06/18/2026
Probability of Watch Issuance...80 percent
SUMMARY...The severe risk will continue spreading/developing
eastward tonight. A few tornadoes, damaging winds, and severe hail
are all possible.
DISCUSSION...As a midlevel wave and accompanying strong midlevel jet
streak continue tracking eastward across the Midwest into the Great
Lakes, an attendant surface low will track eastward from WI into
Lower MI during the next several hours. In response, a 60-kt
southerly LLJ (sampled by the IND VWP) will continue translating
northeastward across eastern IN into central OH tonight. The wind
profile across this region is already robust, with a large
clockwise-curved hodograph sampled by the ILN 00Z sounding (300
m2/s2 effective SRH) -- and further increases in size/curvature can
be expected with the strengthening LLJ.
While buoyancy is marginal with eastward and northward extent,
recovering PBL air should continue spreading east-northeastward
tonight, supporting surface-based convection. As a result, the
potential for severe storms (including supercells) capable of
producing a few tornadoes, damaging winds, and severe hail will
continue eastward into the overnight hours. A downstream tornado
watch is likely.
