Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 729 PM EDT Fri Oct 21 2022 Valid 12Z Tue Oct 25 2022 - 12Z Sat Oct 29 2022 ...A Bering Sea low will bring a threat of high winds and waves to the Aleutians early to middle of next week with locally heavy snow possible for inland western Alaska midweek... ...Heavy mountain snows and coastal rain threat across the Alaska Panhandle into the southern coastal section late next week... ...Overview and Guidance/Predictability Assessment and Weather/Hazards Highlights... The extended period will begin with a deepening cyclone entering the western portion of the Bering Sea. Latest model guidance has come into closer agreement on the placement of the cyclone center compared with yesterday, but with the GFS/GEFS still tends to be slower as the cyclone moves into the central portion of the Bering Sea Tuesday morning. The cyclone center is forecast to move onshore into southwestern Alaska by Wednesday morning, given very good agreement from both the ensemble means and deterministic guidance (cyclone center position is slightly faster than yesterday's forecast). The system is expected to spread high winds and waves across the Aleutians into southwestern Alaska especially on the back side of the system where very gusty winds can be expected to impact the Alaska Peninsula on Wednesday. Precipitation amounts across the Aleutians are not expected to be excessive. However, deep south to southwesterly flow from the Pacific overrunning trapped inland cold air is forecast to bring a threat of locally heavy snow across the inland sections of southwestern Alaska late Tuesday into Wednesday. Toward the end of next week, ensemble means show decent agreement on the formation of a new center over the Gulf of Alaska and then become the main cyclone center. Heavy precipitation is possible late next week as this system edges closer to the southern coast while moving toward the Panhandle. The ECMWF and CMC tend to be slightly faster with this system compared with the GFS/GEFS. The next system of concern is forecast to move into the Bering Sea/Aleutians late next week into the weekend. There is quite a bit of model spread on its track and intensity, as well as the degree of phasing between the northern and southern stream. The suite of Alaska products was based on 40% 12Z ECMWF/00Z/12Z EC mean, 40% from the 12Z GFS/GEFS, and 20% from the 12Z CMC/CMC mean, transitioning to mostly a comprise of the ensemble means by Day 8. This blend maintains good continuity with yesterday's forecast package. Kong Hazards: - Heavy precipitation across portions of the Alaska Panhandle and mainland Alaska, Thu-Fri, Oct 27-Oct 28. - High winds across portions of mainland Alaska and the Aleutians, Mon-Wed, Oct 24-Oct 26. 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