Mesoscale Discussion 0718
   NWS Storm Prediction Center Norman OK
   1255 AM CDT Tue May 21 2019

   Areas affected...southeast MO and adjacent southwest IL

   Concerning...Severe potential...Watch possible 

   Valid 210555Z - 210730Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Convection moving into parts of east-central MO toward the
   greater St. Louis metro area is expected to remain sub-severe,
   through some gusty winds are possible. Further south, a watch may
   become necessary across southeast MO and vicinity, but this remains
   uncertain at this time and trends will continue to be monitored.

   DISCUSSION...A bowing segment across south-central MO will continue
   to track east/northeast across southeast MO and southwest IL, on the
   cool side of a warm front draped southeastward from near Texas
   County MO toward the MO Bootheel/northeast AR and western TN.
   Regional surface observations from KVIH and others indicate wind
   gusts in the 30-40 kt range in the cooler air north of the boundary.
   While the warm front continues to slowly lift northward, expect that
   the current line exiting WW 201 into southern portions of WFO LSX
   should remain sub-severe as it outpaces weak instability and
   encounters poorer boundary-layer moisture.

   A little more uncertain is the southeast MO/northeast AR border
   vicinity where a better quality boundary layer exists along and just
   south of the warm front. Convection to the west of this area has
   generally shown a weakening trend late this evening in the absence
   of strong forcing for ascent. However, regional VWP from LZK and PAH
   88-D continue to indicate strong effective shear and large, curved
   hodographs that would tend to support organized structures.
   Additionally, convective mode has been messy this evening and storms
   have tended to be more outflow dominant in the deep, moisture-rich
   warm sector. Nevertheless, environmental parameter space is such
   that this area bears watching and a new watch may be needed across
   portions of southeast MO and perhaps adjacent southwest IL.

   ..Leitman/Edwards.. 05/21/2019

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

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

   LAT...LON   38319194 38559160 38739123 38789074 38769020 38628995
               37818927 36958913 36608923 36288948 36108997 36149052
               36239133 36409212 37129226 37449207 37779196 38319194