267 FXUS01 KWBC 201908 PMDSPD Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 307 PM EDT Sat Jun 20 2026 Valid 00Z Sun Jun 21 2026 - 00Z Tue Jun 23 2026 ...Impactful flash floods and severe storms expected over the Plains and Midwest today and tomorrow; locally significant flash flooding also remains possible today across the Southeast and Gulf Coast... ...Widespread thunderstorms with a flash flood threat expected across the Northeast, Ohio/Tennessee/Lower Mississippi Valleys, and into the southern Plains Monday... ...Conditions remain uncomfortably hot across the Southeast with stifling humidity in place while a pair of cold fronts brings mild conditions in the 70s to the northern tier of the central/eastern U.S.... An expansive storm system will bring widespread storms with a threat for flash flooding and severe weather to much of the central to eastern U.S. through the weekend and into early next week. An upper-wave has led to a deepening surface low in the lee of the Rockies today (Saturday). Increasing southerly flow with an upper-ridge just to the east has primed a very moist, unstable airmass expected to lead to widespread storm development across the central Plains this afternoon. The Storm Prediction Center maintains a Slight Risk of severe weather (level 2/5) for the threat of large hail, damaging winds, and a few tornadoes. As the evening progresses, robust thunderstorms are expected to grow-upscale ahead of increased forcing from an incoming cold front, forming a line of storms progressing eastward through the overnight hours. There is a more focused Enhanced Risk (level 3/5) where these more concentrated, intense storms will bring the risk of very large hail and more widespread, significant damaging winds from northeastern Colorado into southern Nebraska and northern Kansas. In addition, plentiful moisture will favor very heavy downpours, and the expanding coverage of storms with the organized system as it progresses east will bring long duration heavy rainfall. A Moderate Risk (level 3/4) of Excessive Rainfall extends from southeastern Nebraska/northeastern Kansas into northwestern Missouri where scattered to widespread flash flooding is expected. A broader Slight Risk is in place across the central Plains into the Middle/Lower Missouri Valley for more scattered instances of flash flooding. These storms are forecast to continue into the day Sunday into the Middle Mississippi and Lower Ohio Valleys. Another round of storms is expected ahead of the approaching cold front back through the Missouri Valley and adjacent central Plains as the atmosphere destabilizes following the overnight storms. Scattered to widespread flash flooding will remain a threat with another Moderate Risk of Excessive Rainfall in place. Some storms may also be severe, and the SPC has a Slight Risk ahead of the front covering these same regions as well as westward towards the central High Plains as post-frontal upslope flow sets up. Large hail, damaging winds, and a few tornadoes will all remain threats. The low pressure system will continue eastward through the Ohio Valley into the Northeast on Monday with the trailing cold front extending southwestward through the Ohio/Tennessee/Lower Mississippi Valleys and into the southern Plains. This will lead to another round of scattered to widespread storms along the length of the front. An expansive Slight Risk of Excessive Rainfall extends along this front to cover the threat for more heavy downpours and scattered instances of flash flooding. Deep Gulf moisture ahead of a lingering frontal boundary north of the Gulf Coast will continue to lead to scattered to widespread heavy rain-producing thunderstorms through this evening with a threat for scattered, locally significant flash flooding as a Slight Risk of Excessive Rainfall remains in place. Back to the northwest, the energetic flow will bring another upper-wave through the Great Basin/northern Rockies today and into the northern Plains Sunday, bringing a chance for scattered thunderstorms. A more concentrated focus of storms along a frontal boundary across South Dakota Sunday will lead to some locally heavier rainfall and scattered flash flooding, with a Slight Risk of Excessive Rainfall in place. This frontal system will progress slowly eastward through Monday with another round of thunderstorms forecast for the northern Plains and into the Upper Midwest. Elsewhere, a backdoor cold front sagging southwestward into New England will bring some thunderstorms to the region Sunday. The upper-wave passing through the Interior West will also lead to some gustier winds across the region, with very low humidity and mostly dry thunderstorm chances prompting a fire weather threat. The SPC has outlooked a Critical Risk for fire weather (level 2/3) over the eastern Great Basin/Four Corners with a more expansive Elevated Risk (level 1/3) more broadly across much of the region. Despite generally near-average highs in the upper 80s to mid-90s across the Southeast to Southern Plains, conditions will remain uncomfortably hot through the next couple days with stiffing humidity present. Heat Advisories cover portions of the reason as heat indices will rise well into the 100s for many. The southern High Plains will also remain hot as temperatures soar into the 100s. Meanwhile, frontal passages this weekend will bring very mild, below to well below average highs to the northern/central Plains, Midwest, and Northeast through the next few days. Highs in the 70s will be common. A mostly near average to just above average weekend continues across much of the western U.S. with highs in the 80s. Conditions will trend hotter into early next week, with highs rising into the 90s. Coastal regions will remain cooler and in the 60s and 70s while the Desert Southwest will see highs in the 100s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php $$