Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1145 AM EDT Mon Jul 22 2019 Valid 12Z Thu Jul 25 2019 - 12Z Mon Jul 29 2019 ...Weather Highlights/Threats and Guidance/Predictability Assessment... A summertime medium range flow pattern will persist over the nation to include a lingering/weak eastern U.S. upper trough downstream of an hot West/Southwest upper ridge. Expect some scattered monsoonal convection will work around the ridge over the southern Great Basin/Rockies/High Plains in upper diffluent flow. A far southward sagged front through the South/Southeast and into the Gulf of Mexico will remain a main focus for heavy convection/rainfall. Activity will be fueled by deeply pooled moisture/instability and runoff issues may be compounded by slow/repeat cell motions. Meanwhile overtop, mid-level impulses and wavy surface fronts will traverse the northern tier states from the Pacific Northwest eastward to the Northeast. These will enhanced local moisture, instability and periods of convection/MCS activity, especially from the n-central U.S. into the Midwest/Great Lakes. However, system timing and local focus are increasingly uncertain over time. Model forecasts cluster well with ensembles Thursday to Saturday, with forecast spread then increasing more ernestly into early next week. Accordingly, WPC medium range surface fronts/pressure and 500mb progs were primarily derived from a composite blend of the 06 UTC GFS and 00 UTC ECMWF/UKMET/Canadian days 3-5, then a blend of the compatable 06 UTC GEFS mean and 00 UTC ECMWF ensemble mean into days 6/7. This maintains good WPC continuity. 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