ACUS11 KWNS 280218
SWOMCD
SPC MCD 280218=20
SDZ000-NEZ000-280345-

Mesoscale Discussion 1481
NWS Storm Prediction Center Norman OK
0918 PM CDT Fri Jun 27 2025

Areas affected...portions of central South Dakota

Concerning...Severe Thunderstorm Watch 469...

Valid 280218Z - 280345Z

The severe weather threat for Severe Thunderstorm Watch 469
continues.

SUMMARY...Damaging winds appear likely to continue this evening as a
couple of severe storm clusters spread eastward across WW469. A
local expansion may be needed as storms approach the eastern edge of
the watch.

DISCUSSION...As of 0210 UTC, regional radar imagery showed two
clusters of severe thunderstorms ongoing within WW469 across SD. The
northern most cluster (across parts of Carson, Ziebach and Dewey
Counties) has shown steady intensification over the last hour as it
has moved into large buoyancy (MLCAPE ~4000 J/kg). This
intensification trend should continue with the environment
downstream still very unstable and supportive of severe storms. As
low-level warm advection increases with the arrival of the low-level
jet, continual upscale growth is expected. Therefore, damaging gusts
are the most likely hazard.

Farther south, initial supercells have gradually coalesced into a
broader cluster roughly along I-90. An increase in forward speed and
recent wind gust to 71 mph suggests a stronger cold pool is becoming established. Similar to the northern cluster, a very unstable
environment remains in place, supportive of organized deep
convection. This should support a continued threat for damaging
winds and some hail as this storm cluster propagates east/southeast
this evening.

..Lyons.. 06/28/2025

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!5IJcFIKmF8ilbRY9QmWtq5xgIglV4TzFpTd01lkkUAfCYxb-aSgfQK1LYobfqQZlLjIo1weeu= ZwjRKThZOqMM7jm6Eg$ for graphic product...

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

LAT...LON 45909899 45889853 44639754 44539749 43749708 42949718
42849769 42819798 43139954 44110087 44770136 45820115
45909899=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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