Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 340 PM EDT Tue Jun 25 2019 Valid 12Z Sat Jun 29 2019 - 12Z Wed Jul 03 2019 Model guidance continues to suggest that the northern extent of the upper ridge will breakdown through the medium range period, allowing for portions of the mainland to be influenced by a stronger and more active westerly mid/upper-level flow. Although there is a decent signal for a weakening frontal system crossing the Aleutians and into western portions of the mainland; which the associated shortwave that will knock down the ridge. Variability in regards to timing, strengthen and placement within the guidance keeps much of this forecast with below average confidence. The starting point was primarily a blend of the 06/12Z GFS, 00Z ECWMF/CMC; with increasing weighting of the 00 ECWMF/12Z NAEFS and GEFS means by late in the forecast. The primary difference later in the period revolves around the eventual evolution of this shortwave as it moves east, with the ECMWF continuing to amplify the wave into the Gulf of Alaska by Sun night-Mon and the GFS showing a period of somewhat more zonal flow along the northern periphery of a more elongated upper ridge. Ensemble means suggest something in between these two scenarios may be a possibility, thus the use of majority ensemble means by the latter portion of the forecast period was warranted. This setup would bring an end to the drier conditions seen across much of Alaska recently, with an increase in moisture/showers for much of mainland and Southeast Alaska. Ryan/Campbell 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