Mesoscale Discussion 1873
NWS Storm Prediction Center Norman OK
1047 PM CDT Sat Aug 08 2026
Areas affected...Southern North Dakota into northeast South Dakota
and far western Minnesota
Concerning...Severe potential...Watch possible
Valid 090347Z - 090545Z
Probability of Watch Issuance...40 percent
SUMMARY...Elevated thunderstorms developing along the North
Dakota/South Dakota border may continue to intensify and grow
upscale over the coming hours. If upscale growth can occur, a more
pronounced severe risk may emerge and require watch issuance.
Convective trends are being monitored.
DISCUSSION...Deep convection has begun to emerge along the ND/SD
border over the past 30-45 minutes with additional towering, but
weaker, convection noted in GOES IR imagery over southern and
eastern ND. Similar to previous attempts at sustained deep
convection, this activity appears to largely be driven by increasing
isentropic ascent within the warm advection branch of a weak cyclone
over the western Dakotas - augmented by a slight uptick in the
nocturnal jet strength over the past hour (per regional VWPs). This
emerging convection resides on the northern periphery of a buoyancy
reservoir with MUCAPE values as high as 4000 J/kg analyzed
downstream into SD. Additionally, 50-60 knot effective bulk shear
was recently sampled by the 00 UTC BIS and ABR RAOBs, suggesting
that intensification/organization of this convection is likely.
Given the trends in IR imagery, adequate forcing for ascent, and
downstream environment, it appears possible that some severe threat
will emerge over the next few hours along the ND/SD border. Latest
runs of the RRFS appear to be capturing convective trends well and
suggest additional convection will manifest over the next 1-2 hours
before growing upscale. If/when this occurs, the potential for
severe hail and severe wind gusts will likely increase. Convective
trends are being monitored, and watch issuance may be required if
convective coverage increases.
..Moore/Mosier.. 08/09/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...MPX...FGF...FSD...ABR...BIS...
LAT...LON 44089833 45710129 46190136 46520111 46710048 46269615
45709598 45139615 44619650 44369697 44169761 44089833
MOST PROBABLE PEAK WIND GUST...55-70 MPH
MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN
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