Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 641 PM EST Wed Jan 15 2020 Valid 12Z Sun Jan 19 2020 - 12Z Thu Jan 23 2020 ...Overview... Upper-level ridging over the the North Slope and northwest Canada will quickly move north and east allowing for longer period of upper-level troughing to setup over the North Pacific Ocean into the Gulf of Alaska. This pattern will remain mostly in place during the extend period thanks to a fairly progressive North Pacific/Aleutians/Bering stream. This synoptic pattern favors warming across southern Alaska initially along with focused precipitation over the Panhandle and westward to around the eastern part of the Kenai Peninsula with one or more northeastern Pacific/Gulf waves. The Aleutians should see some light precipitation through the weekend, followed by the possible arrival of an organized area of moisture associated with a North Pacific system by mid-week. ...Guidance/Predictability Assessment... Model guidance continues to be in general agreement with a mean trough extending from eastern Siberia to the Gulf of Alaska and multiple lows traversing eastward; however, the timing and latitudinal differences mentioned with the previous forecast package have yet to resolve. A compromise of the 12Z ECWMF/GFS with light weighting of the their ensemble means provided an acceptable solution. This combination also helped maintain a sense of continuity in regards to a compact upper low tracking north-northwest between Siberia and the western mainland that may interact with separate upper low/trough energy that approaches from the west. Another feature of note is fairly strong system in the North Pacific that may bring an increase in clouds and precipitation to portions of the Aleutian Chain by the middle of next week. Again, there continues to be significant spread with the specifics and confidence on the timing and amplitude are at or below average at the time of this issuance. With lower confidence of the evolution by the end of the forecast period, weighting of the ensemble means increased for days 5-7. ...Weather/Hazards Highlights... Warmer temperatures are expected this weekend across much of southern and southeast Alaska, moderately from below normal. A few locations may actually rise to above normal, particularly near the southeast Mainland region. Above normal temperatures will also be in place for the North Slope and surrounding locations this weekend. Periods of scattered to widespread precipitation will likely focus from the eastern Kenai Peninsula to the Panhandle from Sun into next week as one or more waves reach the Gulf; intensity may become moderate to heavy. The Aleutians will see light to isolated moderate precipitation through the weekend into early next week, followed by uncertain coverage/intensity of organized precipitation depending on the track of the system to the south. Campbell 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 - Much below normal temperatures across portions of mainland Alaska, Sat-Mon, Jan 18-Jan 20. - Much below normal temperatures across portions of the Alaska Panhandle, Sat, Jan 18. 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