Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 758 PM EDT Mon Oct 3 2022 Valid 12Z Fri Oct 7 2022 - 12Z Tue Oct 11 2022 ...Synoptic Overview... The extended forecast period begins on Friday with an upper level ridge axis centered across the south-central portion of the state with above normal temperatures across much of the central and eastern portions of the state. A major storm system brushes past the northwestern coast, with the core of the storm expected to pass well to the northwest of the state as it lifts northward across the Arctic. The trailing cold front is forecast to result in a cooling trend going into the weekend and continuing into early next week, and a deep surge of moisture with heavy coastal precipitation can be expected for parts of the southern coast this weekend. ...Guidance/Predictability Assessment... The 12Z model guidance suite depicts good overall synoptic scale agreement across the Alaska domain late in the week. The CMC and ECMWF indicate a stronger trough developing over the northern Gulf by late Saturday compared to the GFS. By early next week, model differences are substantial with a second trough evolution across the Aleutians and also with shortwave disturbances across the Arctic. Overall, a multi-deterministic model blend suffices as a starting point through Saturday, and then gradually increase the ensemble means going into early next week to account for greater forecast uncertainty. ...Weather/Hazards Highlights... The main weather story going into next weekend will be the increasing rain and mountain snow prospects for the southern coastal areas of Alaska and western portions of the southeast Panhandle region, where several inches of liquid equivalent is likely for the topographically favored terrain, as moisture from the Gulf flows northward ahead of a developing surface low near the Kenai Peninsula. More rain is probable for parts of the Aleutians Sunday and next Monday as the next storm system develops in this region. Farther north across the Interior, isolated to scattered showers are likely ahead of the cold front, and snow for the Brooks Range as temperatures return to more seasonal levels. Most locations should see temperatures dropping about 10-15 degrees over the course of the forecast period. Hamrick Hazards: - Heavy precipitation across portions of southern mainland Alaska, Thu-Sat, Oct 6-Oct 8. - Heavy precipitation across portions of the Alaska Panhandle and southern mainland Alaska, Fri-Mon, Oct 7-Oct 10. - High winds across portions of western mainland Alaska, Thu-Fri, 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