Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 518 PM EST Thu Dec 24 2020 Valid 12Z Mon Dec 28 2020 - 12Z Fri Jan 01 2021 ...Overview and Guidance/Uncertainty Assessment... Upper troughing in the Bering will translate ESE into the southern Gulf/Northeast Pacific later next week as ridging holds over the Interior/eastern Alaska. After the lead front associated with the deep Bering upper low moves into the Gulf and weakens Tuesday, subsequent systems around the upper low's circulation will skirt along 50-55N. Wavy zonal flow will yield fast-moving and hard-to-time systems Tue-Thu across the North Pacific. Broad blend of solutions offered good continuity from the forecast 24 hrs ago, so no one model was favored explicitly. The GFS appeared a bit suspect over higher latitudes (Beaufort Sea/Arctic Ocean) with its upper pattern but otherwise was plausible. By next Tue-Thu, favored the ensemble means as a best guide with more weight toward the better-defined 00Z ECMWF ensemble mean vs the 12Z GEFS mean, though both were fairly close on track/timing considering the lead time. With a deepening upper low over eastern Asia later next week, a well-defined system may emerge into the western Bering with another downstream making the turn northeastward into the Gulf. A more amplified pattern suggest better predictability going forward. ...Weather/Hazards Highlights... Modest to locally heavy rain/snow is possible over southeastern-facing areas of southern coastal Alaska, especially the Kenai Peninsula, as the occlusion and triple point low push through early in the week. Generally lighter and scattered rain/snow is forecast for Tue-Thu with the systems offshore. By the end of next week, more organized rain/snow will push through the Aleutians and perhaps approach the Panhandle. Temperatures will generally be near to above normal through the period, especially over western areas of the mainland. Fracasso 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 mainland Alaska, Mon-Tue, Dec 28-Dec 29. 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