SPC MD 818

MD 0818 CONCERNING SEVERE POTENTIAL...WATCH UNLIKELY FOR PORTIONS OF CENTRAL AND SOUTH-CENTRAL TEXAS Mesoscale Discussion 0818 NWS Storm Prediction Center Norman OK 0534 PM CDT Thu May 21 2026 Areas affected...portions of central and south-central Texas Concerning...Severe potential...Watch unlikely Valid 212234Z - 220000Z Probability of Watch Issuance...20 percent SUMMARY...Some potential for damaging wind gusts and large hail will persist for at least another couple of hours. Watch issuance remains unlikely. DISCUSSION...Widely scattered thunderstorms remain ongoing in close proximity to a southward surging, convectively-reinforced surface boundary. Locally greater effective shear of 25-35 kts is supporting some updraft organization within this corridor, with marginal supercell structures evident in latest radar imagery in addition to a bowing segment/cluster noted in Gillespie/Llano Counties. Expectation is for this activity to gradually shift to the south and east in conjunction with the aforementioned surface boundary. Moderately steep mid-level lapse rates and MLCAPE of 1500-2500+ J/kg will continue to support a threat for isolated large hail with strong to occasionally damaging wind gusts also possible. Locally greater severe potential may accompany a bowing cluster as it progresses eastward toward the Austin, Texas, vicinity. A separate corridor of locally greater severe potential also appears possible farther west as southeastward-moving convection encounters greater instability (noted in latest objective analysis) within a zone of steeper low- and mid-level lapse rates in the vicinity of Del Rio. The overall severe risk is expected to remain limited in coverage/magnitude. Thus, watch issuance remains unlikely at this time. Trends will continue to be monitored, however. ..Chalmers/Thompson.. 05/21/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FWD...EWX...SJT... LAT...LON 30210162 30710146 30910112 30890049 30640002 30529947 30629900 31049860 31249826 31389792 31299757 31039732 30719728 30229732 29649760 29439815 29289890 29250003 29270057 29400106 29670140 29830153 30210162 MOST PROBABLE PEAK WIND GUST...55-70 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN Read more