Mesoscale Discussion 0461
   NWS Storm Prediction Center Norman OK
   1239 PM CDT Sat May 19 2018

   Areas affected...Northern Oklahoma into southern Kansas

   Concerning...Severe potential...Watch likely 

   Valid 191739Z - 192015Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Storms are expected to form across northern Oklahoma into
   southern Kansas, with very large hail and a tornado or two possible.
   A watch will likely be needed by 20-21Z.

   DISCUSSION...Surface analysis shows a quasi-stationary boundary from
   northwest OK into southern MO, with a cold front just northwest from
   the TX Panhandle into east-central KS. Meanwhile, earlier storms
   have left behind an outflow boundary, close to the synoptic front
   along the KS/OK border.

   Visible satellite imagery shows heating is occurring in the
   post-outflow air mass, along with strong warming south of the main
   front where temperatures are rising into the mid 80s F. Although
   morning soundings showed a rather shallow moist layer from TX into
   OK, some deepening of the moist boundary layer is expected near the
   fronts, also aided by evapotranspiration. The presence of cold
   temperatures aloft combined with this warming air mass is resulting
   in strong instability with 700-500 mb lapse rates around 8.5 C/km.
   This suggests vigorous updrafts which will support very large hail.
   In addition, a tornado or two is possible in this region due to the
   locally backed surface winds near the modifying outflow, and aided
   by slight warm advection/lift atop this boundary.

   ..Jewell/Weiss.. 05/19/2018

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

   ATTN...WFO...TSA...ICT...OUN...DDC...

   LAT...LON   37279811 37719681 37789582 37619547 37169529 36709560
               36439690 36289810 36259846 36449870 36699879 36989860
               37279811