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Mesoscale Discussion 712
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   Mesoscale Discussion 0712
   NWS Storm Prediction Center Norman OK
   0822 PM CDT Mon May 20 2019

   Areas affected...much of Oklahoma and western north Texas

   Concerning...Tornado Watch 199...

   Valid 210122Z - 210215Z

   The severe weather threat for Tornado Watch 199 continues.

   SUMMARY...The severe threat continues in portions of central and
   southern Oklahoma and western north Texas.

   DISCUSSION...Most of the storms in central Oklahoma have been
   undercut by an extensive outflow boundary located from northwest of
   TUL through OKC and LTS, with the most substantial surface-based
   activity now entering portions of Foard and Knox counties in Texas. 
   The undercutting nature of the outflow has tempered the tornado
   threat across much of central Oklahoma in the near-term, though hail
   and damaging wind gusts continue along and north of the outflow with
   training convection moving east-northeast.  In northeastern
   Oklahoma, however, surface-based parcels are still being ingested
   within a broken line of storms in that area, and strong
   shear/instability continues to support more of a threat for
   tornadoes and damaging wind gusts.

   More isolated convection south of the boundary continues to struggle
   against weak mid-level inhibition located at around 700 hPa on the
   00Z OUN RAOB.  The trend with this convection has been upward,
   however, with mesocyclones noted in relatively shallow convection
   just south of the Tulsa area.  If storms can continue to deepen
   within the pre-convective environment, the parameter space remains
   favorable for all modes of severe, including significant tornadoes. 
   Western north Texas convection will also have an increased threat
   for severe as it progresses eastward into an even more strongly
   sheared and unstable environment to its east.  

   Over time, increased forcing for ascent associated with the longwave
   trough now traversing New Mexico will foster upscale growth of
   storms into one or two linear complexes.  Damaging wind gusts and
   hail would be the most favored severe mode with this activity,
   though isolated tornadoes cannot be ruled out.  It is uncertain
   whether upscale growth in southern portions of the WW area will
   occur with ongoing activity in western north Texas or wait for
   stronger forcing aloft and redevelopment southwest of WW 199.

   ..Cook.. 05/21/2019

   ...Please see for graphic product...


   LAT...LON   35379984 35659902 36229794 36789672 36879615 36799566
               36039565 35089568 34359575 33839604 33809719 33629796
               33409864 33459954 33590002 34570014 35040004 35379984 

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