Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 330 PM EST Tue Nov 12 2019 Valid 12Z Sat Nov 16 2019 - 12Z Wed Nov 20 2019 ...Aleutians to Gulf of Alaska Stormy Pattern... ...Guidance/Uncertainty Assessment and Weather Highlights/Threats... Model and ensemble guidance seems fairly well clustered this weekend with the overall pattern evolution and for the most part a number of potentially well organized weather focusing systems. Unsettling mid-upper level troughing will settle from Southwest Alaska northeastward through the Interior/North Slope to the Arctic. Limited moisture and lift will support periods of snow for the region this weekend in gradually easing low level easterly flow. Lead multi-stream low/jet energies are meanwhile slated to work underneath toward southern/southeastern Alaskan from the Gulf of Alaska. These systems pose a maritime threat and the circulations is expected to wrap moisture onshore to sustain some threat of locally heavy precipitation for coastal areas and especially favored terrain this weekend into early next week. A preferred composite solution of the latest models and ensembles seems to offer a reasonable basis for the effects associated with these systems in a pattern with slightly above average overall predictability. The main weather focus will then shift westward toward the Aleutians and southern Bering Sea by early next week and spread steadily toward Southwest and south-central Alaska into next midweek with advance of a series of deep lows. These systems should have closed upper low/trough support and may deepen enough to entrain some deeper lower latitude moisture. Expect a maritime and coastal threat for high winds/waves and heavy precipitation in a pattern with near average predictability. WPC progs used a blend of the GEFS/ECMWF ensemble means amid growing model forecast spread, but manually depened the surface lows given favorable upper support and continuity. 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 precipitation across portions of the Alaska Panhandle and mainland Alaska, Fri-Tue, Nov 15-Nov 19. - High winds across portions of mainland Alaska, Fri-Sat, Nov 15-Nov 16. - High significant wave heights for coastal portions of the Aleutians, Sun-Tue, Nov 17-Nov 19. 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