ZCZC SPCSWOMCD ALL ACUS11 KWNS 121515 SPC MCD 121515 KYZ000-INZ000-ILZ000-MOZ000-121715- Mesoscale Discussion 1128 NWS Storm Prediction Center Norman OK 1015 AM CDT Sun Jun 12 2022 Areas affected...Parts of east central Missouri and central/southern Illinois and Indiana Concerning...Severe potential...Watch unlikely Valid 121515Z - 121715Z Probability of Watch Issuance...20 percent SUMMARY...It currently appears most probable that ongoing strong thunderstorm development will tend to wane through midday. However, until it does, occasional severe hail and locally strong surface gusts will remain possible. DISCUSSION...Ongoing storms slowly approaching the Interstate 70 corridor might be aided by forcing associated with a subtle short wave impulse progressing around the northeastern of prominent mid-level ridging centered over the southern Great Plains. This is also near and east of the plume of much warmer and more strongly capping elevated mixed-layer air spreading east of the Great Plains. As the weak impulse progresses into the lower Ohio through this afternoon, and much more prominent upstream mid-level troughing progresses inland of the Pacific coast, models suggest that the warmer and more strongly capping elevated mixed-layer air will continue to spread east of the mid/lower Mississippi Valley vicinity. Based on forecast soundings, among other model output, it appears that this may occur faster than any eastward advection of the higher boundary-layer moisture content (supportive of the large CAPE), which may remain focused near/west of the Mississippi Valley, closer to deeper surface troughing across the Great Plains. Given expected trends for increasing mid-level inhibition and weakening supporting forcing for ascent, it remains unclear how much longer stronger thunderstorm development supportive of severe hail and strong surface gusts will be maintained. ..Kerr/Guyer.. 06/12/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILN...LMK...IND...PAH...LOT...ILX...LSX... LAT...LON 39538997 40098916 40758824 40198608 39708497 38958481 38328743 37938929 38209032 38759050 39538997 NNNN