Mesoscale Discussion 0625
   NWS Storm Prediction Center Norman OK
   0641 PM CDT Sun May 17 2020

   Areas affected...central Louisiana

   Concerning...Severe potential...Watch unlikely 

   Valid 172341Z - 180115Z

   Probability of Watch Issuance...20 percent

   SUMMARY...The potential for a brief, weak tornado will persist for
   the next 1-2 hours as storms move southward across central
   Louisiana. However, given the low probability for multiple
   tornadoes, a watch is not expected.

   DISCUSSION...Thunderstorms ongoing across central LA along and ahead
   of a surface trough have shown signs of low-level rotation over the
   past 30-60 minutes (per KLCH and KPOE) with one tornado already
   reported along the LA Gulf coast. This low-level rotation is likely
   being driven by effective SRH values between 100-200 m2/s2 sampled
   by regional radar VWPs, especially across central to southern LA
   where low level winds are more west to southwesterly - enhancing
   directional shear in the lowest 1-2 km. With sufficient (500-1000
   J/kg) MLCAPE and 30-35 knots of effective bulk wind shear, these
   storms should be maintained and will pose the potential for a brief,
   weak tornado or two before they move into the more stable, cold-pool
   air across southern LA. The tornado threat will be maximized by any
   storm that can remain relatively discrete, and given numerous storm
   interactions and destructive interference already ongoing, the
   probability for numerous tornadoes is low. Due to these
   considerations, a watch is not expected.

   ..Moore/Hart.. 05/17/2020

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

   ATTN...WFO...LCH...SHV...

   LAT...LON   31479342 31669281 31539231 31079198 30739198 30429239
               30319286 30259324 30389351 31029344 31479342