Storm Prediction Center Mesoscale Discussion 1172

   Mesoscale Discussion 1172
   NWS Storm Prediction Center Norman OK
   0743 PM CDT Wed Jun 17 2026

   Areas affected...Parts of southern LA/MS

   Concerning...Severe potential...Watch possible 

   Valid 180043Z - 180315Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A gradual increase in the tornado threat is expected into
   late evening. Watch issuance is possible.

   DISCUSSION...To the east of strongly sheared Tropical Storm Arthur,
   low-level flow is gradually increasing across parts of southeast LA
   and southern MS (as depicted in regional VWPs), and will continue to
   increase into late evening. Some backing of low-level flow is also
   expected as Arthur approaches the region, resulting in some
   enlargement of low-level hodographs. Given the presence of rich
   tropical moisture (with mid/upper 70s F dewpoints), this increase in
   low-level shear/SRH could aid in the development of transient, small
   supercells later this evening into the overnight, resulting in a
   threat for brief tornadoes. Tornado Watch issuance is increasingly
   possible later this evening in order to address this threat.

   ..Dean/Smith.. 06/18/2026

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

   ATTN...WFO...MOB...JAN...LIX...LCH...

   LAT...LON   29779315 31209181 31338996 31238912 31008865 30658870
               29558936 29079021 29039071 29069137 29219202 29779315 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
   MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH