Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 611 PM EDT Sun Apr 04 2021 Valid 12Z Thu Apr 08 2021 - 12Z Mon Apr 12 2021 ...A cold pattern for Alaska with maritime storms... ...Guidance/Uncertainty Assessment... Models and ensembles show an amplified large scale pattern into medium range time scales, generally with a cold trough dug over Alaska from the high Arctic and a ridge to the west that is eventually worked into by ample but uncertain trough energies. Differences become increasingly significant over time, but recent runs of the ECMWF/Canadian seem better aligned with ensembles than the GFS. This is evident with both the high Arctic intrusion this week and with system and flow transition/progression from the Bering Sea/Aleutians to the mainland next weekend. Accordingly, the WPC Alaskan product suite was primarily derived from a blend of the 12 UTC ECMWF/Canadian, the 12 UTC GEFS/ECMWF ensemble means and the 19 UTC National Blend of Models. ...Weather/Hazards Highlights... High Arctic troughing will dig over an unsettled North Slope and Interior this week and significantly cool the state. Digging/phasing 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 will 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. Systems entering the Bering Sea later week and next weekend are less certain, but will bring unsettled maritime conditions. Enhanced winds and precipitation will also progress across the Aleutians and are expected to work in earnest into 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