Overview
- Multiple SPC mesoscale discussions and radar analyses reported supercells over central and eastern Colorado producing very large hail, with MRMS data suggesting some stones reached 2–4 inches in diameter during Wednesday night.
- The SPC confirmed at least one brief tornado in northeastern Colorado and maintained active tornado and severe thunderstorm watches for the High Plains as storms continued to produce pockets of severe hail and damaging gusts.
- Forecasters warned that ongoing cold‑pool mergers could allow the storms to upscale into a mesoscale convective system, which would concentrate severe straight‑line winds and could produce gusts in excess of 75 mph in parts of northeastern Colorado, southwestern Nebraska and northwest Kansas.
- As the convective corridor shifts east and weakens overnight, local forecast offices and TV meteorologists flagged the next threats as heavy downpours with 1–3 inches possible, localized flash flooding in low‑lying and urban areas, and smoky skies in southern Colorado from western wildfires.
- Operational models and SPC analyses attribute the outbreak to very high instability, strong deep‑layer shear and low‑level moisture transport, and they caution residents to expect more rounds of severe storms this week followed by a late‑week heat surge in the Midwest and Great Lakes.