Mesoscale Discussion 0250
   NWS Storm Prediction Center Norman OK
   0117 PM CDT Sat Mar 28 2020

   Areas affected...Southern Illinois...Southeast Missouri...and
   northeast Arkansas

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

   Valid 281817Z - 281945Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A gradual increase in severe storm potential is expected
   through mid-afternoon. A tornado watch will likely be needed by 19Z.

   DISCUSSION...Thick cloud cover has limited surface heating across
   most of southeast Missouri and northeast Arkansas today with more
   breaks in the clouds and warmer temperatures seen across southern
   Illinois. Upstream convective activity will continue to keep a cloud
   shield across most of this region. The only exception will be
   central Missouri where upper-clouds have started to dissipate and
   surface heating is increasing.

   Areas beneath the cloud shield are slowly destabilizing due to
   gradual warming temperatures, northward moisture advection, and
   cooling temperatures aloft. This will continue for the next few
   hours and eventually erode inhibition enough for surface based
   storms to develop along and ahead of the surface front this
   afternoon and into the evening. MLCAPE is expected to peak between
   1500 and 2000 J/kg across this region with effective shear around 60
   to 70 knots. This will support supercellular structures. 

   Considerable storm coverage across southeast Missouri and southern
   Illinois will likely lead to a messy storm mode and thus limit the
   overall intensity of the storms. Nonetheless, stronger updrafts will
   likely be present with a threat for all hazards including a couple
   of tornadoes. A few discrete storms are also possible ahead of the
   front which would pose a greater hail/tornado threat. Overall, any
   tornadoes in this region will likely remain relatively short-lived
   given the mostly long-straight hodographs and relatively veered
   surface flow. 

   Farther north, along and north of I-44 in Missouri, surface flow is
   strongly backed and temperatures/dewpoints are increasing. This
   region, in closer proximity to the surface low, will have a greater
   threat for longer-track tornadoes given the backed surface flow, and
   more discrete storm mode.

   ..Bentley/Goss.. 03/28/2020

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

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

   LAT...LON   37228828 36608895 36159018 36159135 36669218 37249249
               37919296 38519265 38959154 39348993 39468885 39508784
               39438752 38368777 38248781 37228828