Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 656 PM EST Mon Nov 15 2021 Valid 12Z Fri Nov 19 2021 - 12Z Tue Nov 23 2021 ...Much below normal temperatures likely across Alaska through the medium range period... ...Overview and Guidance Evaluation/Preferences... The latest suite of guidance continues to have above average predictability with the expansive blocky pattern over Russia and areas west of the Mainland, keeping a mean trough near/south of the Aleutian Chain through the extend period. The degree of clustering among the global guidance through about 00Z 21 November lends to above average confidence on this pattern evolution. However, beyond this time the degree of spread increases. The 12z GFS, ECMWF, and CMC continue to show reasonable agreement with the large scale pattern for a purely deterministic model blend days 4-5. The ensemble means were included for in increasing weights through the end of the forecast period. This model blend helped maintain continuity from the previous issuance. ...Weather/Hazard Highlights... Through the extend period the precipitation will mainly be focused over the southern coastal areas, the Southeast and along the Aleutian Chain. Elsewhere, very cold temperatures and dry conditions will persist. As the surface low moves through the Gulf through Friday there will be periods of moderate to heavy precipitation over the the Panhandle region. This pattern also favors flow funneling through the mountain ranges of southern Alaska; which may lead to strong outflow winds across Southwest Alaska. Wet and unsettled conditioned will return as another system tracks into the Aleutians late in the period, spreading from the Aleutians to locations along the southern coast and enhancing over the Panhandle by next weekend. Much below normal temperatures should prevail across much of Alaska, especially the central and southern regions, through next week as surface high pressure becomes established across the state. The most pronounced anomalies should be over the western to southern part of the state where daytime highs could be as much as 20-30+ degrees below normal. The temperatures are expected to stay cooler than average, although they may moderate as the synoptic flow becomes less amplified. The North Slope will likely remain near, or briefly above seasonal normal through the extended period. Campbell Additional 3-7 Day Hazard Information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php - Heavy precipitation across portions of the Alaska Panhandle, Sun-Mon, Nov 21-Nov 22. - Much below normal temperatures across portions of mainland Alaska, Thu-Mon, Nov 18-Nov 22. - Much below normal temperatures across portions of mainland Alaska, Thu-Fri, 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