Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 630 PM EDT Thu Sep 30 2021 Valid 12Z Mon Oct 04 2021 - 12Z Fri Oct 08 2021 ...Pattern Overview and Guidance/Predictability Assessment... An active weather pattern can be expected during the extended forecast period across the Alaska domain with a large storm system crossing the Bering and then reaching mainland western Alaska. This will be the extratropical version of what is now Typhoon Mindulle, and a trailing low is likely behind this along with a reinforcing cold front. Another low pressure system may affect the Gulf region as a triple point low may develop. Model guidance is initially well clustered with the arriving extratropical low through Tuesday and also with the decaying low over the Gulf region. There is also relatively good agreement with a secondary low and front that will be trailing the initial storm system across the Bering Sea. A 12Z deterministic model blend was incorporated through Tuesday night. Towards the end of the forecast period next Thursday/Friday, the model signal is becoming a bit more clear regarding a potential triple point low forming over the Gulf region, although still uncertainty remains with low placement and magnitude. There are even more substantial differences with a potential third storm over the Aleutians/Bering by next Friday, with the GFS appearing to be a strong outlier, so leaning more towards the ensemble means seems prudent for days 7 and 8. ...Weather/Hazard Highlights... A period of dry weather can be expected for most of the state on Monday before precipitation associated with the Bering Sea storm arrives across western Alaska by Tuesday. The main concern will be strong winds and very rough seas across the Aleutians and extending up the Alaska coast towards Nome. Moderate to heavy snow can be expected for the higher elevations of the Interior by the middle of next week as the moisture surge moves inland. Additional heavy rain and mountain snow is becoming more likely from the Kenai Peninsula to the southeast Panhandle for next Wednesday and Thursday with the potential offshore low development. Temperatures are expected to initially be quite chilly for most of the state through Tuesday before a slight moderating trend ensues ahead of the Bering Sea storm system across the western half of the state. Hamrick Hazards: - High winds across portions of mainland Alaska and the Aleutians, Mon-Tue, Oct 4-Oct 5. - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Wed-Thu, Oct 6-Oct 7. Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook 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