ZCZC SPCSWOMCD ALL ACUS11 KWNS 111959 SPC MCD 111959 MOZ000-IAZ000-KSZ000-NEZ000-112130- Mesoscale Discussion 1118 NWS Storm Prediction Center Norman OK 0259 PM CDT Sat Jun 11 2022 Areas affected...portions of eastern Nebraska southwestern Iowa and far northern Kansas/Missouri. Concerning...Severe potential...Watch likely Valid 111959Z - 112130Z Probability of Watch Issuance...80 percent SUMMARY...Strong to severe storms including supercells appear increasingly likely late this afternoon into this evening along the Missouri River Valley and into southwestern IA. Large to very large hail, damaging wind gusts and a few tornadoes will be possible. A Tornado watch will likely be needed by 20-22z. DISCUSSION...As of 1950Z, regional visible imagery showed cumulus towers exhibiting initial glaciation/deepening ahead of a weak vortmax/surface low across eastern NE. Several prominent surface boundaries within proximity to the low were acting as a focus for low-level convergence ahead of a subtle 500 mb trough within northwesterly flow aloft. As ascent and strong afternoon heating continue, (surface temps in the upper 80s low 90s F) objective analysis suggests remaining inhibition will likely diminish to breakable levels in the next couple of hours. Surface dewpoints in the upper 60s to low 70s F along with steep mid-level lapse rates of 8 C/km are supporting 2500-3000 J/kg of MLCAPE across eastern NE, southwestern IA into portions of northern KS/MO. 50 to 60 kts of effective shear are evident in long hook shaped hodographs from area soundings/VAD VWPS. This wind profile will initially support supercells capable of large to very large hail (2+ in), and strong outflow winds. A few tornadoes also appear possible with the more discrete storms owing to backed surface flow and enlarged low-level hodographs along the surface boundaries. Current hi-res model and observational data suggest storm development is likely within the next couple of hours near peak heating. While some uncertainty exists on the western and eastern limits of the severe potential, the environment appears highly favorable for supercells across much of the Missouri valley Region. This suggests a weather watch is likely needed in the next couple of hours. ..Lyons/Bunting.. 06/11/2022 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DMX...EAX...OAX...TOP... LAT...LON 40089707 40639728 41339736 42019703 42179664 42209624 42199532 41999475 41839442 41609404 40579373 40079403 39659485 39539529 39509564 39509601 39539668 40089707 NNNN