Mesoscale Discussion 0258
   NWS Storm Prediction Center Norman OK
   0233 PM CDT Thu Mar 25 2021

   Areas affected...The mid-Mississippi River Valley and lower Ohio
   River Valley Region

   Concerning...Severe potential...Tornado Watch likely 

   Valid 251933Z - 252130Z

   Probability of Watch Issuance...80 percent

   SUMMARY...A tornado watch is likely in the coming hours as a surface
   low and associated warm front continue to lift northward through the
   late afternoon.

   DISCUSSION...Surface observations over the past couple of hours have
   shown 2-3 mb surface pressure falls over northeast AR into the lower
   OH River Valley region. The surface low located over northeast AR
   continues to consolidate and is expected to deepen further as it
   lifts to the north/northeast. As this occurs, an associated surface
   warm front will lift to the north and allow a higher theta-e air
   mass (noted by temperatures and dewpoints in the 60s) to overspread
   the mid-MS River Valley and lower OH River Valley regions and allow
   MLCAPE to increase into the 500-1000 J/kg range. Storms are forecast
   to develop along the surface warm front and surface trough in the
   vicinity of the low, and southwesterly 60-70 knots of effective bulk
   shear will help support discrete to semi-discrete storm modes. Along
   with a hail/wind threat, backed low-level winds within the open warm
   sector will support ESRH values on the order of 300 m2/s2 and a
   tornado threat with any discrete convection that can develop. Recent
   guidance suggests storm initiation within this region may occur
   within the 22-00 UTC time frame. A tornado watch will likely be
   needed in the coming hours to address this concern.

   ..Moore/Hart.. 03/25/2021

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

   ATTN...WFO...LMK...OHX...IND...PAH...ILX...MEG...LSX...

   LAT...LON   36498774 36148863 35988936 36238974 36718989 37438983
               38008958 38438912 38778824 38788726 38348672 37528679
               37008706 36498774