Mesoscale Discussion 1121
NWS Storm Prediction Center Norman OK
1240 PM CDT Sat Jun 13 2026
Areas affected...portions of the mid-Mississippi and lower Ohio
Valleys
Concerning...Severe potential...Watch possible
Valid 131740Z - 131915Z
Probability of Watch Issuance...40 percent
SUMMARY...An ongoing convective cluster in southern Missouri has
exhibited some intensification over the past hour, with isolated
damaging wind gusts and large hail possible.
DISCUSSION...Latest GOES imagery and lightning data indicate that an
ongoing convective cluster in southern Missouri downstream of an MCV
over southeast Kansas has intensified some, with an uptick in
lightning and modest cloud top cooling noted over the past hour.
While denser cloud cover is present downstream of this cluster
across much of southeastern Missouri, clear conditions farther south
in northeast Arkansas and low-level warm, moist air advection are
contributing to a destabilizing air mass with minimal remaining
inhibition indicated by latest objective analysis and RAP forecast
soundings.
Latest high-res guidance continues to poorly capture this complex.
Thus, the exact evolution remains uncertain. However, guidance does
suggest that sufficient effective shear (25-30+ kts) will remain in
place owing, in part, to the presence of the upstream MCV (and
perhaps a second, weaker MCV over southern Missouri). Coupled with
the moderately unstable environment, it is possible that this
complex continues east-southeastward over the next couple of hours.
In this scenario, a greater threat for damaging wind gusts (and
perhaps an instance or two of large hail) may develop through the
afternoon should this cluster intensify. Trends are being monitored,
and a Severe Thunderstorm Watch may be needed pending further
intensification/persistence of this cluster.
..Chalmers/Mosier.. 06/13/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...PAH...MEG...LSX...LZK...SGF...
LAT...LON 37339130 37509096 37599042 37638986 37628952 37548922
37378899 37058872 36788864 36438866 36108891 35848933
35768969 35769008 35799057 35889100 36039147 36179174
36469199 36649199 36879188 36979178 37179155 37339130
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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