ZCZC SPCSWOMCD ALL ACUS11 KWNS 061808 SPC MCD 061808 INZ000-KYZ000-ILZ000-MOZ000-062015- Mesoscale Discussion 1650 NWS Storm Prediction Center Norman OK 0108 PM CDT Tue Aug 06 2019 Areas affected...eastern Missouri and into southern Illinois...southwestern Indiana...and western Kentucky Concerning...Severe potential...Watch likely Valid 061808Z - 062015Z Probability of Watch Issuance...80 percent SUMMARY...Thunderstorms are forecast to increase in coverage over the next 1-2 hours over the mid Mississippi and lower Ohio Valley area, along with an associated increase in severe potential. A watch will likely be required. DISCUSSION...Latest visible satellite imagery shows an increase in cu/cb across parts of eastern Missouri, northwest of the St. Louis area. The increase is occurring near a very weak/subtle frontal wave, associated with a mid-level disturbance moving southeastward across northwestern Missouri. With a very moist airmass undergoing continued heating/ destabilization (mixed-layer CAPE now exceeding 2500 to 3000 J/kg across much of the discussion area), an increase in convective development is expected to continue -- resulting in eventual strong/locally severe storm development. The latest LSX (St. Louis) WSR-88D VWP shows low-level flow veering to northwesterly in the lowest 1km, and then a roughly unidirectional northwesterly profile that increases in speed with height. This kinematic environment supports organized, southeastward-moving storms, with upscale growth into sustained storm clusters expected. Locally damaging wind gusts will likely be the primary risk, though hail is also possible. Given the expected/gradual increase in severe potential, a WW will likely be required in the next hour or so. ..Goss/Dial.. 08/06/2019 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IND...PAH...ILX...LSX... LAT...LON 39169132 39279082 39048936 38958805 38178753 37158773 36678865 36718970 37989101 39169132 NNNN