April 10th, 2017 Central Illinois Supercell

Tornadoes: 0

Highest Winds: ~30 mph

Largest Hail: 1.25"

On the way home from the day prior's chase, we began to realize that there may be a sleeper play in Illinois the next day (if only we'd just stayed home and waited). In the morning, we awoke to convection from the day before crossing through Illinois, although with promise that the airmass would rapidly destabilize in its wake. Surface winds were expected to be mostly veered ahead of an approaching cold front, but still with lots of speed shear and maybe some turning in the low levels in spots. SPC went slight risk and 2%, like the day prior:

Observed 00z sounding from ILX showing the nature of the wind profiles this day:

I chased solo, but still planned to meet up/potentially caravan with Matt Magiera, Scott Matthews, Paul Sieczka, and Alex Hoffman. A supercell was developing west of the Illinois River as I started southward towards Washington, IL from my house. Just north of Washington, I realized a need to head east ahead of the storm to let it organize more. I headed east to Eureka, then found a good spot outside of town with the storm still gaining steam well southwest. The rest of them showed up over the next several minutes:

The base of the storm was just barely starting to come into view on the horizon when we noticed a distinct, persistent appendage hanging from the wall cloud. This was soon after confirmed as a funnel over Washington. Of course it was behind a cell tower in my only photo of it.

We repositioned a few times, the storm cycling repeatedly. It had good structure, but never got the job done as a tornado producer, unsurprisingly given the straight line hodographs. It maintained its supercell characteristics for at least a couple hours, though.

Beautiful whale's mouth from the RFD surge that finally rendered the storm completely outflow dominant:

Ran into some hail as I core punched just to get home:

Video as I sliced basically the entire updraft region while starting the drive home. There was no danger given the state of the storm at this time. It was really neat to drive through the RFD, then have the precip shut off instantly once I got to the updraft region and under the wall cloud. Rain and hail started right back up once I was north of the wall cloud and into the forward flanking core.

Neat local day. Definitely worth it for the supercell and its structure. Wasn't expecting a supercell with this sort of intensity or longevity, and the lack of tornado potential made it a fun, low stakes intercept.

SPC Storm Reports: