Mesoscale Discussion 2326 NWS Storm Prediction Center Norman OK 0348 PM CDT Wed Sep 23 2026 Areas affected...parts of southwestern North Dakota and adjacent portions of southeastern Montana and northwestern South Dakota Concerning...Severe potential...Watch unlikely Valid 232048Z - 232245Z Probability of Watch Issuance...5 percent SUMMARY...Isolated strong thunderstorm development posing at least a risk for severe hail appears increasingly probable by 4-6 PM MDT. This may be maintained for a couple of hours late this afternoon into evening. Although this is still not anticipated to require a severe weather watch, trends will be monitored. DISCUSSION...Stronger boundary-layer warming and deeper mixing has become focused near a weak surface low across the southeastern Montana/western Dakotas border vicinity, with some north-northeastward development still possible through late afternoon. Near the interface of this environment, and a narrow corridor of better low-level moisture return to the north/east, it appears that boundary-layer destabilization may maximize around the Dickinson, ND vicinity by 22-00Z. Aided by lift associated with a corresponding focused area of stronger low-level warm advection, as low-amplitude mid-level troughing continues to overspread the region, it appears that thunderstorms will initiate as remaining inhibition erodes. Near and just to the northwest of a strong southwesterly mid/upper jet (including speeds on the order of 40-70 kt in the 500-700 mb layer), updraft inflow of boundary-layer air characterized by CAPE up to 1000+ J/kg may support an evolving supercell structure. As this tends to propagate eastward, or east-southeastward, it may pose primarily a risk for severe hail, with perhaps some potential for locally damaging surface gusts and/or a brief tornado, for at least a couple of hours late this afternoon into evening. ..Kerr/Mosier.. 09/23/2026 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...ABR...BIS...UNR...GGW... LAT...LON 47460273 46080146 45570280 46370359 47070444 47460273 MOST PROBABLE PEAK TORNADO INTENSITY...UP TO 90 MPH MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH MOST PROBABLE PEAK HAIL SIZE...1.00-1.75 IN
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