Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 557 PM EST Tue Feb 04 2020 Valid 12Z Sat Feb 08 2020 - 12Z Wed Feb 12 2020 Models/ensembles show general consensus that an upper-level ridge axis across the North Pacific will gradually build northward across Alaska through the extended forecast period. The dominant storm track will initially be across the eastern Aleutians and north into the eastern Bering Sea, but with the ridge building this storm track should gradually shift westward into next week - closer to the Date Line by next week. The 12Z ECMWF/GFS showed relatively good consensus through the first half of the forecast period, with a surface low moving into western mainland Alaska on Sat, and another quickly following it late Sun - each of these producing potentially strong/high winds near the coast, and precipitation spreading as far north as the Interior. Farther east, another relatively weak wave of low pressure should move along a lingering frontal boundary in the Gulf of Alaska Sun night-Mon, bringing a round of precip to the Panhandle/Southeast Alaska. After that - the storm track shifts west, with most guidance showing a relatively deep low pressure system crossing the western Aleutians/Bering Sea Mon night-Wed (potentially a couple waves of low pressure, although the finer scale details remain difficult to resolve given the time range). Strong warm advection ahead of this system should spread additional precipitation across the Aleutians/Alaska Peninsula and into portions of western mainland Alaska. Model differences on track/timing were a bit higher with this system, so increasing emphasis on ECENS/GEFS ensemble means by that time was used to help smooth out some of these differences toward a consensus solution. Given these considerations, a blend of the GFS/ECMWF was used initially on day 4 (Sat), with a gradual trend toward heavier weighting of ensemble means each consecutive day, and a majority ensemble means after day 6 (Mon). Additionally, with the building upper-level ridge, temperatures are forecast to warm to near or above average across much of the state - the North Slope being the significant exception where colder conditions should linger at least through early next week before perhaps some moderation by midweek. Ryan 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: - High winds across portions of mainland Alaska and the Aleutians, Fri-Mon, Feb 7-Feb 10. - Much below normal temperatures across portions of mainland Alaska, Fri-Sat, Feb 7-Feb 8. 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