Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 423 PM EDT Wed Oct 09 2019 Valid 12Z Sun Oct 13 2019 - 12Z Thu Oct 17 2019 Relatively benign weather is expected to start out the medium-range period in Alaska on Sunday before a deep cyclone, the extratropical transformation of super typhoon Hagibis, moves across the Aleutians by Monday. The model guidance today indicates a higher degree of uncertainty regarding the track of the cyclone through the Aleutians early next week. The ECMWF is now taking the cyclone more on a easterly track along the Aleutians on Monday in pretty good agreement with the GFS and GEFS track. However, this easterly track is contrary to the 00Z EC mean which takes the cyclone into the Bering Sea. In addition, the 00Z Canadian mean also takes Hagibis on a track into the Bering Sea. Thus, the decision was to use a blend of the 00Z EC mean with the 00Z NAEFS for Days 6, 7 and 8. This yielded a cyclone track that was fairly close to continuity. For Days 4 and 5, a general compromise of the 00Z EC mean, 06Z GEFS mean, the 12Z GFS and the 00Z ECMWF was used. High winds and significant waves along with heavy rain can be expected with the arrival of the extratropical cyclone/Hagibis across the Aleutians on Monday. Meanwhile, another occluded cyclone is forecast to edge closer to the south coast of Alaska and the Alaska Panhandle with gusty winds and periods of heavy precipitation possibly lasting into Wednesday. Uncertainty increases as to whether the circulation of Hagibis will eventually merge with this occluded cyclone. However, the trend is for the stormy conditions over the Aleutians to slowly subside during the middle of the week. Kong 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 Alaska Hazards... - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Mon-Wed, Oct 14-Oct 16. - High winds across portions of the Aleutians, Sun-Tue, Oct 13-Oct 15. - Significant wave heights for coastal portions of the Aleutians, Mon-Wed, Oct 14-Oct 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