Mesoscale Discussion 1152
   NWS Storm Prediction Center Norman OK
   0711 PM CDT Sun Jul 04 2021

   Areas affected...Southeast Montana...far Northeast Wyoming...and far
   Northwest South Dakota

   Concerning...Severe potential...Watch unlikely 

   Valid 050011Z - 050215Z

   Probability of Watch Issuance...5 percent

   SUMMARY...Storms may become more organized this evening, posing an
   isolated wind/hail threat. Watch issuance unlikely.

   DISCUSSION...Regional radar shows a cluster of somewhat disorganized
   but marginally intense storms over southeast portions of Montana.
   Strong diabatic heating has resulting in hot surface temperatures
   into the mid 90s F, yielding strong low-level lapse rates. Weak
   easterly/upslope flow has allowed surface dew point temperatures to
   rise to near 50 F in proximity to the ongoing convection. The large
   temperature/dew point spread is resulting in inverted-v soundings,
   with weak instability (MLCAPE approaching 500 J/kg).

   Despite the weak low-level easterly flow, amid marginal westerly
   flow aloft, deep-layer shear remains rather weak (effective shear
   perhaps near 20 kt). However, forecast soundings indicate some
   potential for an increase in effective shear throughout the evening,
   perhaps approaching 30-35 kt by 03z, as low-level southeasterly flow
   increases. Thus, the ongoing convection may become a bit more
   organized if it can persist for a few more hours. Should this occur,
   storms will pose a threat for strong outflow wind gusts and severe
   hail. At this time, the threat is expected to remain fairly
   isolated/brief, and thus, watch issuance is not expected.

   ..Karstens/Hart.. 07/05/2021

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

   ATTN...WFO...BIS...UNR...BYZ...RIW...

   LAT...LON   44020469 44340601 44720729 45620728 46140637 46210441
               45760324 44670362 44020469