Mesoscale Discussion 0755
   NWS Storm Prediction Center Norman OK
   0544 PM CDT Wed May 26 2021

   Areas affected...Parts of northeastern Colorado...southwestern
   Nebraska...northwestern and north central Kansas

   Concerning...Tornado Watch 209...210...

   Valid 262244Z - 270045Z

   The severe weather threat for Tornado Watch 209, 210 continues.

   SUMMARY...Increasing and intensifying thunderstorm development into
   the 7-9 PM CDT time frame.  This will probably continue to include a
   few supercells with increasing tornadic potential, along with
   potential for the evolution of organizing thunderstorm clusters. 
   Areas to the east of the Tornado Watches will continue to monitored
   for additional severe weather watches.

   DISCUSSION...Although isolated to widely scattered thunderstorms are
   now initiating along the dryline, a much more substantive increase
   in thunderstorms is underway along a corridor from the Russell, KS
   vicinity northwestward through the McCook and Scottsbluff areas of
   western Nebraska.  This appears focused within a broad zone of
   lower/mid tropospheric warm advection, northeast of somewhat warmer
   and more strongly capping elevated mixed-layer air (as inferred from
   700 mb thermal fields).

   Storms near Russell also appear focused near a zone of locally
   enhanced boundary-layer convergence, near the eastern periphery of a
   20-30 kt southerly 850 mb jet, which is forecast to strengthen to 40
   kt this evening.  While there may be a tendency for this convection
   to begin to advect eastward, in the presence of 20-30 kt
   west-southwesterly ambient deep-layer mean flow, until the low-level
   jet begins to veer later this evening, strong storm development
   probably will remain focused near/west-northwest of the Russell
   vicinity.

   Otherwise, a general increase and intensification of thunderstorm
   activity probably will continue across parts of the Nebraska
   Panhandle and southwestern into south central Nebraska through
   00-02Z, with a tendency for activity to advect east/northeast of the
   Tornado Watch area.  However, strongest storms, including discrete
   supercells and upscale growing clusters, probably will remain
   focused near the edge of the warmer/more strongly capping elevated
   mixed-layer air, where the more moist and strongly heated
   boundary-layer is characterized by large CAPE (up to 3000 J/kg).  

   As the southerly low-level jet begins to strengthen by early
   evening, the risk for tornadoes in discrete supercells will probably
   continue to increase, include potential for a couple of strong
   tornadoes.

   ..Kerr.. 05/26/2021

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

   ATTN...WFO...TOP...ICT...GID...LBF...DDC...GLD...BOU...CYS...

   LAT...LON   41500332 41890128 40199887 39159704 38459875 38990054
               40200205 40930315 41500332