ACUS11 KWNS 272207
SWOMCD
SPC MCD 272207=20
SDZ000-MTZ000-272330-

Mesoscale Discussion 1478
NWS Storm Prediction Center Norman OK
0507 PM CDT Fri Jun 27 2025

Areas affected...portions of northwest and north-central South
Dakota

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

Valid 272207Z - 272330Z

Probability of Watch Issuance...40 percent

SUMMARY...Initial high-based convection across northeast WY may
persist and intensify across northwest SD this afternoon/evening.
Confidence in storm evolution is low, but a mix of supercells and
clusters could support a hail and wind risk. Conditions are being
monitored for possible WW issuance.

DISCUSSION...As of 22 UTC, regional observations showed a complex
surface pattern evolving across the central and northern High
Plains. Several thunderstorms have initiated along a wind shift
across the higher terrain of northeastern WY as ascent from a
mid-level shortwave trough has moved overhead. While initially
high-based, these storms are approaching the western edge of a very
unstable warm sector with deep surface moisture concentrated along
the northern periphery of the Black Hills. Moderate vertical shear
is also present from the UDX VAD sufficient for supercells.

Recent CAM guidance and observational trends suggest these storms
may continue to intensify as they move eastward. However, there
remains considerable uncertainty on the converge of the stronger
storms. The large buoyancy and supportive shear would favor a risk
for large to very large hail and damaging gusts. The presence of
multiple surface boundaries could also support a brief tornado with
any of the stronger rotating storms. Given the increasing severe
potential, convective trends will continue to be monitored for WW
issuance across parts of northwest and north-central SD.

..Lyons/Guyer.. 06/27/2025

...Please see https://urldefense.com/v3/__http://www.spc.noaa.gov__;!!DZ3fj= g!_S7gTjSuRLZicRX7iYPfDfIoDYWjKirBRVwtomdNFaqp_68__bwV7B_0qi5gkx763fBplSVRp= jTlG1knagc2g_a7v04$ for graphic product...

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

LAT...LON 44190288 44310121 45140057 45920066 45920382 45240406
44620386 44190299 44190288=20

MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
MOST PROBABLE PEAK WIND GUST...65-80 MPH
MOST PROBABLE PEAK HAIL SIZE...2.75-4.25 IN


=3D =3D =3D
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