Mesoscale Discussion 2047
NWS Storm Prediction Center Norman OK
0852 PM CDT Wed Aug 19 2026
Areas affected...portions of southeastern Missouri into southern
Illinois...far northern Arkansas...western Kentucky...far
northwestern Tennessee
Concerning...Severe potential...Watch possible
Valid 200152Z - 200315Z
Probability of Watch Issuance...60 percent
SUMMARY...The risk for severe hail is increasing, with some chance
also for a few damaging gusts or a tornado. Regarding the need for a
WW issuance, convective trends will continue to be monitored for
storms increasing in coverage and intensity.
DISCUSSION...Convective initiation is underway across southern MO
into far northern AR, likely driven by convergence along the
terminus of an intensifying low-level jet. These storms are expected
to be largely elevated in nature per latest RAP forecast soundings.
Nonetheless, 7-8 C/km mid-level lapse rates above the stabilizing
boundary layer (per SGF and BNA 00Z observed soundings) is
contributing to 2000-3000 J/kg MUCAPE, as well as around 50 kts of
unidirectional (westerly) speed shear. Should a stronger updraft
intensity and become sustained, severe hail may occur. Surface-based
convection appears less likely, but should this occur, a supercell
may develop and pose the risk for damaging gusts or a tornado.
At the moment, severe potential remains in question given the
anticipated elevated nature of the convection and relatively weak
deep-layer ascent. Furthermore, the latest high-resolution guidance
has not shown appreciable consistency in the placement, timing,
evolution, or morphology of anticipated convection. Therefore,
convective trends will continue to be closely monitored through the
evening for WW issuance potential.
..Squitieri/Guyer.. 08/20/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...IND...PAH...ILX...MEG...LSX...SGF...
LAT...LON 37439237 38349183 38589096 38699008 38808845 38568726
37998709 36988744 36688813 36558952 36609064 36809225
37439237
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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