Mesoscale Discussion 0755
NWS Storm Prediction Center Norman OK
0338 PM CDT Sun May 17 2026
Areas affected...portions of the central Great Plains
Concerning...Severe potential...Watch possible
Valid 172038Z - 172245Z
Probability of Watch Issuance...40 percent
SUMMARY...Isolated thunderstorm development is possible across the
eastern Texas Panhandle, northwest Oklahoma, and south-central
Kansas along a dryline this evening, with a conditional threat for
all severe hazards. Trends are being monitored for possible watch
issuance.
DISCUSSION...Latest surface analysis depicts a surface low near the
Kansas/Nebraska border with a trailing dryline extending
south-southwestward through central Kansas into northwest Oklahoma
and the Texas Panhandle, with recent visible satellite imagery
depicting sporadic Cu developing along this boundary. East of the
dryline, steep mid-level lapse rates (8.5+ C/km) and rich low-level
moisture (as sampled by the 18z OUN/DDC observed soundings) are
supporting strong instability, with 2500-3500+ J/kg MLCAPE analyzed
via latest mesoanalysis.
Notable uncertainty remains regarding the development of sustained
thunderstorms owing to strong capping sampled by the 18z OUN
sounding and nebulous upper-level forcing. While effective shear is
forecast to remain modest (generally 25-35 kts), a conditional
severe threat exists should a storm develop. The aforementioned
steep mid-level lapse rates and modest effective shear would support
a threat for large hail, with a strengthening southerly low-level
jet also promoting an increasing tornado threat this evening with
any developing/persistent supercells. Some high-res guidance also
suggests some potential for the development of a linear segment,
which would favor a greater risk for severe/damaging wind gusts.
Trends will continue to be monitored, and watch issuance could be
needed should convective initiation appear likely/imminent given
this conditional severe threat.
..Chalmers/Mosier.. 05/17/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ICT...OUN...DDC...AMA...
LAT...LON 35550050 36979991 38119945 38459914 38499853 38209813
37459785 36749802 36229829 35609888 34909979 34790007
34770041 34910059 35230062 35550050
MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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