Mesoscale Discussion 1247
   NWS Storm Prediction Center Norman OK
   0903 PM CDT Tue Jun 10 2025

   Areas affected...parts of the south central Texas Rio Grande Valley

   Concerning...Severe Thunderstorm Watch 407...

   Valid 110203Z - 110400Z

   The severe weather threat for Severe Thunderstorm Watch 407
   continues.

   SUMMARY...Thunderstorm development may continue to intensify and
   gradually become better organized, accompanied by increasing
   potential for strong to severe surface gust as it approaches the
   I-35 corridor of Deep South Texas, including the Greater San Antonio
   area through 10 PM-Midnight CDT.

   DISCUSSION...Thunderstorms continue to develop along the leading
   edge of consolidating and strengthening convective outflow now east
   through south of Ozuna and Del Rio TX, and southwestward into the
   higher terrain to the west of the Rio Grande River.  2-hourly
   surface pressure rises in excess of 2 mb were evident in 01Z
   observations at these sites, with a 3-second peak gust to 57 kt
   recently measured at Del Rio.  

   It remains unclear if this outflow will be reinforced/overtaken by
   the remnants of outflow emanating from a decaying upstream cluster
   across the Pecos Valley, which generated a strong surface pressure
   perturbation including 2-hourly pressure falls and rises on the
   order of 4-5 mb across the Fort Stockton vicinity.  However, a very
   warm and well-mixed boundary layer near and west of the Rio Grande
   River, in advance of the intensifying convection remains
   characterized by temperature/dew points spreads on the order of 30
   F, with sufficient moisture in the presence of steep mid-level lapse
   rates to support CAPE up to around 3000 J/kg.  This remains
   conducive to strong downsbursts, and further cold pool strengthening
   across the Rio Grande River, toward the I-35 corridor of Deep South
   Texas through 03-05Z, beneath modestly sheared, but weak, westerly
   deep-layer mean flow.

   ..Kerr.. 06/11/2025

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

   ATTN...WFO...CRP...EWX...

   LAT...LON   29999980 29819833 28089998 27420192 27770204 28570155
               28770054 29670010 29999980 

   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN