ACUS11 KWNS 281926
SWOMCD
SPC MCD 281926=20
OKZ000-TXZ000-282100-

Mesoscale Discussion 0599
NWS Storm Prediction Center Norman OK
0226 PM CDT Tue Apr 28 2026

Areas affected...portions of northern Texas into south-central
Oklahoma

Concerning...Tornado Watch 171...

Valid 281926Z - 282100Z

The severe weather threat for Tornado Watch 171 continues.

SUMMARY...The threat for all severe hazards, with very large to
giant hail the primary risk, is increasing across portions of
Tornado Watch 171.

DISCUSSION...Supercell development is ongoing along a surface
boundary across portions of northwest Texas/south-central Oklahoma,
with recent reports of golf ball size hail in Archer County, Texas.
The environment ahead of this boundary is strongly unstable, with
latest mesoanalysis depicting 3000-4000+ J/kg MLCAPE underlying
strong deep-layer flow (as sampled by regional VWPs) and 50-60+ kts
of effective bulk shear. The greatest threat with these storms is
expected to be very large to giant hail to 3-4"+ in diameter owing
to steep mid-level lapse rates, strong buoyancy within the hail
growth zone (1000+ J/kg), and elongated hodographs. While the
tornado threat may remain somewhat limited owing to modest low-level
shear, tornado potential will likely be locally maximized with any
supercells that can favorably interact with a modifying surface
outflow boundary analyzed near the Red River Valley. The greatest
near-term potential for a tornado may exist with the ongoing
supercell in Clay County, Texas given its proximity to the
aforementioned outflow boundary, with recent WoFS runs depicting
greater tornado probabilities with this storm over the next 1-2
hours.

With time, expectation is for some clustering/upscale growth of
supercells to occur as storms progress southeastward, which will
favor an increase in the threat for damaging/severe winds and the
potential for destructive, wind-driven hail.

..Chalmers.. 04/28/2026

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_vrBOatXpFGUrjgd0GLQFNjLzzcKfJO-TFAF7mjtEPRXs8wGRM8RZcgutshkoUQnkUNMsjfJY= 19XoaAVB6D7EHC11jQ$ for graphic product...

ATTN...WFO...TSA...FWD...OUN...SJT...

LAT...LON 34149815 34399777 34839707 35029610 34619548 33699550
33129618 32859688 32669782 32599884 32829924 33029919
33469885 33759862 34149815=20

MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...4.00+ IN


=3D =3D =3D
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