Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 359 PM EDT Wed Sep 11 2019 Valid 12Z Sun Sep 15 2019 - 12Z Thu Sep 19 2019 Upper troughing is forecast to settle into central/interior Alaska due to an incoming Bering system and an Arctic upper low dropping southward early next week. This shuffling will work in tandem with deepening troughing over the Sakhalin Oblast (north of Hokkaido) and ridging near the Dateline in the mid-latitudes. Blend of the recent GFS/ECMWF guidance (deterministic and ensemble data) offered a good starting point to the forecast. 12Z GFS was deeper than nearly all ensemble members with the Bering surface low late Sunday (as were earlier runs) but a blend with the ECMWF and ensembles tempered that to a more modest 992mb low. Attendant frontal boundary will likely slow and stall along 50N as a surface wave develops and deepens as northern stream troughing rotates into across the AKPen. This may take that low into the Gulf by next Wed/Thu. Pattern will be fairly wet for southwestern/western areas through Southcentral as the front comes through then into the Panhandle with westerly flow. Multi-day rainfall totals may exceed several inches (4-5") from eastern Kenai to Yakutat into the Panhandle with less rainfall farther inland. However, inland rainfall around the Alaska Range will be more anomalous relative to climatology vs the normally wetter coastline. 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 - Heavy rain across portions of mainland Alaska, Sun-Mon, Sep 15-Sep 16. 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