ZCZC SPCSWOMCD ALL ACUS11 KWNS 010055 SPC MCD 010055 IAZ000-ILZ000-MOZ000-010230- Mesoscale Discussion 0583 NWS Storm Prediction Center Norman OK 0755 PM CDT Tue Apr 30 2024 Areas affected...Southeast IA...Northwest IL Concerning...Tornado Watch 163... Valid 010055Z - 010230Z The severe weather threat for Tornado Watch 163 continues. SUMMARY...Convection should gradually weaken as it spreads toward the Mississippi River Valley. New watch is not anticipated downstream. DISCUSSION...A few supercells linger across southern IA, along the southern fringe of large-scale support, in association with ejecting short-wave trough. Most notable, longer-lived supercell is propagating east across Appanoose County is approaching an air mass that is increasingly hostile to surface-based updrafts. While low-level lapse rates were steep at 00z/DVN, MLCAPE was only 40 J/kg, and nocturnal cooling will limit further destabilization. While this lead storm may produce marginally severe hail, or perhaps a brief tornado over the next hour or so, current thinking is convection should gradually weaken as the evening progresses. ..Darrow.. 05/01/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DVN...DMX... LAT...LON 41489297 41519118 40519098 40659329 41489297 NNNN