Mesoscale Discussion 1236
NWS Storm Prediction Center Norman OK
0612 PM CDT Sun Jun 21 2026
Areas affected...northwest Oklahoma
Concerning...Severe potential...Watch possible
Valid 212312Z - 220115Z
Probability of Watch Issuance...40 percent
SUMMARY...Thunderstorms may develop across the area this evening.
Should they develop, the overall environment will support large hail
and damaging winds and a watch would become necessary. The area will
be monitored closely for thunderstorm potential and subsequent need
for a watch.
DISCUSSION...A remnant outflow boundary is located across northern
Oklahoma, stretching from near Woodward, OK, east toward Ponca City,
OK. The cumulus field along this boundary has become increasingly
agitated over the last hour, with clumping of the cumulus across
Woodward County, OK, noted.
Thunderstorm development is uncertain this afternoon, with the
high-resolution numerical guidance oscillating back and forth
between solutions with initiation and solutions without initiation.
(The most recent runs of the HRRR -- 21 & 22 UTC -- do initiate this
evening across northwest Oklahoma.)
Should storms develop, the overall thermodynamic environment across
the area is very unstable with MUCAPE values between 3000-4000 J/kg,
with forecast soundings suggesting the maximum lapse rates in the
2-6 kilometer layer achieving 8 C/km. Kinematically, the environment
is strongly sheared, with effective-layer shear around 40 knots.
Given this environment, an evolution toward supercells would be
possible with any thunderstorm. Relatively straight hodographs would
suggest that splitting supercells would be possible, with large hail
and damaging winds possible (RAP profiles suggest DCAPE ~1500 J/kg).
Low-level flow is relatively weak across the area, so the overall
tornado threat should be somewhat limited. However, with the
potential for supercellular mode, strong instability, and a surface
boundary, the tornado potential is non-negligible.
Should confidence increase that initiation is underway or imminent,
a watch may become necessary across portions of northwest Oklahoma.
Regardless of whether thunderstorms initiate this afternoon/evening,
a more appreciable threat for severe thunderstorms is likely to
evolve later tonight with a southeast-advancing MCS moving into the
region from Kansas.
..Marsh/Smith.. 06/21/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...OUN...
LAT...LON 35499970 36169993 36659978 36919931 36979864 36949811
36779765 36669739 36389730 36099731 35709784 35549846
35419897 35499970
MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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