2018-7-20 Event: IL, IN, KY, TN

[Clarence Bennett]

Surprised to not see something posted already about tomorrow. Models have been consistent all week driving an anomalously strong trough and upper low into the upper midwest overnight tonight and into tomorrow with jet streak rounding the base and into the MS/OH river confluence by mid afternoon with 3000-4500 MLCape across the region along with deep layer shear. Models have continued push an early morning mcs through w/central KY toward E TN which would lay down a very nice boundary from the NW to the SE roughly along the I24 corridor. If that were to happen, there could be a great play along that boundary back in western KY early on in this event before it grows upscale fast into one large mcs or multiple bowing segments. It is definitely going to be a big hail and wind day, and I wouldn't be surprised to see a tornado or two along a leftover boundary. It is a quick drive from Nashville, so I will likely head for western KY mid-morning. No plains trip this year and rare events like this around here in July have me gnashing at the teeth.

 

[Jeff House]

I agree Friday is likely a local chase day for Kentucky and Tennessee. Hoosier Alley farther north should have a triple point, but I will also focus on the forecast outflow boundary farther south in the Kentucky and Tenn.

Kentucky should have slightly more robust LLJ wind but the upper level flow should be stronger over Tennessee. Regardless I think the forecast outflow boundary is the target. Clarence covers most of the meteorology above.

For those outside our region the area around Mayfield KY is somewhat chasable. A larger fertile crescent goes from Hopkinsville KY to Bowling Green KY like a hammock on a map. Be mindful of the Land Between the Lakes in between, few bridges.

Another area farther southeast in Tennessee is near McMinnville, but not much else in Middle Tenn. Western Kentucky makes the most sense Friday. I'm doubtful from Chattanooga, but I'd go from Nashville.

 

[Dan Robinson]

This remarkable video has emerged of the tornado south of Corydon, Indiana (just west of Louisville, KY). Some of the closest and clearest video of a small tornado vortex that I am aware of:

https://www.facebook.com/patkoch/posts/10156463589263563

This occured at the intersection of an east-west outflow boundary from overnight convection and the north-south warm frontal zone. It was very early in the day as well, around 1PM.