Mesoscale Discussion 1738
NWS Storm Prediction Center Norman OK
0241 PM CDT Sun Jul 20 2025
Areas affected...south-central South Dakota across western Nebraska
and toward northwest Kansas
Concerning...Severe potential...Watch possible
Valid 201941Z - 202215Z
Probability of Watch Issuance...60 percent
SUMMARY...Scattered severe storms appear likely later this afternoon
from south-central SD across west-central NE and toward northwest
KS. A few cells may produce large hail, with locally damaging gusts.
A tornado is possible over southern SD into far northern NE after
23Z. A portion of the area may require a watch.
DISCUSSION...Surface map shows low pressure extending from southwest
SD across western NE and into the CO/KS border area, with strong
heating. This trough will continue to deepen, and sufficient
convergence within the uncapped air mass should allow for widely
scattered storms to develop late this afternoon.
Of particular note is the warm front area which currently curls
northwestward out of northern NE and into south-central SD. Here,
heating is occurring on the cool side of the boundary, where
dewpoints remain above 70 F and low-level shear is enhanced. Any
supercell that develops here, most likely after 23Z, could be
tornadic at times, and produce very large hail as it proceeds
southeastward, aided by a modest evening low-level jet.
Farther south into the deeper/heated air mass, higher based storms
are expected, and overall shear is weaker as well. However, steep
lapse rates will favor locally severe gusts, and even some hail in
the early and robust formation stages.
..Jewell/Smith.. 07/20/2025
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...ABR...LBF...UNR...GLD...BOU...
LAT...LON 42940011 41680031 40480068 39280162 39210233 40430230
41640217 42900209 43440215 43740228 44020246 44250227
44360152 44250113 43880051 42940011
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
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