SPC MD 803

MD 0803 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF MIDDLE/EASTERN TENNESSEE INTO SOUTHERN KENTUCKY Mesoscale Discussion 0803 NWS Storm Prediction Center Norman OK 1234 PM CDT Wed May 20 2026 Areas affected...portions of Middle/eastern Tennessee into southern Kentucky Concerning...Severe potential...Watch unlikely Valid 201734Z - 201930Z Probability of Watch Issuance...20 percent SUMMARY...Widely scattered thunderstorms may pose a risk for isolated damaging wind gusts and small to marginally severe hail through this evening. Watch issuance is unlikely at this time. DISCUSSION...Recent radar imagery depicts increasing thunderstorm coverage across portions of Middle/eastern Tennessee and southern Kentucky amid continued diurnal heating of a moist low-level air mass (dewpoints in the mid/upper 60s F). Latest objective analysis depicts only weak buoyancy across the region, with MLCAPE around 500 J/kg. Further destabilization is expected through peak heating this afternoon, a modified 12z BNA observed sounding suggesting that MLCAPE is likely approaching 1000 J/kg based on recent surface observations. While deep-layer flow remains weak across the region (less than 30 kts of flow sampled through the column by the latest OHX VWP), 20-25 kts of effective shear should be sufficient to support modest updraft organization into a multicellular storm mode. In conjunction with steepening low-level lapse rates, this may promote the potential for gusty to isolated damaging wind gusts (likely in the 40-50 mph range) with any stronger, more well-organized clusters. Isolated small to marginally severe hail may also accompany the most robust updrafts despite poor mid-level lapse rates (5.5-6.0 C/km per latest mesoanalysis). Given the expectation for severe coverage/magnitude to remain limited, watch issuance is unlikely at this time. ..Chalmers/Hart.. 05/20/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MRX...JKL...LMK...OHX...HUN... LAT...LON 35788453 35418508 35058572 35018638 35208688 35548695 35958683 36358658 37218594 37588530 37558493 37368442 37068389 36748381 36258391 35788453 MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN Read more