Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 309 PM EDT Sun May 05 2019 Valid 12Z Thu May 09 2019 - 12Z Mon May 13 2019 The models and ensembles still show a blocking pattern through this week with a high amplitude Bering Sea trough extending across the Aleutians into the north Pacific and resultant high amplitude ridge across the northeast Pacific and southeast Alaska. Towards the end of next week, the models start to diverge with the timing and placement of vortices rotating around the Bering Sea trough and resultant placement of lows in the Bering/northern Pacific and adjacent southwestern AK. The 00z ECMWF/00z ECMWF Ensemble Mean/06z GEFS Mean show a cyclone developing over the northeast Pacific Thu that then moves north onshore later Fri to early Sat. The 12z GFS lagged several hours behind the 06z GFS/00z ECMWF/respective GEFS/ECMWF Ensemble Means, so the 12z GFS was not included in the blend, with the majority cluster preferred. The next area of interest would be a wave developing over the northern Pacific around 12z Fri south of the Aleutians. There was sufficient clustering on the location among the 00z ECMWF/yesterday's 12z GFS /00 ECMWF Ensemble Mean/06z GEFS Mean/NAEFS Mean to use a blend of these solutions Fri and Sat as the system moves northeast. By 12z Sun there is potential for this cyclone to be as far north as either the upper Aleutians and/or Kodiak Island. At 12z Sun the 00 ECMWF Ensemble Mean and 00z NAEFS Mean/06z GEFS Mean cluster west of the operational ECMWF low pressure center location. Temperatures will be warmer than normal over southeast AK through most of the week due to the strong upper ridge and corresponding warm temperatures that remain well above normal. Precipitation will focus over the southern coastal areas Thu-Fri, with low pressure moving onshore fostering showers moving inland. Locally heavy rain may be possible in upslope locations. Petersen Bullet points from the WPC Days 3-7 Hazards chart can be found 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