Subj : Flood Threat MS/OH Valley To : All From : Mike Powell Date : Sat Jun 27 2026 08:19:21 AWUS01 KWNH 271201 FFGMPD VAZ000-WVZ000-OHZ000-TNZ000-KYZ000-INZ000-ILZ000-MOZ000-ARZ000-271800- Mesoscale Precipitation Discussion 0539 NWS Weather Prediction Center College Park MD 800 AM EDT Sat Jun 27 2026 Areas affected...Portions of the Middle MS and OH Valley Concerning...Heavy rainfall...Flash flooding likely Valid 271200Z - 271800Z SUMMARY...Regional concerns for flash flooding will continue over the next several hours going into the early afternoon hours. Repeating rounds of heavy shower and thunderstorm activity will support new areas of flash flooding, and locally significant impacts will be possible. DISCUSSION...The morning GOES-E IR satellite imagery along with regional radar data shows an elongated axis of broken shower and thunderstorm activity impacting areas of southern IL, southern IN, and multiple areas of central KY. More recently some of this activity has been edging into western WV as well. All of this convection is associated with multiple MCVs that are embedded within the westerly mid-level flow pattern across the Middle MS and OH Valley region. Much of the region is very moist, with PWs of 1.8 to 2.2 inches, and generally on the order of 2 to 2.5 standard deviations above normal for late June. The early morning OSPO ALPW data shows substantial moisture in the mid and upper-levels of the vertical column and supportive of tall, skinny CAPE profiles. This is a rather classic warm rain setup which is likely to result in extremely efficient convection for high-end rainfall rate potential. Already the ejecting vort energy is fostering sufficient lift for broken clusters/bands of convection, but with nearly unidirectional flow through the column, and upwind propagation vectors very weak and nearly opposing the deeper layer mean flow, we are going to see an environment conducive for backbuilding and training convection. Already some hints of this are noted over areas of far southern IN down through central KY. The MUCAPE values are on the order of 1000 to 2000 J/kg for much of the region, except for far eastern KY and western WV where they are more in the 500 to 1000 J/kg range. This coupled with the level of deep moisture in place and high WCL depths will support rainfall rates easily into the 2 to 3 inch/hour range, with even some potential for rates higher than this. Given the repeating/training nature of the heavy rainfall threat, some additional totals through 18Z (1PM CDT) may reach 3 to 5 inches, and there are multiple hires model CAMs that support this, although there is disagreement on the placement. Radar and satellite trends would favor areas of central KY probably seeing the best potential for this. But areas farther west across southeast MO into southern IL and southern IN will also see separate bands of convection with very heavy rainfall potential. The threat of flash flooding is increasing, and new areas of flash flooding are expected over the next several hours. This will include a threat for locally significant impacts going through early this afternoon. Orrison ATTN...WFO...ILN...ILX...IND...JKL...LMK...LSX...LZK...MEG... MRX...OHX...PAH...RLX...RNK...SGF... ATTN...RFC...KRF...MSR...ORN...TIR...NWC... LAT...LON 38998291 38658107 37608094 36748349 36528527 36338756 36249047 36519181 36969233 37569202 38049091 38378935 38548801 38768543 $$ --- SBBSecho 3.28-Linux * Origin: Capitol City Online (618:250/10) .