Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 701 PM EST Wed Nov 17 2021 Valid 12Z Mon Nov 22 2021 - 12Z Fri Nov 26 2021 ...Much below normal temperatures, high winds and heavy precipitation expected across portions of Alaska through the medium range period... ...Overview and Guidance Evaluation/Preferences... The latest guidance once again is gravitating toward a Rex block situation by the middle/end of the extended forecast; where the Ridge over Russia and the adjacent Bering Sea/Arctic Ocean will shift eastward toward northern Alaska. This will allow the trough to shift south/southwest, keeping the surface lows tracking near the the Aleutian Chain and southern coast of the Mainland. However, there is significant spread beyond forecast hour 144 which suggests the models are struggling on the evolution of this pattern by the end of the extended period. A general model blend was utilized up to 144 with increasing weights of the ensemble means beyond to the end of the forecast. Days 7 and 8 have a lower confidence in the specifics with the surface low in the Gulf. ...Weather/Hazard Highlights... Much of Alaska will continue to have colder than seasonal average temperatures, especially across the central and southern regions thanks to surface high pressure becomes established across the state- resulting in numerous locations observing daily readings 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. Precipitation is expected to remain mostly across the Aleutians, along the southern coastal areas and over the Southeast. A majority of the Interior will remain dry in this pattern. There will be periods of moderate to heavy precipitation across the Southeast. 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. 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, Sat-Sun, Nov 20-Nov 21. - High winds across portions of mainland Alaska and the Aleutians, Sat, Nov 20. - High winds across portions of the Alaska Panhandle and mainland Alaska, Sat-Sun, Nov 20-Nov 21, and Wed, Nov 24. - Much below normal temperatures across portions of mainland Alaska, Sat-Tue, Nov 20-Nov 23. 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