Valid 2026-09-08 01:00 UTC – 2026-09-08 12:00 UTC

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS OVER CENTRAL NORTH DAKOTA AND SOUTHEAST SOUTH DAKOTA

The threat for widely scattered severe storms capable of large hail and perhaps a tornado or two will continue over central North Dakota and southeast South Dakota into tonight. More isolated occurrences of large hail and severe wind gusts remain possible this evening over the central High Plains.

Northern Plains

Two separate severe thunderstorm regimes have evolved late this afternoon into evening. The first is over northwest into central ND, where widely scattered storms --including a supercell-- are ongoing ahead of a cold front pushing through western ND. The 00Z BIS sounding showed modestly steep low-level lapse rates and a moist boundary layer with MLCAPE CAPE of around 3000 J/kg. The corresponding wind profile was quite supportive of updraft rotation with effective SRH of around 300 m2/s2 and 60 kt of effective bulk shear, suggesting the supercell north of BIS will remain capable of large hail and a tornado or two for the next hour or two. Thereafter, increasing convective inhibition may result in the gradual weakening of the storms with a decreasing severe weather threat.

For additional near-term guidance on that regime, see recently issued MCD #2268.

The second thunderstorm regime is evolving across portions of northeast NE into southeast SD, near the intersection of a differential heating zone/outflow boundary and a pre-frontal trough. The boundary layer to the north of the baroclinic zone over southeast SD is slightly cooler with some convective inhibition noted in latest objective analysis fields. However, the presence of MLCAPE up to 2000-3000 J/kg, which coincides with 35-40 kt of deep-layer shear is supportive of supercells with the primary hazard being large hail, potentially in excess of two inches. The nocturnal strengthening of the low-level jet is resulting in enlarging low-level hodographs with effective SRH of 300-400+ m2/s2, per objective analysis. A tornado recently occurred with the ongoing storms near the NE-SD border with an additional tornado or two remaining possible this evening before convective inhibition increases further.

Mead · 09/08/2026