Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 407 PM EDT Wed Jun 12 2019 Valid 12Z Sun Jun 16 2019 - 12Z Thu Jun 20 2019 Models have converged toward a somewhat faster progression of the upper low across the Gulf of Alaska days 4-6 (Sun-Tue), and this trend was reflected in the latest WPC forecast. Farther north, models have struggled with the timing/amplitude of arctic shortwave energy expected to dive south across northwestern Alaska Mon-Tue, but a blend of solutions should resolve these differences favorably. Deterministic solutions begin to diverge on the details of the forecast from Tue onward, but ensemble means suggest that a broad upper-level mean trough should remain in place from near/south of the Aleutians east into Southeast Alaska and western Canada, with the flow farther north reliant on a complex interaction between westerlies off the Bering Sea/Siberia and easterlies south of a ridge across the Arctic Ocean, the details of which are elusive at this point in time. Given these considerations, the forecast was initially based on a multi-model deterministic blend (00Z ECMWF/CMC/12Z GFS) during days 4-5, with a shift to majority ensemble mean weighting from day 6 onward, and most weight placed toward the more consistent ECENS mean. Ryan 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 No significant hazards are expected over Alaska during this forecast period. 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