ACUS11 KWNS 281947
SWOMCD
SPC MCD 281947=20
SDZ000-NEZ000-282145-

Mesoscale Discussion 1824
NWS Storm Prediction Center Norman OK
0247 PM CDT Mon Jul 28 2025

Areas affected...parts of south central and southeastern South Dakota...adjacent north central Nebraska

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

Valid 281947Z - 282145Z

Probability of Watch Issuance...60 percent

SUMMARY...Scattered, intensifying thunderstorm development, posing a
risk for a few strong downbursts and perhaps some hail, appears
possible by 4-6 PM CDT. Timing of a potential severe weather watch
issuance remains unclear, but trends are being monitored for this
possibility.

DISCUSSION...A surface cold front, now advancing south of Pierre,
Philip and Rapid City is becoming better defined, with strengthening differential heating along and ahead of it, centered near the
western South Dakota/Nebraska state border northeastward across the
Winner toward Huron vicinities. While temperatures are approaching
100 F within the corridor of stronger boundary-layer heating,
surface dew points have been slower to mix below 70F, and through
the 60s F, than suggested by model forecast soundings at Winner and
Valentine. Even so, latest objective analysis suggests that the
pre- and post-cold frontal boundary layer remains strongly capped
beneath the warm and elevated mixed-layer air as far north as the
North/South Dakota state border vicinity.

Mid/upper support for sustained boundary-layer based convection
anytime soon remains unclear, although it appears possible that a
subtle perturbation progressing across and east-northeast of the
Black Hills is contributing to ongoing attempts at convective
development. It appears more probable that with further insolation,
continued heating and deeper mixing within the pre-frontal
boundary-layer may eventually support intensifying, high-based
thunderstorm development late this afternoon. In the presence of
strong deep-layer shear, this activity could pose a risk for severe
hail and increasing potential for strong downbursts into early
evening.

..Kerr/Thompson.. 07/28/2025

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!8zimaT4Bxu_WSEIFvQreiWRCah51JFUvZmMeP9qZ3z-zhg_VizGGR9BPN4lIDKTkJJwxx4ssE= uak9h1XzESqTbhFA1E$ for graphic product...

ATTN...WFO...FSD...ABR...LBF...UNR...

LAT...LON 43370091 44049966 44449790 43689659 43239776 42699886
42500075 43370091=20

MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 95 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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