205 FXUS02 KWBC 171941 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 341 PM EDT Wed Jun 17 2026 Valid 12Z Sat Jun 20 2026 - 12Z Wed Jun 24 2026 ...Weekend Heavy Rainfall/Flooding and Severe Weather Threat for the Central Plains/Mid-Mississippi/Lower Ohio Valley/Mid-South... ...Pattern Overview and Guidance/Predictability Assessment... Weak mid-level disturbances over the Plains will promote heavy rain and severe thunderstorm threats across portions of the Plains and Midwest this weekend. The GFS is more bullish on the amplitude of these vortices and less progressive than other models, though other guidance did depict some sort of mid-level wave propagating through the southern tier. Thus, a general model blend of the available deterministic and Ai guidance were sufficient enough to capture this evolution through Sunday. Otherwise, quasi-zonal flow will prevail across the rest of the country with some weak troughing pushing through the East by mid- week. An upper ridge begins to develop over the West by next Tuesday, where above average temperatures are likely to return. The usual gradual increase in ensemble mean weighting was applied to the blend between days 5 and 7 next week. Deterministic models struggle to agree on the amplitude of an early-week trough in the Northeast, therefore, the inclusion of the ensemble means as early as day 4, helped mitigate this uncertainty. ...Weather/Hazards Highlights... Weekend Central Plains frontal low genesis and Midwest/Northeast track early next week sets the stage for a stormy weather period. Expect some showers/thunderstorms with energies on the northern periphery over the northern Rockies/Plains and Upper Midwest. Meanwhile, deepening moisture/instability and upper dynamic and frontal system support to the south will lead to threats of heavy rain and flooding with focus across the Central Plains, the Mid- Mississippi/Ohio Valleys states and the Mid-South where the WPC Excessive Rainfall Outlook offers weekend Marginal and Slight Risk areas. SPC also depicts a risk for severe weather over the Central Plains Saturday. Lingering organized convective rainfall focus will work into the East and shift down over a moistened South into early-mid next week with frontal progression and shortwave support. Kebede/Schichtel Additional 3-7 Day Hazard information can be found on the WPC medium range hazards outlook chart at: https://www.wpc.ncep.noaa.gov/threats/threats.php WPC medium range 500mb heights, surface systems, weather grids, quantitative precipitation forecast, excessive rainfall outlook, winter weather outlook probabilities, heat indices and Key Messages 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/#page=ero https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4 https://www.wpc.ncep.noaa.gov/heat_index.shtml https://www.wpc.ncep.noaa.gov/#page=ovw $$