Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 510 PM EST Thu Mar 04 2021 Valid 12Z Mon Mar 08 2021 - 12Z Fri Mar 12 2021 ...Overview and Guidance/Uncertainty Assessment... The medium range period begins on Monday with a broad upper level ridge axis over east-central Alaska, and a broad upper level gyre over eastern Siberia and the western Bering Sea region. By the end of next week, a broad upper trough will likely exist across the Gulf of Alaska region along with a possible low pressure system, and an upper ridge trying to build back in across the Aleutians and Bering Sea. The 12Z deterministic model guidance is in good overall synoptic scale agreement over the Alaska domain through about Tuesday. Overall model agreement has improved for most of this forecast period compared to yesterday, and the strong low that has been advertised for the middle of the week has trended farther south and slower, although the operational GFS is stronger and closer to the coast, so that will continue to be monitored. The fronts/pressures forecast was primarily derived from a GFS/GFS parallel/ECMWF/EC mean blend, with some of the GEFS mean introduced later in the forecast period. ...Weather/Hazards Highlights... Much of mainland Alaska is expected to have widespread light to moderate snow as moisture flows northward ahead of the strong Bering Sea storm system early next week, especially for the western half of the state where some 6+ inch snowfall totals are possible. Moderate to locally heavy precipitation is likely for the southern coast and adjacent mountain ranges with moisture advecting northward from the Gulf of Alaska through midweek. More widespread impacts are possible if the Gulf low tracks closer to the coast or becomes stronger than currently forecast. Temperatures will likely be near to above average through Wednesday before a return to below average readings to close out the week. Hamrick Hazards: - Heavy precipitation across portions of mainland Alaska, Mon, Mar 8. - High winds across portions of mainland Alaska, Sun-Mon, Mar 7-Mar 8. 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