Alaska Extended Forecast Discussion NWS Weather Prediction Center College Park MD 447 PM EDT Mon May 06 2019 Valid 12Z Fri May 10 2019 - 12Z Tue May 14 2019 The models and ensembles still show a blocking pattern through this week into the weekend 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 Gulf of AK and 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 remains slower than the 00z ECMWF/respective GEFS/ECMWF Ensemble Means/Canadian global model, so the 12z GFS was under weighted 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. The spread of models and ensembles actually increased a bit from yesterday, so a blend of the 00z ECMWF/12z GFS /00 ECMWF Ensemble Mean/06z GEFS Mean/NAEFS Mean/Operational Canadian was used Fri through the weekend as the system moves northeast. By 12z Sun there is potential for another cyclone to develop over the northern Pacific and have potential to reach the Aleutians early next week. The 12z GFS/00z ECMWF had good timing agreement while the Canadian global had an intermediate timing in between the GFS and the faster/further east ECMWF Ensemble Mean. A blend of these solutions was used until better agreement develops. 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. Gale force winds are forecasts over the western Gulf of AK with the Thu night to early Fri cyclone. 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