Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 500 PM EST Fri Dec 18 2020 Valid 12Z Tue Dec 22 2020 - 12Z Sat Dec 26 2020 ...Guidance and Uncertainty Assessment... Upper troughing across the Aleutians and the Bering Sea on Tuesday will extend southeastward by late next week across the Gulf region, and upper ridging across western Canada will gradually be shunted eastward. The models and ensembles generally agree on this, but vary on the details for much of the period. The 12Z guidance was close enough on the synoptic scale such that a blended solution worked out well along with the ensemble means. More noteworthy differences were noted with the 12Z CMC across the North Pacific, so it was considered less during this forecast period. Perhaps surprisingly, there is better model agreement with a strong storm system that will be on the horizon by the end of the forecast period next weekend. ...Weather/Hazards Highlights... Areas along the southern coast and to the Panhandle could have moderate to perhaps locally heavy precipitation early in the week as the frontal system and developing triple point low move across the Gulf of Alaska region. Several inches of QPF snow are likely over the multi-day period, focused mainly over the southeastern Kenai peninsula. Lighter precipitation is likely over the Aleutians and southwestern areas of the state under the upper low. Temperatures are forecast to moderate for the middle and end of the week as southerly flow overspreads the area, eventually leading to readings above average for many areas. Hamrick Hazards: - Heavy precipitation across the Alaska Peninsula into southern Alaska, Mon-Wed, Dec 21-Dec 23. - Heavy precipitation across portions of the Alaska Panhandle into southern Alaska, Wed, Dec 23. - High winds across the Alaska Peninsula into southern Alaska, Mon-Tue, Dec 21-Dec 22. - Much below normal temperatures across much of the lower elevations of eastern Alaska, Mon-Tue, Dec 21-Dec 22. 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 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