ACUS11 KWNS 271845
SWOMCD
SPC MCD 271844=20
KYZ000-TNZ000-INZ000-ILZ000-MOZ000-ARZ000-272045-

Mesoscale Discussion 0571
NWS Storm Prediction Center Norman OK
0144 PM CDT Mon Apr 27 2026

Areas affected...Southern IL...southeast MO...western KY...western
TN...and northeast AR

Concerning...Severe potential...Tornado Watch likely=20

Valid 271844Z - 272045Z

Probability of Watch Issuance...95 percent

SUMMARY...The supercell tornado risk will increase through the
afternoon into this evening. A few strong-intense tornadoes will be
possible. A Tornado Watch is likely.

DISCUSSION...Visible satellite imagery shows increasingly agitated boundary-layer cumulus evolving in the open warm sector near the
confluence of the OH/MS Rivers and southward. Here, diurnal heating
of a moist air mass (upper 60s to lower 70s dewpoints) beneath steep
midlevel lapse rates (around 8.5 C/km per SGF 18Z sounding) is
yielding strong surface-based buoyancy. Over the next several hours, discrete/semi-discrete thunderstorms should develop within areas of differential heating and north/south-oriented confluence zones,
aided by an increasing low-level mass response accompanying a
deepening surface cyclone to the north. The strong buoyancy and
around 50 kt of effective shear will favor supercells, and modest
large-scale forcing for ascent and some lingering capping at the
base of the EML should favor a discrete/semi-discrete mode. Given a
50 kt southerly low-level jet and associated large clockwise-curved
hodographs (250-300+ m2/s2 effective SRH) -- strongest with
northward extent, several supercell tornadoes and very large
hail/damaging winds are expected. The best overlap of strongest
low-level shear and buoyancy is expected over southern IL, southeast
MO, and western KY, where a few strong-intense tornadoes are
possible.=20

A Tornado Watch issuance is likely.

..Weinman/Guyer.. 04/27/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5e1r_kJczXqAmFUelAWFP6dCMHsa5KVku_to5LMJTZeUfUDBpgdxJLIo7vhLJP_XR1xdCVhDj= vjtr-Ap9zbFreDhKlo$ for graphic product...

ATTN...WFO...OHX...PAH...MEG...LSX...LZK...SGF...

LAT...LON 37029096 37529027 37778971 37908922 37988848 37938773
37668737 37288722 36918728 36618745 36218761 35748784
35398820 35178865 35078922 35048991 35039057 35129110
35479158 35979157 36519131 37029096=20

MOST PROBABLE PEAK TORNADO INTENSITY...140-170 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN


=3D =3D =3D
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