Marginal introduced
...MO...IA...IL...
Early day rain and storms should quickly shift east across MO and AR
along the low-level jet axis. Although the surface low will be
slowly filling, daytime heating will produce a plume of steep
low-level lapse rates across much of central MO and extending into
southwest IA. With 50s F dewpoints and cold air aloft, the result
will be an uncapped and sufficiently unstable air mass to support
low-topped cells, including a few supercells. A broken arc of storms
is expected to form after 18Z over western MO, moving northeastward
toward southern IA and western IL by 00Z. Veering winds with height
as well as favorable low-level buoyancy may support a brief tornado,
along with marginal hail.