ZCZC SPCSWOMCD ALL ACUS11 KWNS 281456 SPC MCD 281456 NCZ000-GAZ000-TNZ000-ALZ000-MSZ000-281700- Mesoscale Discussion 0176 NWS Storm Prediction Center Norman OK 0856 AM CST Wed Feb 28 2024 Areas affected...TN Valley to southern Appalachians Concerning...Severe potential...Watch unlikely Valid 281456Z - 281700Z Probability of Watch Issuance...20 percent SUMMARY...Southern portion of a low-topped squall line should continue eastward across parts of the Tennessee Valley through at least midday. Strong to localized severe wind gusts capable of sporadic damage should be the primary threat. DISCUSSION...The southern portion of a long, but thin, low-topped (echo tops to around 30k ft) squall line extends as far south as northeast MS. Large-scale ascent, outside of low-level convergence attendant to the southeast-moving cold front, will be gradually weakening across the region into the afternoon. However, a few cloud breaks noted ahead of the line should yield modest boundary-layer destabilization. In conjunction with the northeast extent of low 60s surface dew points, the relatively more favorable thermodynamic environment should compensate for the diminishing ascent and will probably sustain the low-topped convective line eastward through at least midday. This scenario is generally supported by 12Z CAM guidance. With veered surface and low-level flow, increasing to 40-45 kts at 1 km AGL, the primary threat should be strong to locally severe surface gusts, peaking in the 50-65 mph range. A 53-kt gust was measured at KMSL at 1437Z. ..Grams/Guyer.. 02/28/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...GSP...MRX...FFC...OHX...BMX...HUN...MEG...JAN... LAT...LON 35578600 35818470 35458401 35098380 34608371 34258386 33948462 33558572 33448683 33518828 33618872 34638751 35578600 NNNN