ZCZC SPCSWOMCD ALL ACUS11 KWNS 181708 SPC MCD 181708 ILZ000-MOZ000-181915- Mesoscale Discussion 0481 NWS Storm Prediction Center Norman OK 1208 PM CDT Thu Apr 18 2024 Areas affected...parts of central and southern Missouri into western Illinois Concerning...Severe potential...Watch likely Valid 181708Z - 181915Z Probability of Watch Issuance...80 percent SUMMARY...A gradual increase in thunderstorms is forecast across the central Missouri vicinity this afternoon, spreading into western Illinois with time. WW issuance is likely to be required in the next 1 to 2 hours. DISCUSSION...Latest visible satellite imagery shows a cold front extending southwestward from a low southeast of Kansas City, across far southeastern Kansas, and a warm front extending eastward across central Missouri. The warm front continues to move slowly northward, at the northern edge of a moist (60s dewpoints) boundary layer. In the wake of a well-defined, southeastward-moving gravity wave, preceding the frontal zone by about 100 miles, clearing in the cloud cover will continue to allow diurnal heating of the moistening boundary layer. Resulting moderate destabilization through the afternoon will support gradual development of storms -- initially in proximity to both frontal zones. With time, CAMs suggest some warm-sector/pre-frontal storm development, with any such storm more likely to exhibit supercell structures, given a background kinematic environment supportive of updraft rotation. Along with locally damaging wind gusts and possibly a tornado or two, large hail near or in excess of golf-ball size would be possible. However, more widespread severe risk may preferentially evolve with upscale-growing convection near the low and trailing cold front. Eventually, a broken line of storms is anticipated, accompanied by potential for more widespread damaging winds, along with hail and perhaps a QLCS tornado or two as it moves eastward across eastern Missouri and eventually into Illinois. ..Goss/Mosier.. 04/18/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...PAH...ILX...LSX...SGF...EAX... LAT...LON 38309410 39019288 39389094 39858891 38388828 37518923 37379383 37839429 38309410 NNNN