Storm Prediction Center Mesoscale Discussion 856

   Mesoscale Discussion 0856
   NWS Storm Prediction Center Norman OK
   0606 PM CDT Mon May 20 2024

   Areas affected...parts of south central and southeastern Nebraska

   Concerning...Severe potential...Watch possible 

   Valid 202306Z - 210100Z

   Probability of Watch Issuance...60 percent

   SUMMARY...Scattered strong thunderstorm development is initiating
   across the region and probably will persist into mid/late evening. 
   A few supercells are possible, primarily posing a risk for large
   hail.

   DISCUSSION...Deepening convective development is underway where
   boundary-layer destabilization has become maximized in a corridor
   from near the Hastings/Kearney vicinity into the Greater Omaha area.
   This is in advance of a slowly southeastward advancing cold front,
   where lower/mid-tropospheric warming across much of the central
   Great Plains may be offsetting weakening of inhibition associated
   with insolation.  Still, roughly to the north of the Kansas/Nebraska
   border, temperatures in the 700-500 mb layer remain cooler relative
   to areas to south, and it appears inhibition is weak enough to allow
   for intensifying thunderstorm development during the next few hours.

   Mid/upper support for upward vertical motion remains uncertain, but
   strong southwesterly flow in mid/upper levels is contributing to
   sufficient deep-layer shear for supercell development.  With
   mixed-layer CAPE in excess of 2000 J/kg beneath steep mid-level
   lapse rates, stronger storms may pose an initial risk for severe
   hail.  

   Although boundary-layer cooling will contribute to increasing
   inhibition into and after sunset, modest strengthening of southerly 
   850 mb flow and associated warm advection may maintain stronger
   cells into mid/late evening.

   ..Kerr.. 05/20/2024

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

   ATTN...WFO...OAX...GID...

   LAT...LON   40829950 41519778 41609607 40759563 40129661 39959878
               40219958 40829950