ZCZC SPCSWOMCD ALL ACUS11 KWNS 170118 SPC MCD 170118 TNZ000-KYZ000-170215- Mesoscale Discussion 0830 NWS Storm Prediction Center Norman OK 0818 PM CDT Fri May 16 2025 Areas affected...Middle and Eastern Tennessee Concerning...Severe potential...Watch likely Valid 170118Z - 170215Z Probability of Watch Issuance...80 percent SUMMARY...A tornado watch will be need this evening for Middle and Eastern Tennessee, as a line of supercell thunderstorms has developed along a surface cold front and begun moving east-southeastward. Potentially strong tornadoes, damaging winds of 60-80 MPH, and large hail are all possible with severe storms this evening. DISCUSSION...Ongoing severe thunderstorms extending from southwestern Kentucky into northern Arkansas are expected to persist and move southeastward into Middle and Eastern Tennessee this evening. 00Z sounding data from OHX shows modest to strong low-level shear, with 0-1 km SRH of 220 m^2/s^2, little to no remaining capping, and a deep effective inflow layer -- all supportive of supercells capable of producing tornadoes. However, with shear vector components being largely boundary-parallel, and some recent trends in upscale growth evident on radar, a transition from isolated supercells to supercells embedded in a quasilinear convective system is anticipated. As this transition occurs, the threat will shift from tornadoes to a damaging wind threat, with wind gusts of 60-80 MPH possible with the strongest thunderstorm outflow. Any tornadoes that do develop have the potential to be strong, and tornado watch issuance will be needed soon. ..Halbert/Gleason.. 05/17/2025 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...MRX...JKL...OHX...HUN...MEG... LAT...LON 35858806 36388807 36608766 36598578 36608489 36558386 36538364 36498350 36408346 36338347 36158361 35668392 35368416 35128446 35128641 35148706 35168755 35388792 35858806 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 NNNN