Storm Prediction Center Mesoscale Discussion 249

   Mesoscale Discussion 0249
   NWS Storm Prediction Center Norman OK
   0634 PM CDT Wed Mar 19 2025

   Areas affected...Western and middle Tennessee into northern
   Mississippi and northwest Alabama

   Concerning...Severe potential...Watch unlikely 

   Valid 192334Z - 200130Z

   Probability of Watch Issuance...20 percent

   SUMMARY...Thunderstorm development is expected between 7-9 PM CDT
   across western Tennessee and northern to central Mississippi with a
   downstream risk for severe hail and damaging winds. The risk is
   expected to remain sufficiently isolated to preclude watch issuance.

   DISCUSSION...GOES visible imagery shows gradually deepening cumulus
   along and just ahead of a diffuse dryline/Pacific front from western
   TN southward into MS. This trend is expected to continue as
   mid-level temperatures continue to cool with the eastward
   progression of the primary trough axis, resulting in improving
   700-500 mb lapse rates that will be more favorable for sustained
   convection. This trend is already being observed further north
   across the lower OH River Valley, suggesting that thunderstorm
   development is becoming more likely for areas further south. Modest
   surface moisture (mid 50s dewpoints) will continue to limit overall
   buoyancy values (MLCAPE should be maximized around 500-750 J/kg),
   but wind fields over the region are supporting elongated hodographs
   that will promote organization of the more intense updrafts. Weak
   off-boundary storm motions/deep-layer shear vectors suggest that a
   combination of semi-discrete cells and clusters is likely later this
   evening as storms move into middle TN and northwest AL. Given the
   convective environment and trends in latest CAM guidance, a few of
   the more intense cells/clusters may pose a severe hail/wind threat
   through the late evening.

   ..Moore/Hart.. 03/19/2025

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

   ATTN...WFO...OHX...BMX...HUN...PAH...MEG...JAN...

   LAT...LON   32909031 35998919 36458887 36538846 36628750 36588700
               36448652 36178623 35758610 35048619 34208674 33358759
               32638848 32468899 32458937 32478982 32549002 32679022
               32909031