Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 659 PM EST Sat Mar 13 2021 Valid 12Z Wed Mar 17 2021 - 12Z Sun Mar 21 2021 ...Overview and Guidance/Uncertainty Assessment... The latest guidance continues to suggest a blocky pattern early in the period with an upper low over the Gulf, ridge over the Bering Sea, and a trough over eastern Siberia. The deterministic models are in decent synoptic scale agreement through about Thursday. By the second half of the forecast period, there is increasing model spread with respect to the evolution of shortwave energy around 160W and its phasing with northern stream energy. At the surface, a couple waves of low pressure will likely lift toward the southeast coast and southern mainland early in the period, then with some ridging expected to develop aloft for day 6-8 over western mainland Alaska. The WPC blend consisted of the 12Z ECMWF/GFS/UKMET through Thursday, followed by mostly a ECENS/GEFS/ECMWF/GFS blend for days 6 through 8. ...Weather/Hazards Highlights... Aside from possible waves of low pressure brushing or affecting the southeastern coast and Panhandle early on, the rest of the period should be relatively quiet from a sensible weather perspective, especially for most of the mainland. The southeastern Panhandle region has the best potential for organized precipitation for the middle of the week, and the Aleutians will likely have several rounds of rainfall passing through the region. Aside from the North Slope where temperatures are forecast to be slightly above normal, the rest of the region is expected to see near to slightly below normal temperatures during this forecast period. Taylor/Hamrick No significant hazards are expected over Alaska during this forecast period. 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