SPC MD 1089

MD 1089 CONCERNING SEVERE POTENTIAL...TORNADO WATCH LIKELY 311... FOR NORTHEAST MISSOURI...SOUTHERN INTO EASTERN IOWA...FAR WESTERN ILLINOIS Mesoscale Discussion 1089 NWS Storm Prediction Center Norman OK 0108 PM CDT Thu Jun 11 2026 Areas affected...northeast Missouri...southern into eastern Iowa...far western Illinois Concerning...Severe potential...Tornado Watch likely 311... Valid 111808Z - 112045Z Probability of Watch Issuance...95 percent SUMMARY...The environment is becoming more favorable for severe storms with potential for tornadoes, and new/updated tornado watches are likely over parts of Iowa, Missouri, and Illinois. DISCUSSION...Recent satellite and surface observations indicate a modifying/retreating outflow boundary into south-central IA where winds are now out of the south and with low 70s F dewpoints. Meanwhile, the synoptic cold front continues to push rapidly east, along with the shortwave trough. This front is located from central IA into northwest MO as of 18Z with gusty southwest winds ahead of it. GPS PWAT is over 1.80" now into southern IA. Low-level shear is quite favorable for rotating storms near the retreating outflow, with 0-1 SRH over 200 m2/s2. Over the next few hours, storms are likely to develop near the cold front, and perhaps within the warm advection zone near the modifying outflow boundary. Supercells are expected initially with deep-layer shear near 55 kt and ample low-level SRH to support rightward cell propagation relative to the cold front orientation. A few strong tornadoes will be possible. Damaging winds also are likely as high-PWAT air mass supports ample downdraft material with any larger storm clusters or linear modes near the cold front. ..Jewell/Gleason.. 06/11/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ILX...LSX...DVN...DMX...EAX... LAT...LON 40359360 40869338 41379301 41469282 41699196 41769157 41699111 41429084 41019079 40589079 40169089 39919133 39899157 39739279 39759326 40119358 40359360 MOST PROBABLE PEAK TORNADO INTENSITY...140-170 MPH MOST PROBABLE PEAK WIND GUST...65-80 MPH MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN Read more