Mesoscale Discussion 0709
   NWS Storm Prediction Center Norman OK
   0544 PM CDT Mon May 20 2019

   Areas affected...Much of Oklahoma and portions of western north
   Texas

   Concerning...Tornado Watch 199...

   Valid 202244Z - 202345Z

   The severe weather threat for Tornado Watch 199 continues.

   SUMMARY...The severe threat continues across WW 199.  A volatile
   environment remains in place across the discussion area with all
   modes of severe (including significant tornadoes) remaining
   possible.

   DISCUSSION...In the short term, tornado potential appears to be
   maximized in a couple of areas - one over Greer County, OK (where
   recent radar trends indicate potential for significant tornadoes and
   very large hail) and near Noble/Payne Counties in OK where a
   forward-propagating linear segment may interact with an outflow/warm
   frontal boundary immediately downstream of that region. 
   Surface-based storms continue in a very volatile shear/instability
   combination, with all modes of severe remaining possible (including
   significant tornadoes).  Shear will only increase in response to
   significant strengthening of low-level flow through the evening.

   A convectively modified surface boundary continues to migrate slowly
   southward across west-central Oklahoma and resides along a line from
   near PNC to just south of CSM and westward to south of AMA.  Storms
   north of this boundary will be elevated, but capable of large hail. 
   If the current storm near Greer County, OK can continue on the warm
   side of the boundary, it will continue with a risk of occasional
   strong to violent tornadogenesis in addition to large hail and
   damaging wind gusts.

   ..Cook.. 05/20/2019

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

   ATTN...WFO...OUN...LUB...AMA...

   LAT...LON   34820037 35489911 36019800 35849744 34419956 34820037