Subj : MESO: Mesoscale Discussion 1798
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sat Jul 26 2025 23:42:32

ACUS11 KWNS 262342
SWOMCD
SPC MCD 262341=20
SDZ000-270045-

Mesoscale Discussion 1798
NWS Storm Prediction Center Norman OK
0641 PM CDT Sat Jul 26 2025

Areas affected...portions of central South Dakota

Concerning...Severe potential...Watch possible=20

Valid 262341Z - 270045Z

Probability of Watch Issuance...40 percent

SUMMARY...Splitting supercells should persist for at least a few
more hours in a localized but very favorable environment for severe
hazards, including very large hail or a tornado.

DISCUSSION...A pair of splitting supercells continue to mature over
portions of central SD near the surface low, where large amounts of
low-level vertical-oriented vorticity resides. Furthermore, extreme
instability precedes the storms, with the latest mesoanalysis
showing over 5000 J/kg MLCAPE in place. Finally, with 40 kts of
effective bulk shear overspreading this extreme instability, and
given 200 m2/s2 effective SRH across northern SD, it seems plausible
that a localized but potentially significant-severe threat may
accompany these storms over the next few hours. 2+ inch diameter
hail will probably be the main hazard with these storms, though a
landspout/supercell hybrid tornado could accompany the southern
supercell if it can successfully stretch the vertical vorticity in
place.

It is unclear if a WW issuance is needed at this point given how
sparse these storms are. However, upscale-growing storms may
approach the Dakotas this evening into the overnight, where greater
coverage will exist, and when a WW issuance may be necessary.

...Squitieri/Mosier.. 07/26/2025

....Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj=
g!-3MhP9dMRvHi6Q6IcDMcsss8O5CGcj0e7u7MSxAhKW2MIx7Cw6wBWr24IKv-oPdtSFXP8oB2R=
xG8AgL0alcFFYS6PYE$  for graphic product...

ATTN...WFO...ABR...UNR...

LAT...LON   44610124 45060115 45390099 45560078 45560039 45330022
            45080015 44800017 44590053 44550098 44610124=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN


=3D =3D =3D
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