Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 529 PM EST Fri Nov 20 2020 Valid 12Z Tue Nov 24 2020 - 12Z Sat Nov 28 2020 ...Continued stormy pattern next week... ...Overview and Guidance/Predictability Assessment... Energetic Pacific flow will keep the parade of systems coming into Alaska from the southwest through next week. 12Z models/ensembles were in decent agreement for the first few days of the period, with expected track/depth/timing differences. Trend has been toward the GFS idea from 24 hrs ago with a more defined southern system across the Aleutians Tue into the eastern Bering/Bristol Bay (from along the front attached to the parent low in the NW Bering). With support from all models and ensemble means, depicted this as a modest ~970mb low 12Z Wed. That will move into the Gulf/Panhandle as previously forecast as the pattern remains progressive. Trailing systems have been trending toward being more defined as well, with a potentially quick-hitting but strong system around next Friday. Given that just 24 hrs ago there was little support for more than a weak/modest cold front, opted to rely on a model/ensemble blend and take this astride the Aleutians into Bristol Bay next Sat, with the caveat that this will likely shift in details. Deterministic models later next week (GFS/ECMWF/Canadian) represented plausible solutions but confidence will increase if/when we see persistence in the guidance. ...Weather/Threats Highlights... Each system in the pattern will spread light to moderate precipitation over much of the state except for northern and northeastern areas on the edge of upper ridging. Focus for most of the precipitation will be along western areas Tue/Wed as the lead Bering system wanes, followed by southwestern areas (AKPen/Y-K Delta) as the southern low wraps up in Bristol Bay at the same time. Eastward movement across the Gulf should largely spare Southcentral from significant precipitation and instead bring most of it to the Panhandle with little break. Depending on the details of the system next Fri, heavy precip and windy conditions could again overspread the eastern Aleutians to the AKPen and Y-K Delta region should the forecast unfold as depicted. Temperatures will remain well above normal along northern areas thanks to upper ridging and above normal lower level temperatures, perhaps extending along western areas as well. Southeastern third of the mainland into the Panhandle will see varied temperatures with several degrees of typical late November values. Fracasso Hazards: - Heavy precipitation across portions of mainland Alaska, Wed, Nov 25. - Heavy precipitation across portions of the Alaska Panhandle, Mon, Nov 23 and Thu, Nov 26. - High winds across portions of the Alaska Panhandle and mainland Alaska, Mon-Tue, Nov 23-Nov 24. - High significant wave heights for coastal portions of the Alaska Panhandle and mainland Alaska, Mon, Nov 23. - High significant wave heights for coastal portions of the Alaska Panhandle, Tue, Nov 24. 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