Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 251 PM EDT Fri May 24 2019 Valid 12Z Tue May 28 2019 - 12Z Sat Jun 01 2019 Deterministic and ensemble model guidance continues to show good agreement on the overall synoptic evolution over Alaska through the medium range period. The upper level pattern favors a blocking ridge in place over mainland Alaska which allows for a meandering main cyclone near the central to eastern Aleutians where it gradually weakens and dissipates. This supports unsettled weather across much of the Aleutians through most of the period, with rounds of locally heavy precipitation along the immediate coast. By the middle of next week the ridge should begin to break down allowing the trough to expand across the mainland and showers to expand northward. Farther inland across central to northern Alaska, mainly showery activity and near normal temperatures are expected, with above normal temperatures possible along the North Slope. A blend of the 00z ECMWF/12z GFS and their respective ensemble means provided a good starting point for today, maintaining good continuity from yesterday's WPC forecasts. Increasing contributions from the ensemble means (and less from the deterministic models) was used later in the period to help mitigate the differences in the details of individual shortwaves traversing the larger-scale trough. Santorelli Hazards: - 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