SPC MD 993

MD 0993 CONCERNING SEVERE POTENTIAL...WATCH POSSIBLE FOR PORTIONS OF SOUTHERN IOWA INTO FAR NORTHERN MISSOURI Mesoscale Discussion 0993 NWS Storm Prediction Center Norman OK 0819 PM CDT Fri Jun 05 2026 Areas affected...portions of southern Iowa into far northern Missouri Concerning...Severe potential...Watch possible Valid 060119Z - 060245Z Probability of Watch Issuance...40 percent SUMMARY...Isolated severe storm development is possible over southern IA this evening. The environment is conditionally supportive of a damaging wind and hail risk. The need for a WW is unclear. DISCUSSION...Evening satellite imagery showed an expanding cumulus field along a diffuse Theta-E gradient across southern IA. Over the last hour, several cumulus towers have deepened near the boundary. Weak ascent from an upper trough visible on WV imagery is overspreading the area and could allow for isolated storm development/intensification this evening, but this remains highly uncertain. The air mass along and south of the boundary is very moist with surface dewpoints in the upper 60s to low 70s F. This is supporting large buoyancy and little inhibition from SPC mesoanalysis. 30-40 kt deep-layer flow is supportive of marginal supercells and organized clusters. Given the parameter space (3000 J/kg MLCAPE + 30-35 kts EWD) these storms would be conditionally capable of damaging winds and hail. The primary uncertainty remains the development and maintenance of stronger storms. While SPC mesoanalysis and the 00z OAX sounding show little inhibition, the 00z DVN sounding and the slow evolution of the cumulus hint that inhibition remains fairly stout farther east. Given this uncertainty, it is unclear how intense or widespread these storms could be. CAM guidance suggests more robust development may be delayed until the arrival of the clusters ongoing farther west and the onset of a 20-25 kt low-level jet later this evening. While confidence in the convective evolution is low, some severe risk may materialize. Conditions are being monitored for a small Severe Thunderstorm Watch. ..Lyons/Gleason.. 06/06/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DVN...DMX...EAX... LAT...LON 41669314 41739166 41539131 41149127 40659194 40519291 40539378 40559439 40719487 41269488 41669314 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more