Extended Forecast Discussion NWS Weather Prediction Center College Park MD 249 AM EDT Tue Aug 13 2019 Valid 12Z Fri Aug 16 2019 - 12Z Tue Aug 20 2019 ...Overview and Guidance/Predictability Assessment... A mean upper trough digs into the Northwest/West with uncertain amplitude late week as ridging settles over the Southwest and south-central U.S. This favors some downstream troughing into the East. Northwest U.S. trough energies eject over the northern Rockies/Plains then Midwest/Great Lakes/Northeast through the forecast period, but details remain unclear as models remain highly run to run inconsistent. Accordingly, The WPC medium range product suite was mainly derived from a composite blend of the generally compatable 18 UTC GEFS mean, 12 UTC ECMWF ensemble mean, and National Blend of Models. ...Weather Highlights/Threats... A wavy frontal system sags southward through the eastern and central states later week to stall over the South/Southeast. Widespread showers and thunderstorms including a threat of local cell training/runoff issues will focus over the Southeast/Gulf Coast as deepened moisture pools into the vicinity of the front. There remains a pre-frontal threat of a few record high temperatures. The Southwest will also experience hot temperatures under the upper high/ridge. Northwest/West upper troughing and system/height fall ejections over the Rockies, north-central U.S. then Northeast may provide dynamics and instabilities to support episodes of enhanced thunderstorms/convective clusters with associated local heavy rainfall/runoff threats. Schichtel Additional 3-7 Day Hazards information can be found on the WPC medium range hazards chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation, winter weather outlook probabilities and heat indices are at: https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml