Extended Forecast Discussion NWS Weather Prediction Center College Park MD 442 PM EDT Fri Jul 26 2019 Valid 12Z Mon Jul 29 2019 - 12Z Fri Aug 2 2019 ...Overview and Guidance/Predictability Assessment... An upper high will meander around the Four Corners region as troughing digs into the eastern states as well as the Pacific Northwest. The models/ensembles largely agree for the first few days of the period (Mon into Wed) and a general model blend sufficed. For mid-later next week, recent GFS runs have been the most progressive of guidance aloft with trough energy ejection from the northeast Pacific inland over Canada and into the U.S. northern tier. The ECMWF and ECMWF ensemble mean have been the least progressive, holding most troughing offshore. WPC continuity has been favoring the less progressive solution, but prior support for from the GEFS, Canadian and UKMET is less now. Opted to blend the 00 UTC ECMWF/ECMWF ensemble mean with the now more progressive 06 UTC GEFS mean to address timing uncertainty and trends. This acts to still maintains good WPC continuity, albeit with a less certain flow pattern at these longer time frames. ...Weather Highlights/Threats... Hot temperatures in the Southwest will moderate as monsoonal moisture increases and clouds/showers/storms expand in coverage. Convective rainfall including some locally heavier downpours/runoff issues will focus along and ahead of the frontal boundaries from the Great Lakes and MS/OH Valley early in the week into the Northeast/Appalachia and then the Mid-Atlantic toward the middle and end of the week. Florida may see an enhanced period of rainfall with a dissipating surface boundary over the central peninsula into early next week. Fracasso/Schichtel Hazards: - Flooding possible across portions of the Upper Mississippi Valley and the Northern Plains. - Flooding occurring or imminent across portions of the Lower Mississippi Valley, the Great Lakes, and the Northern Plains. - Excessive heat across portions of California, Mon, Jul 29. 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