Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 752 PM EDT Wed Jun 24 2020 Valid 12Z Sun Jun 28 2020 - 12Z Thu Jul 02 2020 ...Guidance/Predictability Assessment... The 12 UTC ECMWF provides a seemingly reasonable solution closest to WPC continuity and near the middle of the model and ensemble forecast envelope Sunday into Monday. In particular for a well organized system reaching the Aleutians in that time frame, the 12 UTC ECMWF solution lies between the more progressive GFS/GEFS and the less progressive UKMET and ECMWF ensemble mean. Opted to base the WPC forecast on a blend of the 12 UTC GEFS/NAEFS/ECMWF ensemble means into days 6-8 (Tue-next Thu) amid quickly growing model forecast spread. Differences among ensemble means with respect to these features were smaller, with also much greater degree of consistency. ...Overview and Weather/Hazard Highlights... Two main low pressure/frontal systems will affect AK early in the extended forecast period, one over the Aleutians, and another over portions of western/northwestern mainland Alaska. A relatively deep low pressure system forecast to cross the central Aleutians into Sun will bring showers and gusty winds. System and energy transfer should spread organized precipitation and unsettled conditions out across the Gulf of Alaska and inland into the southern tier of AK early next week. Farther north, low pressure north of Siberia will accompany a frontal boundary across the Bering Strait and into western mainland Alaska Sat-Mon. This system is expected to produce areas of heavy rain and some mountain snow across portions of northwest mainland Alaska, with the potential for high winds across areas close to the Bering coast over the weekend. While widespread precipitation across mainland Alaska should gradually subside toward the middle of next week, persistent broad cyclonic flow will result in continued unsettled conditions, with persistent clouds and precipitation especially across mountain ranges. Schichtel 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 Hazards: - Heavy rain across portions of western mainland Alaska, Sat-Sun, Jun 27-Jun 28. - High winds across portions of western coastal Alaska, Sat, Jun 27. 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