Subj : Flood Threat Ozarks/OhioV To : All From : Mike Powell Date : Fri Jun 26 2026 13:03:12 AWUS01 KWNH 261742 FFGMPD TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-OKZ000-KSZ000-262340- Mesoscale Precipitation Discussion 0531 NWS Weather Prediction Center College Park MD 140 PM EDT Fri Jun 26 2026 Areas affected...Portions of the Ozark Plateau into the Lower Ohio Valley Concerning...Heavy rainfall...Flash flooding likely Valid 261740Z - 262340Z SUMMARY...Heavy showers and thunderstorms will be gradually redeveloping and expanding in coverage this afternoon and into the evening hours. High rainfall rates locally exceeding 2 inches/hour are expected, and with generally wet antecedent conditions and high streamflows, there will likely be new areas of flash flooding. DISCUSSION...Visible satellite imagery along with surface observations show a broad area of low pressure over eastern KS which is advancing slowly off to the east toward areas of western MO. This is traversing a frontal zone draped generally west to east from the central Plains eastward into the OH Valley. Despite substantial morning cloud cover, the warm-sector airmass pooling along this front and ahead of the surface low has been gradually destabilizing with MLCAPE values of 500 to 1000 J/kg across central MO through southern IL. However, much stronger thermodynamics are noted over the Ozark Plateau where MLCAPE values have risen to 1500 to 2000 J/kg. The environment is very moist with PWs on the order of 1.5 to 2 standard deviations above normal with values of 1.8 to 2.2 inches. This very moist and increasingly unstable airmass will be in place as some modest, low-amplitude shortwave energy embedded within the mid-level westerly flow traverses the region going through the afternoon hours. The result will be the development and expansion of heavy showers and thunderstorms that will be capable of producing rainfall rates as high as 1.5 to 2.5 inches/hour. A combination of weak DPVA, low-level moisture convergence near and south of the front, and relatively divergent flow aloft will help facilitate the convective threat. Some modest shear also is noted which may favor some relatively organized multicell bands of heavier showers and thunderstorms that may support these higher rainfall rates. The latest HRRR guidance and the 12Z HREF/REFS solutions show increasing coverage of convection over the next several hours with some localized rainfall totals reaching 3 to 4+ inches by early this evening. Areas east of the Ozark Plateau including southeast MO (near Cape Girardeau), southern IL (near Carbondale), and southern IN (approaching Evansville) are generally favored to see the heaviest totals for this nowcast period. However, by early this evening, convection should develop and become increasingly more focused across the Ozark Plateau including southwest MO, northern AR and back into northeast OK. Most of the region is generally quite sensitive, with wet antecedent conditions. The additional rainfall potential over the next several hours, and especially by this evening, will strongly favor runoff concerns and a likelihood for more areas of flash flooding. Orrison ATTN...WFO...EAX...ICT...ILX...IND...LMK...LSX...LZK...MEG... OHX...PAH...SGF...TSA... ATTN...RFC...KRF...MSR...ORN...TIR...TUA...NWC... LAT...LON 39139036 39028778 38288575 37268568 36758674 36628738 36308870 35718997 35369071 34899205 34929399 35269514 35799599 36649623 37519554 38469398 38969224 $$ --- SBBSecho 3.28-Linux * Origin: Capitol City Online (618:250/10) .