Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 602 PM EST Wed Jan 22 2020 Valid 12Z Sun Jan 26 2020 - 12Z Thu Jan 30 2020 ...Well below average temperatures for most of mainland Alaska... The guidance continues to offer good consensus that an upper level ridge will build northward over the Bering Sea Saturday onward, while an upper level trough anchors itself over the Mainland. Forecast confidence is high that the implication for much of mainland Alaska will be strong surface high pressure intensifying near the Bering Strait, as increasingly cold conditions settle over most of the state. Both maximum and minimum temperatures could be near or exceeding 20 degrees F below normal, especially across the Interior, southwestern Alaska, and the northern Alaskan Peninsula. An active North Pacific jet will send various shortwaves/surface lows across the North Pacific into the Gulf of Alaska, which should act to reinforce a closed upper low lingering somewhere near the southern mainland, or northern Gulf. This setup would keep Southeast Alaska with relatively high precipitation chances through much of the period. Chilly temperatures would support snow, not only in the higher elevations, but also working its way into parts of southern Alaska, and the northern Panhandle. While models agree on the overall larger scale pattern, they continue to struggle with the evolution and progression of the series of surface lows entering the Gulf and how they interact with the larger scale trough over Alaska. Accordingly, the specifics of this aspect of the forecast remains more chaotic with below average predictability. As a result, the WPC progs utilized the agreeable 12z GFS/ECMWF with the ensemble means for days 4-5, increasing weighting of the means beyond that time. 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: - Much below normal temperatures across portions of mainland Alaska, Sat-Wed, Jan 25-Jan 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