ACUS11 KWNS 171743
SWOMCD
SPC MCD 171742=20
MOZ000-KSZ000-OKZ000-NEZ000-172015-

Mesoscale Discussion 0474
NWS Storm Prediction Center Norman OK
1242 PM CDT Fri Apr 17 2026

Areas affected...portions of the southern/central Great Plains into
the mid-Missouri Valley

Concerning...Severe potential...Watch likely=20

Valid 171742Z - 172015Z

Probability of Watch Issuance...95 percent

SUMMARY...Numerous severe thunderstorms are expected to form
along/ahead of a cold front and dryline from northern Missouri
southwestward into northwestern Oklahoma this afternoon. Storms will
pose a threat for all hazards, including hail to 3-3.5+ inches in
diameter, very strong wind gusts of 60-80+ mph, and a couple of
tornadoes (perhaps strong). Watch issuance will be needed in the
next 1-2 hours.

DISCUSSION...Latest mesoanalysis depicts a strongly unstable air
mass in place ahead of a triple point over northwestern Oklahoma and
the associated cold front/dryline. Temperatures in the upper-70s F
and dewpoints in the mid/upper-60s are contributing to strong
instability of 2000-3000+ J/kg MLCAPE across the region per latest mesoanalysis. Low-level convergence is forecast to lead to
convection initiation near the triple point and along the cold
front/prefrontal confluence zone through the afternoon. Strong
southwesterly flow (50+ kts at 4-5 km AGL per regional VWPs) is
contributing to effective bulk shear of 40-50 kts (locally greater
near the triple point), which will support supercells with initial
storm formation. Steep mid-level lapse rates (as sampled by the 12z
OUN/TOP/SGF soundings and recent ACARS profiles), elongated
hodographs, and ample buoyancy within the hail growth zone will
support the potential for hail of 3-3.5+ inches in diameter. Strong
downdrafts (with wind gusts up to 60-80 mph) are also possible given
the presence of some drier mid-level air.

The tornado threat remains more uncertain as deep-layer flow is
largely oriented parallel to the cold front, which may yield complex
storm mode/interactions. Given the potential for supercellular mode
and storm/outflow interactions, at least some potential for a couple
of tornadoes (perhaps strong) appears to exist, however. This
appears most likely with any supercell that is able to remain more
discrete into the evening hours when a strengthening nocturnal
low-level jet will yield increasingly curved low-level hodographs.
Trends will continue to be monitored, and a tornado watch will be
needed within the next 1-2 hours to cover these threats.

With time, the development of a forward-propagating MCS is
anticipated across much of this area, with an accompanying
transition towards severe wind gusts (80+ mph wind gusts possible)
and perhaps embedded tornadoes as the primary threats.

..Chalmers/Mosier.. 04/17/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!6ycZC27m3MMt2M9eZNPGvbpNQlPqJKUwQVG-ZCLNd7S79u53mg4LRgilgXdIsWQkYnom6jM0V= lfsjmOakV092-fftcQ$ for graphic product...

ATTN...WFO...SGF...EAX...TSA...OAX...TOP...ICT...OUN...DDC...

LAT...LON 36559959 37359896 38879741 40089628 40419548 40519443
40279381 39679370 38659397 37659462 36669558 35639699
35079813 34999904 35509967 36559959=20

MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH
MOST PROBABLE PEAK WIND GUST...75-90 MPH
MOST PROBABLE PEAK HAIL SIZE...2.75-4.25 IN


=3D =3D =3D
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