Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 544 PM EST Thu Nov 14 2019 Valid 12Z Mon Nov 18 2019 - 12Z Fri Nov 22 2019 ...Aleutians to Gulf of Alaska Stormy Pattern... ...Guidance/Uncertainty Assessment and Weather Highlights/Threats... Ensemble model guidance seems fairly well clustered through next week with the overall pattern evolution and for the most part, a number of potentially well-organized weather focusing systems. Unsettling mid-upper level troughing should hover across southwest Alaska towards the North Slope, with limited moisture and lift supporting periods of snow for the region in gradually easing low-level easterly flow. Meanwhile, a leading deep surface low should move from the western Aleutians towards the southern Bering Mon-Wed with a second system following mid to late next week along roughly the same trajectory. Both of these systems pose a maritime threat for high winds/waves, with moisture expected to wrap onshore sustaining some threat of locally heavy precipitation for coastal areas and especially the favored terrain. The WPC blend for today favored mostly deterministic (GFS/ECMWF) models for days 4-5, with increasing ensemble mean support through day 8 amid growing model forecast spread with individual systems. This maintains good continuity with the previous shift as well. Santorelli 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, Tue-Thu, Nov 19-Nov 21. - Heavy snow across portions of mainland Alaska, Tue-Wed, Nov 19-Nov 20. - High significant wave heights for coastal portions of the Aleutians, Mon-Tue, Nov 18-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