Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 351 PM EST Wed Nov 30 2022 Valid 12Z Sun Dec 04 2022 - 12Z Thu Dec 08 2022 ...Guidance/Predictability Assessment and Preferences... The guidance, outside the 12z ECMWF, shows good agreement concerning the general flow pattern in and around AK. A large and deep upper level vortex over Siberia broadens eastward with time, eventually enveloping the Bering Sea, Aleutians, and western AK. Detail-wise, even counting out the ECMWF which brings a low much closer to western AK early on, there is lingering uncertainty. Chose the blend similar guidance to account for the detail issues that remained. For the 500 hPa heights, pressures, fronts, and winds, generally used a deterministic heavy blend of the 12z GFS, 12z UKMET, and 12z Canadian early on before including up to 50% of the 12z NAEFS mean/00z ECMWF ensemble means. The QPF used the 19z NBM and, 12z GFS, and 12z Canadian solutions. The remainder of the grids were 19z NBM weighted, as usual. ...Weather/Hazards Highlights... There will be several notable weather hazards to contend with. A strong storm system north of Alaska will be responsible for generating intense winds from north of Nome on north and east along the northern Alaskan coast Saturday. Euro ensemble probabilities continue to show up to a 20-30% chance for wind gusts >50 knots across far northern Alaska, with as much as 70% for >34 knots. As that low exist east, the next strong storm system tracks into the Bering Sea on Dec 4. Hazards associated with this storm system include high winds across the Aleutians on north to the Norton Sound and Seward Peninsula. There are elevated locations along the Seward Peninsula and farther northeast that are favored upslope locations for heavy snow. Eventually, this storm system will deliver heavy precipitation along the Upper Peninsula on Day 4/Saturday into Sunday, then towards Kodiak Island on Day 5/Sunday into Monday. Enough ensemble guidance is in better agreement on heavy precipitation area along the Kenai Peninsula and into the southern Mainland which then shifts into the AK Panhandle with time. Roth/Mullinax Hazards: - Heavy precipitation across portions of mainland Alaska, Sat-Tue, Dec 3-Dec 6. - Heavy snow across portions of mainland Alaska, Sat-Mon, Dec 3-Dec 5. - High winds across portions of mainland Alaska and the Aleutians, Sat-Sun, Dec 3-Dec 4. - High winds across portions of mainland Alaska, Sun-Tue, Dec 4-Dec 6. 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 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