Overview
- The Storm Prediction Center placed parts of eastern South Dakota, southwest Minnesota and northwest Iowa at Enhanced Risk and multiple mesoscale discussions warned of imminent watches after storms produced measured gusts including 72 mph near Mason City and reports up to about 90 mph.
- Very high instability with MLCAPE commonly 2000–3500 J/kg and 35–50 kt mid‑level flow supported discrete supercells that in many cases upscaled into bowing clusters and compact MCSs that produced the strongest wind swaths.
- SPC used mesoscale discussions to assign high watch probabilities, including a 95 percent probability for corridors moving from eastern South Dakota into Minnesota, and coordinated watch issuance with local National Weather Service offices.
- As of early July 4, many MCS segments are weakening as they move into more stable air, but localized severe wind gusts and isolated hail remain possible where short‑term redevelopment occurs along surging outflow boundaries.
- Strong gusts pose direct local threats to roofs, siding, trees and outdoor events, and forecasters say the timing and placement of outflow‑driven redevelopment will determine which communities see renewed severe impacts.