Missouri Heat Boundary Ignites Severe Wind Threat into Illinois — SevereWX

Missouri Heat Boundary Ignites Severe Wind Threat into Illinois

A hot, uncapped boundary layer across central and southern Missouri is setting the stage for severe thunderstorms capable of 55-70 mph damaging wind gusts this late afternoon into evening. SPC's Mesoscale Discussion 2001 highlights the risk extending into southwest Illinois, with a 60% chance of a severe thunderstorm watch.

Visible satellite shows remnant boundaries from earlier storms draped over the region, but south of northeast Missouri's residual cap, temperatures have soared near 100°F. This has sparked boundary-layer cumulus amid 2000-3000 J/kg MLCAPE. While an MCV along the Iowa-Missouri border provides stronger lift to the north, the prime severe zone sits farther south.

CAM guidance varies on exact storm initiation, but agrees on potential upscale growth into a mesoscale convective system (MCS) tracking into southern Illinois tonight. Isolated damaging winds look likely with intense storms, ramping up if cold pools coalesce.

Peak wind gusts could hit 55-70 mph, posing risks to power lines, trees, and travel in affected areas including St. Louis metro vicinity.

Monitor convective trends closely. SPC and local NWS offices (LSX, SGF, EAX, PAH) are watching for watch issuance.

Preparedness: Secure loose outdoor items, avoid flooded roads, and have multiple alert sources ready. Stay weather-aware as storms develop.