Storm Prediction Center Mesoscale Discussion 740

   Mesoscale Discussion 0740
   NWS Storm Prediction Center Norman OK
   1110 AM CDT Thu May 08 2025

   Areas affected...the Mid Mississippi Valley to the Southern
   Appalachians

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 081610Z - 081745Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Widespread thunderstorm development is expected this
   afternoon with a threat for large hail and damaging wind gusts.

   DISCUSSION...Cold temperatures aloft, associated with an eastward
   meandering upper low, will provide a focus for widespread
   thunderstorm development this afternoon from the Mid Mississippi
   Valley to the southern Appalachians. Beneath this cold air aloft,
   surface dewpoints are mostly in the mid 60s. This moisture will be
   sufficient for moderate instability this afternoon (~1500 J/kg
   MLCAPE) as temperatures warm into the mid 70s. A belt of moderate
   (40 to 45 knots) of mid-level flow exists south of this upper low
   and was apparent on the 12Z RAOB from KBNA and KLZK. This will
   provide a sufficiently sheared environment for organized storms
   including the potential for some rotating updrafts. This cold air
   aloft, yielding moderately steep mid-level lapse rates, and
   potential for some supercells will support a threat for large hail,
   some of which could be 2+ inches. A remnant EML and dry air aloft,
   combined with steep low-level lapse rates will also support a
   damaging wind threat. In addition, the expectation for many storms
   within the already uncapped airmass should promote storm clustering
   which will also increase the damaging wind threat within those
   corridors which clustering/bowing segments occur.

   The 12Z BNA RAOB showed a convective temperature of 73F which has
   nearly been reached as of 16Z. As such, a few storms have already
   developed over southeast Missouri and northwest Tennessee where
   cooler temperatures aloft are likely supporting a lower convective
   temperature. As the boundary layer warms and mid-level temperatures
   continue to cool, expect additional strong storm development within
   the next 1 to 2 hours. Multiple severe thunderstorm watches will be
   needed to address the threat from this development.

   ..Bentley/Gleason.. 05/08/2025

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...MRX...JKL...LMK...OHX...HUN...PAH...MEG...

   LAT...LON   35029014 36878979 37328902 37338742 37418598 37158449
               37028343 36648324 36288332 35098447 35028552 34548760
               34068914 34118994 35029014 

   MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN