FOUS30 KWBC 080300 QPFERD Excessive Rainfall Discussion NWS Weather Prediction Center College Park MD 1100 PM EDT Sun Jun 7 2026 Day 1 Valid 0247Z Mon Jun 08 2026 - 12Z Mon Jun 08 2026 ...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE OZARKS... 03Z Update... A special update was issued to introduce a targeted Moderate Risk area for portions of the Ozarks that are likely to be impacted by very heavy rainfall within training/backbuilding storms late tonight into early Monday morning. Hi-res CAMs have been trending upwards with rainfall totals over this region, now indicating amounts up to 5-8 inches with rainfall rates exceeding 2 inches per hour. Areas within the Moderate Risk area are likely to be impacted by flash flooding, especially near steep terrain. Dolan 01Z Update... The Moderate Risk was removed from northern Alabama with this update. Convection continues to fire across portions of northern Alabama, but is now south of the area inundated by very heavy rains earlier in the day. The current storms south of the region have mostly shown an easterly trajectory, while convective inhibition to the north is likely to hamper the redevelopment of heavy rainfall rates across the areas most severely impacted earlier. The ongoing convection is expected to gradually wane with the loss of daytime heating, diminishing the threat for additional heavy amounts and flash flooding across most of the region over the next couple of hours. Elsewhere, trimmed back the southwestern extent of the outlook areas that extended back into eastern Texas. However, maintained a broad Slight Risk area covering much of the Mid Mississippi Valley and Ozark Region, where models are maintaining a notable signal for heavy rain and potential flash flood development overnight. Storms currently over Missouri are expected to continue to train to the north over the next few hours, before storms begin to develop back to the southeast across portions of eastern Oklahoma, northwestern Arkansas, southeastern Kansas, and southwestern Missouri. While continuing to differ on the details, hi-res guidance including recent runs of the HRRR, show the potential for locally heavy amounts of 3 inches or more across this region overnight. Pereira Day 2 Valid 12Z Mon Jun 08 2026 - 12Z Tue Jun 09 2026 ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE MID-MISSISSIPPI, LOWER OHIO, AND TENNESSEE VALLEYS... On Monday, the northern stream cyclone will move north into Canada, while the leading shortwave trough and embedded MCV activity pushes east across the Midwest and Tennessee Valley. At the same time, a cold front sinking southward along the Carolinas will drape as a stationary front into the Ohio Valley and Midwest. Heavy rainfall potential will be focused in the warm sector of the system over the Mid- Mississippi, lower Ohio, and Tennessee Valleys where a very moist and unstable air mass will still be in place. The splitting upper level shortwave will push some energy across these regions, which will support a broad area of widespread/numerous thunderstorms. With weakening steering flow and remnant MCVs from earlier convection, storm motions are expected to become very slow, which will heighten the threat of flash flooding. One of these MCVs may be producing ongoing heavy rainfall across the Ozarks and into northeast OK and southeast KS at the start of the Day 2 forecast period Monday morning, which prompted the upgrade to a Slight Risk here. By midday Monday and into the evening hours, the flash flooding risk is expected to span from WI/IL south- southeast to the southern Appalachians and Tennessee Valley. These numerous slow-moving thunderstorms are forecast to contain at least 2"/hr rates at times and create scattered instances of flash flooding. Then, a final round of efficient rain- producing thunderstorms may occur across the lower Ohio and Tennessee valleys near the southwest inflow sector of a potent MCV overnight Monday. Currently, there remains high uncertainty with the exact location of this feature, but CAMs depict the potential for 5-7" rainfall totals near western KY and western/middle TN. The HREF shows impressive neighborhood probabilities (40-60%) of 24-hr rainfall totals exceeding 5 inches in this region. Some of these areas within the Slight Risk will also receive heavy rainfall during the day 1 period, which may increase the risk of flash flooding if areas are impacted by additional storms with heavy rainfall on Monday. Isolated pockets of significant impacts are possible and these areas will be monitored for future upgrades should confidence in locations of extreme rainfall increase. Outside of the Slight Risk area, a broad Marginal Risk area extends into the Upper Midwest and central Plains. Anomalous moisture will surge north behind the lifting warm front, which will support locally heavy rainfall that may lead to isolated instances of flash flooding for the western Great Lakes states. Models have also started consistently showing a potential MCS forming underneath a potent upper level shortwave moving quickly east across the central Plains on Monday evening. Though this feature would likely be progressive, it could have the potential to produce heavy rainfall and isolated flash flooding. There is still some uncertainty regarding the location of this feature, resulting in a broad Marginal Risk area that will likely be narrowed down over the next few forecast cycles. Dolan/Snell Day 3 Valid 12Z Tue Jun 09 2026 - 12Z Wed Jun 10 2026 ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE UPPER MIDWEST AND OHIO AND TENNESSEE VALLEYS... On Tuesday, an upper level trough will move across the northwestern U.S. and support cyclogenesis over the northern Plains. A wave of convection is expected to form ahead of the developing cyclone, bringing thunderstorms to much of the Upper Midwest. A moist and unstable air mass will be in place across the Upper Midwest after a warm front lifts north on Monday, which will support heavy rainfall in thunderstorms. Flash flood potential should be limited by the progressive nature of this system, but locally heavy rainfall could still lead to isolated instances of flash flooding, especially where soils will be moistened from rainfall expected on Sunday and Monday. A Marginal Risk area seems sufficient to cover the flash flood threat at this time. Another Marginal Risk area is in place for much of the Ohio and Tennessee Valleys and portions of Michigan where a slow moving frontal boundary will linger through Tuesday. This frontal boundary will provide modest lift/support for scattered convection across these regions. An anomalously moist air mass will still be in place, which should be enough to support locally heavy rain in some stronger storms and may lead to isolated instances of flash flooding. The flash flood threat will be significantly lower for these regions than on Monday with much weaker synoptic support. Dolan/Snell Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt