SPC Keeps Multiple Severe Thunderstorm Watches Over Central U.S.

Overview

• SPC maintained and adjusted several active severe‑storm watches on Monday, June 1, tracking storms from eastern Kansas into western Missouri and across parts of the High Plains.
• The primary hazards cited by SPC were very large and large hail plus damaging straight‑line winds with isolated brief tornadoes possible where discrete supercells persisted.
• Objective analyses showed extreme instability with mixed‑layer CAPE often above 2,500 to 4,500 J/kg and deep‑layer shear around 35–50 knots, conditions that favor organized supercells capable of very large hail.
• Forecasters repeatedly noted that initially discrete hail‑producing supercells often merged into clusters or mesoscale convective systems, shifting the main threat toward damaging winds and changing the need for new or expanded watches.
• SPC used mesoscale discussions and quantified watch probabilities — including an 80 percent likelihood for a watch in eastern Kansas/western Missouri — and said weakening MCSs in the Mid‑Mississippi/Ohio Valley have lowered short‑term downstream watch needs while crews stand ready to act if storms initiate or grow upscale.