ND/SD Border Supercells Prime for 90 MPH Winds, Baseball-Size Hail — SevereWX

Isolated thunderstorms are firing along a southeastward-moving cold front in portions of southern North Dakota and northern South Dakota, showing signs of rapid intensification into high-based supercells.

As of late afternoon on July 19, 2026, cumulus towers over far southwestern ND and northwestern SD have gained vertical depth, with storms already popping in Perkins and Meade Counties, SD. Steep lapse rates, 30 knots of effective shear, and elongating hodographs from strengthening upper-level flow set the stage for splitting supercells producing large hail—potentially 2-3.5 inches—and damaging outflows to 80+ mph.

Expect efficient cold pool formation leading to upscale growth into clusters as these storms push eastward through evening. The primary risks: severe wind gusts peaking at 75-90 mph and significant hail events.

SPC's Mesoscale Discussion 1663 tags an 80% probability for a Severe Thunderstorm Watch, underscoring the setup's potency. This activity fills a gap in today's slight risk outlook for the northern Plains.

Peak Threats:

Residents from Bismarck south to Rapid City should monitor radar closely as storms develop. Have a severe weather plan ready—seek shelter if warnings issue. Stay tuned to SevereWX.net for updates.