Extended Forecast Discussion NWS Weather Prediction Center College Park MD 300 AM EDT Sat Jun 16 2018 Valid 12Z Tue Jun 19 2018 - 12Z Sat Jun 23 2018 ...Guidance/Predictabillity Assessment... Models and ensembles offer a reasonably similar larger scale pattern evolution over the next week in an active weather pattern, but small-mid scale embedded features still offer quite of bit of forecast spread. Guidance to various degrees has trended to a faster ejection of amplified short range mid-upper level troughing from the West into the n-central U.S. mid-late next week, This occurs as kicker flow emerges upstream from the eastern Pacific into the Northwest. Prefer a solution in between the GFS/ECMWF and their ensembles whose less progression solution than the UKMET and Canadian seems more reasonable given the initial slow and amplified nature of the overall pattern. This includes a hot and humid downstream ridge over the East/Southeast whose northern periphery is eroded by persistent nrn stream cyclonic flow aloft from central Canada to the Northeast U.S. Overall, the WPC medium range product suite was mainly derived from a composite blend of the latest GFS/GEFS and ECMWF/ECMWF ensemble mean along with WPC continuity. This solution maintains good WPC continuity and acts to de-emphasize less predictable smaller scale forecast components whose heavy convective focus remains highly uncertain. ...Weather Highllights/Threats... This will overall lay down a long standing and wavy frontal boundary roughly from the Rockies and central Plains/MS Valley that slowly sinks across the OH Valley and Mid-Atlantic next week. Periods of locally excessive convection will focus in/near this baroclinic zone and in the warm sector aided by early period tropical moisture infux from the Gulf of Mexico. WPC medium range QPF shows heaviest potential over the TX coast with potential tropical wave/disturbance influence and spilling east-southeastward across the central Plains as northward flowing moisture and LLJ energy/instability intersect/train near the wavy front and convectively driven meso-boundaries. Schichtel WPC medium range forecasts of 500 mb heights, surface systems, weather grids, quantitative precipitation, and winter weather outlook probabilities can be found at: http://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif http://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif http://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html http://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml http://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4