Extended Forecast Discussion NWS Weather Prediction Center College Park MD 1203 PM EDT Wed Aug 14 2019 Valid 12Z Sat Aug 17 2019 - 12Z Wed Aug 21 2019 ...Overview and Guidance/Predictability Assessment... Models and ensembles agree at larger scales that broad troughing over the northern CONUS becomes more zonal late this weekend as upper ridging rebuilds again near the New Mexico/Texas border. Broad cyclonic flow will persist across southern Canada with an active pattern there. Great inconsistency remains with the development and location of troughs and lows starting Saturday night with the 06Z/00Z GFS bring much more progressive with a trough over the eastern Canadian Prairies that becomes a closed low over Quebec by Monday than the 00Z ECMWF which has slowed over recent runs and features more of a trough than closed low over Quebec which is also seen in the 00Z UKMET/CMC. Another area of differences between the the GFS and ECMWF/UKMET/CMC is with strong shortwave troughs rounding a deep low over the Northwest Territories which results in a low solution farther inland with the GFS than the other models. Therefore lower inclusion of the GFS was made than usual. ...Weather Highlights/Threats... Heavy rain potential along a stalled front near the eastern Gulf coast to the lower Mississippi Valley into Monday. To the north, shortwave passages along a cold front will focus weekend convection from the Upper Midwest/Great Lakes eastward to the Ohio Valley and Northeast/Mid-Atlantic early-mid next week. In this pattern of less troughing and more ridging, temperatures will be above normal in the Southwest/Southern Plains and Midwest to Northeast for Day 3-7 the period. Daily temperature records look limited to the high minimums over the southeast this weekend, expanding to the northeast early next week. Jackson 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