Mesoscale Discussion 1628
   NWS Storm Prediction Center Norman OK
   1156 AM CDT Sat Aug 29 2020

   Areas affected...Southern Missouri and northern Arkansas

   Concerning...Severe potential...Watch possible 

   Valid 291656Z - 291830Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Increasing storm coverage and intensity is expected
   through the afternoon. A severe thunderstorm watch may eventually be
   needed.

   DISCUSSION...A morning MCS produced a swath of damage from southeast
   Kansas into southwest Missouri before weakening over the past 1 to 2
   hours. The airmass ahead of this airmass has warmed substantially
   with temperatures in the upper 80s and dewpoints in the mid to upper
   70s yielding MLCAPE of 2000 to 3000 J/kg in northern Arkansas. In
   addition, SPC mesoanalysis shows this warming boundary layer has
   sufficiently eroded MLCIN on the southern portion of the remnant
   MCS. As a result, robust, surface-based convection has begun with an
   expanding cumulus field evident on visible satellite ahead of this
   activity. Effective shear is not that strong (20-30 kts per SPC
   mesoanalysis), but a favorable thermodynamic environment
   characterized by strong instability and moderate mid-level lapse
   rates around 7-7.5 C/km per SPC mesoanalysis will support a threat
   for both large hail and damaging winds. The primary limiting factor
   will be the lack of stronger shear, especially as storms move south
   with the outflow boundary into an area with weaker mid-level flow.
   Therefore, storm mode is expected to be messy with outflow
   boundaries and occasional bowing segments. Despite the messy storm
   mode, the thermodynamic environment will likely be sufficient to
   support a severe weather threat worthy of a severe thunderstorm
   watch later this afternoon, but the exact timing remains uncertain.

   Farther north in southern Missouri, the morning MCS will continue
   eastward along the instability gradient. Cooler, more stable
   conditions in this region may limit the threat in the near term, but
   stronger mid-level shear and a well developed cold-pool should help
   the threat persist. Eventually these storms will move into a more
   unstable airmass in southeast Missouri. An increase in storm
   intensity/additional storm development may occur in this region
   later this afternoon as a result.

   ..Bentley/Grams.. 08/29/2020

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

   ATTN...WFO...PAH...MEG...LSX...LZK...SGF...TSA...

   LAT...LON   36339403 36949364 37489328 37679281 37959179 37788993
               37138930 35828974 35259022 34709136 34509328 34929418
               35489435 36339403