344 FXUS02 KWBC 181910 PMDEPD Extended Forecast Discussion NWS Weather Prediction Center College Park MD 310 PM EDT Thu Jun 18 2026 Valid 12Z Sun Jun 21 2026 - 12Z Thu Jun 25 2026 ...Heavy Rainfall/Flooding Threat from the Midwest to portions of the Northeast late this weekend into Monday... ...Building heat for the Southwest... ...Pattern Overview and Guidance/Predictability Assessment... A fairly progressive upper pattern will take shape over the CONUS next week with building upper ridging over the Southwest as they approach their typically hottest time of year. This also favors modest troughing over the northeastern 1/3 of the Lower 48, but heights will trend toward near to slightly above normal through the week, allowing temperatures to moderate. Rainfall will follow along the path of embedded storms within the pattern, primarily over the central Plains/Midwest to the East. A more organized storm Sun-Mon may bring some locally heavier rain to some areas of the central Plains to the Midwest. The models/ensembles were in generally good agreement, but the progressive flow leads to system timing differences that are difficult to pin down beyond a few days. Therefore, a blend of the guidance was utilized though with less to no emphasis on some of the apparent outlier solutions. The 00Z ECMWF offered the best compatibility with the ensembles overall and the NBM was reasonable through the period. ...Weather/Hazards Highlights... Given the risk of heavier rain, we have continued the Slight Risk of excessive rainfall across the Plains/Midwest/lower Great Lakes on Sunday. Some strong to severe thunderstorms can also be expected ahead of the system. The front is forecast to clear the Northeast and the Mid-Atlantic by Tuesday, but the trailing portion of the front is forecast to become stationary across the Southeast into the southern Plains. Lingering moisture in the region may support moderate to locally heavy rain later next week from the Plains eastward ahead of another system exiting the Rockies. Generally near to below normal temperatures appear likely for much of the eastern two-thirds of the Lower 48 through the the middle of the week, with a slight moderation by the end of the week. The highest heat and humidity will be confined to Texas, near the Gulf Coast, Florida, and portions of the southern Mid- Atlantic where HeatRisk values will waver between Moderate and Major. Meanwhile, above normal temperatures (and dry conditions) will prevail across the West with highs gradually climbing further into the 100s-110s in the Desert Southwest. Above normal temperatures will spread from the Northwest into the Great Basin/Rockies by midweek. Fracasso/Kong 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 $$