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Mesoscale Discussion 1109
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   Mesoscale Discussion 1109
   NWS Storm Prediction Center Norman OK
   0230 PM CDT Wed Jun 21 2017

   Areas affected...Parts of south central Nebraska...western
   Kansas...southeastern Colorado..northeast New Mexico and adjacent
   portions of the high Plains

   Concerning...Severe potential...Watch possible 

   Valid 211930Z - 212130Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Increasing thunderstorm activity is expected to be
   accompanied by a risk for severe hail and winds late this afternoon
   and evening.  While the potential for the evolution of an
   appreciable organized convective system seems relatively low, it is
   possible the the severe weather threat could require a watch at some
   point late this afternoon.

   DISCUSSION...Scattered thunderstorms appear to be in the process of
   initiating across the central/southern high Plains region, from the
   eastern and southern slopes of the Sangre De Cristo Mountains/Palmer
   Divide vicinity northeastward into southwestern Nebraska.  This
   appears to be occurring within the lee surface trough, where modest
   boundary layer moisture lingers and is contributing sizable CAPE in
   the presence of strong surface heating (temps now in the mid/upper
   90s).  With further boundary layer heating/mixing, activity is
   expected to continue to gradually intensify and increase in
   coverage, perhaps aided by forcing associated with a weak upper
   impulse or two digging southeastward, and around the northeastern
   periphery of the southwestern subtropical high.

   With thermodynamic profiles becoming characterized by a hot and
   deeply mixed boundary layer, with steep mid-level lapse rates and
   CAPE on the order of 2000+ J/kg, the environment appears conducive
   to at least some risk for severe hail initially.  This should be
   followed by increasing potential for localized strong downbursts
   later this afternoon, as light westerly/northwesterly deep layer
   mean flow supports a southeastward propagation across the high
   Plains through early evening.

   ..Kerr/Weiss.. 06/21/2017

   ...Please see for graphic product...


   LAT...LON   37910427 38750290 39180184 39830124 40530043 40169818
               38299894 35250296 34940433 37910427 

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