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
Category: Watches, Warnings, Advisories, & Hazards