February 27, 2024

I tried to intercept a tornado warned storm north of Mendota after dark and wound up getting snagged in the forward flank of a nearby cell and bounced around with no view for a bit before exiting to the east. There I picked up a visual of the storm's rear flank gust front with a thick inflow band feeding in from the east.

A rounded lowering was present on the gust front for some time before I gave it any consideration as I was focused on trying to see something backlit deep within the core where I expected a tornado.

However, the lowering started to "rope out" as if it were a dissipating funnel cloud, and indeed it was.

The funnel became more defined, the rotational speed increasing as it was stretched in the rope-out.

This funnel wasn't in the "right place". It formed out of what appeared to be a nub shaped kink on the lead edge apex of the RFD gust front. I suspect it was a gust front mesovortex, similar to what you'd see on a QLCS, rather than from the supercell's mesocyclone. I wasn't even seriously considering it until the nub started to obviously rope-out. It happens sometimes where the bowing gust fronts of two training cells intersect, the actual mesocyclone was buried much further back in the storm's core. I saw a well defined couplet over the feature for only a scan or two and after it had roped-out. These are usually shallow bottom-up circulations, and they show up on radar probably after they've dissipated and the rotation migrates higher up in the base.

The rest of the rope-out sequence:

I ran east a few miles to try to chase this cell, but I was solidly south of the RFD core with no view into the notch of what was becoming a gnarly HP. I wasn't about to chase an HP into the western suburbs, especially after dark, but many chasers did apparently, nabbing views of a tornado. I called the chase and bailed south for home.