Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 532 PM EST Sat Dec 26 2020 Valid 12Z Wed Dec 30 2020 - 12Z Sun Jan 03 2021 ...Deep system in the western Bering later next week... ...Overview and Guidance/Uncertainty Assessment... Noisy/complicated/uncertain pattern to start the period will translate into better-defined flow as a deep system enters the Bering Sea around next Friday. With lingering uncertainty in system placement/timing over the open Pacific, favored a multi-center blend though with limited 12Z GFS influence over the water. Parallel 12Z GFS clustered closer to the ECMWF/Canadian/UKMET south of 50N giving credence to a system farther south of the AKPen 00Z Thu than the op 12Z GFS. Closer to Southcentral, 12Z ECMWF was much drier than the others to start the forecast (seemingly too dry). Models and ensembles have trended decidedly deeper with the Bering system for next Fri-Sat, which fits the pattern of the deep western Pacific upper low moving eastward. Trended deeper with the low, into the 950s mb, but not as low as the operational models as low as the 930s mb. Despite the strong center, trend continues to be progressive again today. Triple point low will move into the Gulf around next Saturday and steadily into the Panhandle thereafter. Subsequent shortwave around the mean Bering circulation could tap another surface cold front to follow in its wake. Trended toward the ensemble means for the Fri-Sun period due to timing spread/uncertainty. ...Weather/Hazards Highlights... Generally lighter and scattered rain/snow is forecast for Tue-Wed along the Aleutians and across Southcentral, with some enhancement via stronger embedded features. Bering system will bring at least a period of more modest rain/snowfall and certainly windy conditions (40kts+) around the center. Triple point could provide more focus for locally heavier rain/snow across at least parts of the AKPen/Southcentral by next weekend. Ensembles show the heaviest amounts over southeastern Kenai. Temperatures will generally be near to above normal through the period, especially over western areas of the mainland. Colder temperatures may filter in by next weekend north of the Alaska Range. Fracasso 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