Supercell Morphs into Wind-Lashed Bow Echo Storming Eastern IL-IN Border — SevereWX

A supercell thunderstorm over northeast Illinois is rapidly evolving into a powerful bow echo, packing radar-indicated 80-knot winds just above the surface. This system is surging southeastward at 40-45 mph into far eastern Illinois and northern/central Indiana through early evening.

Fueled by extreme instability (3000-4000 J/kg MLCAPE) and robust wind shear (45+ kt), the bow echo promises a swath of damaging winds up to 80 mph, with isolated large hail (1-1.75 inches) and a tornado or two possible. SPC Mesoscale Discussion 1764 flags a 95% chance of a new watch downstream from Watch 520, highlighting the primed environment ahead.

Peak threats include:

Storms could impact areas from near the IL-IN line through central IN this afternoon. Residents near Kankakee, IL, to Indianapolis suburbs should prepare for rapid storm motion and potent gusts.

Stay weather-aware: Monitor radar, secure outdoor items, and have a severe weather plan ready. Check local NWS updates and apps for real-time alerts.