Mesoscale Discussion 0869
NWS Storm Prediction Center Norman OK
0748 PM CDT Tue May 26 2026
Areas affected...portions of south-central Texas
Concerning...Severe potential...Severe Thunderstorm Watch likely
Valid 270048Z - 270215Z
Probability of Watch Issuance...80 percent
SUMMARY...A developing, bowing MCS will transition eastward across
portions of south-central Texas this evening, with the potential for
severe to significant wind gusts and perhaps an embedded tornado or
two. Additional development may also occur later tonight along the
southern flank of this system and/or upstream of South Texas. A new
Severe Thunderstorm Watch will likely be needed in the next hour to
cover these threats.
DISCUSSION...Latest radar imagery from KDFX depicts the development
of a rear inflow jet within the northern portion of a linear MCS to
the southwest of San Antonio, Texas. This MCS is located along the
northern edge of a low-level instability gradient, with moderate to
strong buoyancy (2000-3000 J/kg MLCAPE) analyzed downstream across
south-central Texas. 35-40+ kts of effective shear and relatively
straight hodographs (as sampled by the 00z CRP observed sounding)
will favor the continued maintenance of this system into the
overnight hours as it tracks east-northeastward along the
instability gradient. Severe to significant severe wind gusts will
be the greatest threat with this system, but an embedded tornado
cannot be ruled out.
Farther east, a persistent, discrete supercell remains ongoing south
of San Antonio. It remains unclear how long this cell will persist,
but large hail, damaging wind gusts, and an isolated tornado remain
possible. Latest guidance also suggests that additional development
is possible along the trailing flank of this MCS and/or upstream of
South Texas during the overnight hours, with the potential for a
separate MCS/cluster to develop.
Given this severe potential, a new Severe Thunderstorm Watch is
likely in the next hour to cover these potential threats.
..Chalmers/Thompson.. 05/27/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...HGX...CRP...EWX...BRO...
LAT...LON 28050016 28520013 29259997 29539976 29779917 30029787
30059751 29919720 29549692 29199681 28299683 27809708
27439730 27249761 27189864 27219928 27339955 27990013
28050016
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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