ZCZC SPCSWOMCD ALL ACUS11 KWNS 260639 SPC MCD 260639 TXZ000-260845- Mesoscale Discussion 1711 NWS Storm Prediction Center Norman OK 0139 AM CDT Fri Jul 26 2024 Areas affected...Upper TX Coastal Plain Concerning...Severe potential...Watch unlikely Valid 260639Z - 260845Z Probability of Watch Issuance...5 percent SUMMARY...Potential exists for a brief tornado through about dawn with slow-moving, isolated thunderstorms over the Upper Texas Gulf Coastal Plain. The limited spatiotemporal extent and low probability of occurrence should preclude a watch issuance. DISCUSSION...Persistent low-level warm theta-e advection has supported scattered low-topped convection from the Mid to Upper TX Gulf Coast into southeast TX. One cell near the north end of Galveston Bay has recently deepened into a slow-moving thunderstorm, drifting northeast at 10 kts. HGX VWP has sampled 0-1 km shear around 20 kts with surface southeasterlies veering to the south at 1 km. The enhancement to hodograph curvature is nearly exclusively in the low-levels, with a nearly unidirectional southwesterly wind profile above 2 km. As such, transient supercell structure may occur. This would seemingly be most probable within this portion of the warm-advection regime given a relatively larger thermal gradient, inferred by surface temperatures in the low 80s over Galveston Island to low to mid 70s with northern extent in southeast TX. The concern in this scenario is if the transient supercell structure can briefly intensify to produce a tornado, although a downburst or two is also possible. With time, enhanced low-level flow should subside/shift northward, and likely curtail the threat after daybreak. See WPC MPD 0731 for information on the heavy rain/flash flooding potential. ..Grams/Guyer.. 07/26/2024 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...LCH...HGX... LAT...LON 30399509 30739474 30639410 30099403 29619426 29269482 29209534 30199520 30399509 NNNN