ZCZC SPCSWOMCD ALL ACUS11 KWNS 010844 SPC MCD 010844 INZ000-ILZ000-IAZ000-011115- Mesoscale Discussion 1623 NWS Storm Prediction Center Norman OK 0344 AM CDT Mon Aug 01 2022 Areas affected...a small portion of southeastern Iowa...central Illinois and west central Indiana Concerning...Severe potential...Watch unlikely Valid 010844Z - 011115Z Probability of Watch Issuance...20 percent SUMMARY...One or two clusters of strong thunderstorms may be maintained southeastward across the region through daybreak, perhaps accompanied by occasional surface gusts approaching severe limits. DISCUSSION...Large-scale forcing for ascent associated with a notable short wave trough digging through the Upper Midwest has contributed to a southeastward propagating area of sustained vigorous thunderstorm development the past several hours. The primary cluster has been focused and rooted within an area of enhanced low-level warm advection now spreading southeast of the Mississippi River into north central Illinois. More recently, thunderstorms are initiating near the intersection of trailing associated outflow, and the leading edge of low-level cooling/drying associated with the upper impulse. This is also generally near the exit region of a digging 30-50 kt northwesterly jet streak (within the 850-500 mb layer). Various model output, including the latest High Resolution Rapid Refresh, suggests that this forcing may maintain activity east-southeastward across at least much of north central Illinois and west central Indiana by 12-13Z. Storms appear largely rooted above at least a couple thousand feet deep surface-based stable layer, with moist elevated inflow characterized by moderately large CAPE, though cloud-bearing layer shear may only be marginally sufficient for organized convection. Despite the strong rear inflow evident in radar data, the weakly unstable to stable low-level lapse rates may be inhibiting downward momentum transport to some degree, and there has been little evidence of strong gusts in surface observations as activity tracks southeastward around 35 kt. However, it is possible that heavy precipitation loading could support occasional, localized strong surface gusts approaching severe limits as long as convection maintains current strength. ..Kerr/Thompson.. 08/01/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...IND...LOT...ILX...DVN... LAT...LON 40868943 41108877 39948681 38868717 39818989 41279153 40868943 NNNN