453 

ACUS11 KWNS 290803

SWOMCD

SPC MCD 290802 

SDZ000-NEZ000-291000-



Mesoscale Discussion 1374

NWS Storm Prediction Center Norman OK

0302 AM CDT Mon Jun 29 2026



Areas affected...much of central South Dakota



Concerning...Severe Thunderstorm Watch 412...



Valid 290802Z - 291000Z



The severe weather threat for Severe Thunderstorm Watch 412

continues.



SUMMARY...Storms over south-central South Dakota are expected to

become an intense complex over the next couple hours, producing

winds of 75-90 mph and large hail across central parts of the state.



DISCUSSION...Earlier supercells have merged near the cold front and

surface low over southwest SD, with recent radar trends indicating

the early stages of upscale growth into a compact but significantly

severe MCS. Aside from the supercell over Bennett County SD, radar

also shows a warm advection wing developing east/northeast of it,

with additional development south of this cell along the cold front.

This evolution is taking place near a substantial 850 mb theta-e

gradient, with MUCAPE up to 4000 J/kg along and south of the surge.



Given recent trends, strong instability and steep lapse rates aloft,

and a favorable low-level jet, confidence is increasing that this

complex will strengthen, and possible accelerate northeastward

through the morning hours. Additional watches may be required

downstream into more of northern/northeast SD and southeast ND as

the scenario evolves.



..Jewell.. 06/29/2026



...Please see www.spc.noaa.gov for graphic product...



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



LAT...LON   42900231 43320213 43610187 44000134 44560086 45220005

            45179925 44989881 44579880 43819925 43180022 42920144

            42760224 42900231 



MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH

MOST PROBABLE PEAK WIND GUST...75-90 MPH

MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN