Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 651 PM EDT Sat Apr 03 2021 Valid 12Z Wed Apr 07 2021 - 12Z Sun Apr 11 2021 ...A cold pattern for Alaska and stormy offshore waters... ...Guidance/Uncertainty Assessment... Guidance shows an amplified large scale pattern over Alaska at medium range time scales, generally with a cold trough dug over the state and a ridge to the west that is gradually worked into by additional but uncertain upstream trough energies. Significant embedded system differences become increasingly evident over time. Accordingly, the WPC Alaskan product suite was primarily derived from a blend of the 12 UTC GFS/ECMWF, the 12 UTC GEFS/ECMWF ensemble means and the 19 UTC National Blend of Models, but with increasing weight applied to the ensembles over time. Manual adjustments were then applied to the blend to ensure offshore low system strength and circulation consistent with favorable upper support, predictability and to account for any weakening due to the blending process. ...Weather/Hazards Highlights... An Arctic vortex will dig over an unsettled North Slope and Interior next week and significantly cool the region. Digging/phase energies will support recurring cyclogenesis/frontogenesis over the Gulf of Alaska. This will favor adverse maritime conditions and some periods of terrain enhancing precipitation for Southeast Alaska and the Panhandle. The mainland should dry out as frigid high pressure settles in. This would allow below normal temperatures to expand across almost all of Alaska, with the coldest anomalies (as much as 20-30+ below normal) across the Interior. Upstream system and progression entering the Bering Sea by later in the week remains quite uncertain, but should bring unsettled maritime conditions. Enhanced winds and precipitation will also work across the Aleutians and may reach the mainland next weekend. Schichtel 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