Mesoscale Discussion 1487 NWS Storm Prediction Center Norman OK 0356 PM CDT Wed Aug 11 2021 Areas affected...Portions of eastern IA...far northeastern MO...and northwestern IL Concerning...Severe potential...Watch possible Valid 112056Z - 112330Z Probability of Watch Issuance...40 percent SUMMARY...If storms develop and can be sustained, then the threat for large hail and damaging winds would increase. Convective trends will be closely monitored, with watch issuance possible. DISCUSSION...Recent attempts at convective initiation have been noted across eastern IA along/east of a surface cold front. This region is on the southern extent of an upper trough over central Canada and the Upper Midwest, with minimal mid-level height falls noted. Still, latest mesoanalysis suggests that airmass just ahead of the front is extremely unstable and uncapped, with MLCAPE of 3500-4500 J/kg present. Latest VWP from KDVN shows winds veering with height through mid levels and strengthening to around 45-50 kt above 3 km. Related 35-40 kt of deep-layer shear would be supportive of supercells. The presence of steep mid-level lapse rates and a very favorable thermodynamic environment suggests a threat for large hail with any supercell that can form and be sustained. Damaging downdraft winds would also be a concern. The main question is whether any robust storms will be able to form given the weak large-scale ascent aloft. This region will be closely monitored for signs of increasing convective coverage/intensity, with watch issuance possible.