Extended Forecast Discussion NWS Weather Prediction Center College Park MD 349 PM EDT Mon Jul 20 2020 Valid 12Z Thu Jul 23 2020 - 12Z Mon Jul 27 2020 ...Overview and Weather/Hazard Highlights... A general CONUS pattern of a persistent trough over the West Coast, a strengthening ridge over the central/southern CONUS and intermittent troughing over the Northeast is expected late this week and into next week. An active jet with several shortwaves/frontal waves traversing the northern tier of the CONUS/southern Canada and a closed high developing over the east-central Great Plains sets up a Ring of Fire type pattern. This setup should bring a multiple rounds of showers and thunderstorms during the medium range for the Northern Plains/Great Lakes with a couple rounds for the Northeast/Mid-Atlantic. On the south side of the high, a broad trough moving west in the Gulf of Mexico will keep the central/western Gulf Coast states wet late this week into the weekend, with scattered to numerous showers and storms. Finally, monsoonal moisture will increase across the Four Corners region by later this week, with diurnal thunderstorms increasing through the weekend between the central U.S. ridge and troughing persists over the West Coast. The building central U.S. ridge/high will support another round of above average temperatures, beginning across the Northern Plains/Midwest Friday/Saturday, where highs are forecast to be 5 to 12 deg F above average. This heat bubble expands east, increasing once again across portions of the Mid-Atlantic Sunday/Monday as well. Troughing along the West Coast will keep max temps 5 to 10 degrees below normal at least through Friday. ...Guidance/Predictability Assessment... Models/ensemble showed improved consensus at larger scales, with minor detail differences increasing through time. This scenario lends well to a heavily deterministic blend (00Z ECMWF/UKMET and 06Z GFS) during days 3-5 (Thursday to Saturday), and gradually increasing emphasis on 00Z ECENS/06Z GEFS ensemble means which are in good agreement during days 6/7 (Sunday/Monday). Overall forecast confidence was slightly above average with the main uncertainty with the strength of the western Gulf trough Days 4/5. 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 Hazards: - Heavy rain across portions of the Southwest, the Central Great Basin, the Central/Southern Rockies, the Plains, the Upper Mississippi Valley, and the Great Lakes, Thu-Mon, Jul 23-Jul 27. - Heavy rain across portions of the Southeast, the Mid-Atlantic, the Lower Mississippi Valley, and the Southern Plains, Thu-Fri, Jul 23-Jul 24. - Flooding occurring or imminent across portions of the Upper Mississippi Valley and the Northern Plains. - Flooding likely across portions of the Central Plains. - Excessive heat across portions of the Central/Northern Plains and the Upper Mississippi Valley, Fri-Sat, Jul 24-Jul 25. - Excessive heat across portions of the Southeast and the Mid-Atlantic, Thu, Jul 23. - Excessive heat across portions of the Southeast and the Mid-Atlantic, Mon, Jul 27. - Much above normal temperatures across portions of the Central/Northern Plains, the Upper Mississippi Valley, and the Great Lakes, Fri-Mon, Jul 24-Jul 27. 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