RSS Mesoscale Discussions from Storm Prediction Center
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0812 PM CDT Sun Jun 21 2026
Valid 220100Z - 221200Z
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS FOR SOUTHWEST
KS INTO NORTH-CENTRAL OK...
...SUMMARY...
Tornadoes (possibly strong) and damaging winds remain possible this
evening into parts of the Mississippi and Ohio Valleys. A swath of
severe gusts (possibly greater than 75 mph) appears possible later
tonight from southwest Kansas into central Oklahoma.
...Mid MS Valley into the Ohio Valley...
An MCV moving across IN will eventually encounter weaker low-level
moisture and instability with eastward extent. However, a long-lived
storm cluster may continue eastward toward parts of southwest OH and
eastern KY, before a definitive weakening trend occurs. Damaging
wind and embedded tornadoes will remain possible with the primary
storm cluster until weakening occurs. Semi-discrete cells and small
clusters trailing the MCV will also continue to pose a threat of
tornadoes (possibly strong) and damaging winds through the evening,
within a moist and favorably sheared environment. See MCD 1237 for
more information.
...Central High Plains into OK and southern MO...
Widely scattered storm development is underway near a surface
boundary draped from northwest OK into southeast KS/southwest MO.
While large-scale forcing is generally modest at best, MLCAPE of
2500-4000 J/kg and effective shear of 40+ kt are conditionally quite
favorable for organized storms. A few supercells may persist along
the front through the evening, with a threat of large to very large
hail and localized severe gusts. Also, while low-level flow is weak,
vorticity and backed surface winds near the boundary could support
some tornado potential, if a robust supercell can become
established.
Farther northwest, a supercell cluster is ongoing across western KS
this evening. This cluster will continue to pose a threat of large
to very large hail, severe gusts, and possibly a tornado through the
evening. See MCD 1239 for more information regarding the short-term
threat.
Short-term guidance (notably the HRRR and RRFS) suggests that this
cluster will continue to grow upscale, and potentially evolve into
an MCS that will move southeastward across southwest KS into
northwest and central OK, with threat of severe gusts (potentially
above 75 mph) through the overnight hours. This evolution appears
plausible, if evening convection across northwest OK is not too
disruptive to the environment. Given the very favorable midlevel
lapse rates on the 00Z DDC and OUN soundings, rich moisture, and
strong instability and deep-layer shear, a 30%/CIG1 wind area was
added from southwest KS into central OK.
..Dean.. 06/22/2026
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