ACUS11 KWNS 271532
SWOMCD
SPC MCD 271531=20
INZ000-KYZ000-ILZ000-271730-

Mesoscale Discussion 0567
NWS Storm Prediction Center Norman OK
1031 AM CDT Mon Apr 27 2026

Areas affected...Central and southern Illinois into western Indiana

Concerning...Severe Thunderstorm Watch 158...

Valid 271531Z - 271730Z

The severe weather threat for Severe Thunderstorm Watch 158
continues.

SUMMARY...The threat for large hail and locally damaging wind gusts
will continue with ongoing storms this morning. The severe weather
threat may spread into western parts of Indiana by 17z, potentially
requiring the issuance of an additional Severe Thunderstorm Watch.

DISCUSSION...As of 15z, mosaic radar data showed an elevated bowing
segment with an embedded book-end vortex extending from around
Peoria to northeast of Litchfield in west-central IL. Additional,
elevated storms were also observed within an enhanced,
warm-advection wing preceding the bow across portions of central and
southern IL.=20

The ongoing convection is occurring to the northeast of a
north-northwest to south-southeast oriented warm front approaching
the MS River. Strong moisture and heat fluxes occurring along a
40-50+ kt low-level jet (per current KILX VWP) is supporting upwards
of 1000-1500 J/kg MUCAPE based on RAP forecast soundings. The
presence of 50-55 kt effective bulk shear will continue to support
organized storm modes such as supercells and bowing structures with
the primary hazard being large hail. Hail sizes should largely be
limited to less than 2" diameter due to relatively poor mid-level
lapse rates in place across the region. Locally damaging wind gusts
remain possible with any stronger downdrafts that can penetrate the near-surface inversion.

Short-term model guidance suggests the ongoing convective regime
will spread east of Severe Thunderstorm Watch 158 into western
Indiana by about 17z. An additional downstream watch may become
necessary prior to that time.

..Mead.. 04/27/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!98TmG3Jr8x1MaQzAC-VgAl2Ztu3vKgyQgsylqcOahMdHdmU1d8svLJYXco5TQ5Dp6nXad4W1U= aNCNYovKraiD5jRSXk$ for graphic product...

ATTN...WFO...IND...PAH...LOT...ILX...LSX...

LAT...LON 40008997 40758986 40788813 40478720 39088697 37778781
37878955 39239004 40008997=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN


=3D =3D =3D
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