Extended Forecast Discussion NWS Weather Prediction Center College Park MD 103 AM EDT Tue Jul 23 2019 Valid 12Z Fri Jul 26 2019 - 12Z Tue Jul 30 2019 ...Weather Highlights/Threats and Guidance/Predictability Assessment... The models indicate a deamplifying eastern US trough this weekend as a mid level ridge builds across Florida. A weakening front in Florida and into the Gulf of Mexico will remain a main focus for convection/rainfall, with return warm/moist advection early next week allowing activity to move north across the lower MS Valley and southeast. The mode persistent feature is the closed anticyclone over the southwest. Expect daily scattered monsoonal convection will work around the ridge over the southern Great Basin/Rockies/High Plains in upper diffluent flow, and pockets of above normal temperatures in the interior CA/OR across NV/ID/AZ. Mid-level impulses and wavy surface fronts will traverse the northern tier states from the Pacific Northwest eastward to the Great Lakes. These will enhance moisture, instability and periods of convection/MCS activity, especially from the n-central U.S. into the Midwest/Great Lakes. Teleconnections from the southwest ridge corresponds to a trough from the Great Lakes to the lower OH Valley, so rainfall probabilities increase in these areas early next week. Downstream from the trough, above normal temperatures redevelop over the northern mid Atlantic to the upper OH Valley and New York/New England early next week. Model forecasts cluster well with ensembles this weekend, with forecast spread then increasing more early next week. WPC medium range surface fronts/pressure/precipitation probability forecasts were primarily derived from a blend of the 12 UTC GFS/ECMWF/UKMET/Canadian models with the 18 UTC GEFS mean and 12 UTC ECMWF ensemble mean. This maintains good continuity. The 18z GFS had a closed low on the southern edge of the guidance distribution near the British Columbia/Alberta border early next week, so the forecast incorporated the 12z GFS run instead. Petersen 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