Subj : MESO: Mesoscale Discussion 0910 To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Tue May 20 2025 22:13:38 ACUS11 KWNS 202213 SWOMCD SPC MCD 202213=20 VAZ000-KYZ000-TNZ000-NCZ000-GAZ000-202315- Mesoscale Discussion 0910 NWS Storm Prediction Center Norman OK 0513 PM CDT Tue May 20 2025 Areas affected...Southern Appalachians Concerning...Severe potential...Watch likely=20 Valid 202213Z - 202315Z Probability of Watch Issuance...80 percent SUMMARY...A severe threat is expected to develop across parts of the southern Appalachians over the next couple of hours. Tornadoes, wind damage and isolated large hail will be possible. Weather watch issuance will likely be needed. DISCUSSION...Latest mosaic radar imagery shows a relatively large cluster of severe storms over the Tennessee Valley. Ahead of the storms, a moderately unstable airmass is in place. Further east, into eastern Tennessee and eastern Kentucky, the airmass was negatively impacted by a line of thunderstorms earlier today. In the wake of these storms, airmass recovery is taking place, and surface temperatures have already increased into the mid to upper 70s along the I-75 corridor from near Lexington southward to Knoxville. As surface heating continues, moderate instability is expected to re-develop along much of this corridor. This will contribute to a severe threat this evening, as the storms over middle Tennessee and western Kentucky move eastward. Regional WSR-88D VWPs at Jackson, KY and Morristown, TN have 0-6 m shear in the 35 to 40 knot range. The Jackson VWP has 0-3 km storm-relative helicity near 400 m2/s2. As cell coverage starts to increase, this environment should support a tornado, wind-damage threat and isolated large hail threat. If a cell can remain discrete and become dominant, then a locally greater tornado threat would be possible. It also remains possible that storms will congeal into one or more short-line segments. If that were to occur, then the wind-damage threat would increase as the storms move into the area from the west. ...Broyles/Gleason.. 05/20/2025 ....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-CkAC-BDP4C-hGm77I_HvV1kbMxCiHLPROkjndzDCK5t3DiGWzxorb9d2M4HKZNPwQ6R69wHq= O5JfUbVPN5MQbVTC28$ for graphic product... ATTN...WFO...GSP...MRX...JKL...FFC...LMK...OHX... LAT...LON 35238489 34898465 34878416 35618325 36538293 37418291 37838311 38078355 38208432 38078466 37828490 37428492 36668485 35658489 35238489=20 MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.20-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .