderstorms will be possible through much of the forecast period, particularly across the interior and over the higher terrain along the wavy boundary. Coverage north of 65N will increase as the upper trough moves through. Cooler than average temperatures are expected to the north. Upper low and onshore flow will keep the rain chances high over the Panhandle with near to below average temperatures. Fracasso 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