Extended Forecast Discussion NWS Weather Prediction Center College Park MD 423 PM EDT Wed Jul 31 2019 Valid 12Z Sat Aug 03 2019 - 12Z Wed Aug 07 2019 ...Overview and Guidance/Predictability Assessment... Strong upper ridging over southwest Alaska and the northeast Pacific favors troughing along the Pacific Northwest and through the Great Lakes with weakening ridging over the Four Corners region. The model/ensembles mostly agree on the longwave pattern and a blend of the deterministic models sufficed for the weekend period. The 00z ECMWF became an outlier by trying to bring the Northwest trough eastward and was deemed less useful with time after Monday. ...Weather Highlights/Threats... Monsoonal moisture will focus rainfall mostly over New Mexico Saturday then into AZ/UT/CO next week. Leftover MCS (uncertain details) may sink through Arkansas early Saturday as it rounds the ridge. Elsewhere, rainfall will follow the front in the north and largely pop up in the afternoon in the Southeast, perhaps enhanced over eastern Florida into the coastal Carolinas as the tropical wave/related disturbance and stationary front across the region dissipate/weaken. Temperatures will be a bit cooler than average over the central states with higher chances of rainfall and clouds. Milder than average temperatures are expected over the Great Lakes and Northeast ahead of the northern tier system. Elsewhere, temperatures will be within a few degrees of typical early August values during the day and near/above average for overnight mins in much of the West. Roth/Fracasso 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 Hazards: - Heavy rain across portions of the Middle/Lower Mississippi Valley and the Southern Plains, Sat-Sun, Aug 3-Aug 4. - Flooding possible across portions of the Upper Mississippi Valley and the Northern Plains. - Flooding occurring or imminent across portions of the Lower Mississippi Valley and the Northern Plains. 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