ACUS11 KWNS 212316
SWOMCD
SPC MCD 212316=20
KSZ000-COZ000-NEZ000-220115-

Mesoscale Discussion 0821
NWS Storm Prediction Center Norman OK
0616 PM CDT Thu May 21 2026

Areas affected...parts of southwestern Nebraska...northeast and east
central Colorado...adjacent northwestern Kansas

Concerning...Severe Thunderstorm Watch 239...

Valid 212316Z - 220115Z

The severe weather threat for Severe Thunderstorm Watch 239
continues.

SUMMARY...Isolated to widely scattered supercell development is
likely to persist through 6-8 PM MDT, accompanied by the risk for
large hail and perhaps some increase in potential for a tornado near
the Colorado/Kansas state border to the west-northwest of Goodland.

DISCUSSION...Isolated thunderstorm development has undergone notable intensification the past few hours, aided by destabilization
associated with continued boundary-layer warming and moistening.=20
This appears to have contributed to CAPE on the order of 1000-1500,
in the presence of strong westerly deep-layer shear, though with
mean ambient winds on the order of 20-30 kt, due to the veering of
winds with height.

Of the ongoing storms, the prominent supercell to the
north-northeast of Limon CO appears to have the longest access to
unstable inflow as it propagates eastward toward the Kansas state
border to the west-northwest of Goodland through 7-8 PM MDT. It
appears that this may coincide with enlarging low-level hodographs
accompanying strengthening east-southeasterly 850 mb flow, which may
promote some further increase in potential for a tornado or two.

..Kerr.. 05/21/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!-P2DINRdRlZYUSMGdMM6-3tEiKF4NKbKqh2OVFNh-2ySKxDQS5rGlNgF834RSMcq8c22zPEQ1= CKY0h8KumEjwmmA38I$ for graphic product...

ATTN...WFO...GLD...BOU...CYS...

LAT...LON 39890379 40800380 41420371 40840280 39750194 39040262
39020312 39380365 39890379=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


=3D =3D =3D
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