June 22nd, 2015 Sublette, IL EF2 Tornado

Tornadoes: 1

Largest Hail: N/A

Highest Wind Gust: 50 mph (estimated)

This was my benchmark chase of the year, and given 2014 was really inactive, the last 2 years. It was an extraordinarily hyped up event, and had attracted the attention of chasers around the country. It looked like primarily a Wisconsin/Michigan event until really the day of, when the mesoscale details worked themselves out. As with other events of 2015, this one found its way to northern Illinois. Perfectly fine by me.

The day was highly conditional. A cold front was draped out to the west with an outflow boundary intersecting it in Iowa, but extending into northern Illinois. The boundary was left by a pretty exteme squall line that ravaged portions of Iowa with 90 mph winds. The cloud cover was what I was sure would kill any potential.

SPC made some major changes to their outlooks through the day, but maintained 10% tornado probabilities. By 1630z, they had the right idea:

By about 2 PM, SPC issued a fairly modestly worded MD, for which I do not blame them:

Some breaks in the clouds occured over portions of eastern Iowa and northwest Illinois by

about 4 PM, but I was fairly certain we would not be able to recover from the cold pool left by morning storms. But by 4 PM, a Tornado Watch had been issued:

By 5 PM, 2000-3000+ j/kg of MLCAPE had built up across the area, probably owing at least in part that it was early summer. Craziness would soon ensue...

I was volunteering for kids at our local conservation area in the morning and early afternoon, basically going nuts that I couldn't closely monitor the weather. I did, however, sneak peeks at my phone to watch radar and to track the boundary, which I knew would come into play. I got out of there by 2 PM, basically sure that the day would be a dud. I also had a doctor's appointment at 4 PM, but when I noticed peaks of sunshine, I grew a bit worried I'd miss something. When we got back from that, and when I saw that storms were developing in eastern Iowa in a much more recovered atmosphere, the game was on. We made our way north, toward I-88 as two supercells were developing. One crossing the Mississippi just south of the Quad Cities, one crossing north. Because the northern one was more well-defined at the time, we went for that one. We got our first good visual of it west of Sterling.

A rather grungy wall cloud at the intersection of inflow band/RFD:

Incredible RFD surging forward as it's about to wrap about the wall cloud and drop a rain wrapped tornado:

Inflow band feeding into the storm. It had the most rapid motion I've ever seen into a storm (which I guess isn't saying much given my inexperience):

Video of the structure:

Time lapse/sped up video of the updraft area. You can see the convergence very well:

From here we bailed east the south through Sterling as RFD caught up with us. We had gusts capable of some minor damage, but nothing too extreme. We continued southeast until we could finally race ahead of the updraft. Radar showed the storm's inflow opening up, making the updraft area visible for some window of time. As we headed east, there was what I'm almost completely sure is a wall cloud with areas of dust getting kicked up nearby if not underneath it. It could've been outflow, but the tornado developed at nearly the same time. But then again, it was so low contrast that I can't draw any conclusions. We kept east, getting enough ahead of the RFD that we could see way back into inflow notch. Slowly but surely, a thin figure extending to the ground emerged. We have a tornado!

Although at the time I had doubts about it actually being a tornado, it was. We pulled over to film it, almost directly to its south by a mile or so. Any doubts of it being a tornado were suppressed when plumes of dust and some debris got rapidly inhaled into the base of it. I'm pretty sure based on our positioning that it was entering Woodhaven Lakes right then. Another 30 seconds later, the RFD wrapped right around, blocking our view.

Low quality video of the tornado:

We raced east to outrun the tornado to our next south road option. The tornado had a bit of a debris signature and had quite the velocity signature. With it a mile or less behind us, we scurried south.

I knew Mendota was coming up, and I knew it's a fairly populated town, so unlike the rest of the chaser crowd, I decided to take back roads around the town instead of heading straight through it and potentially getting stuck in traffic with a tornado bearing down. It put us a bit out of position, but overall I think it was a smart move. Another EF1 tornado went right through the center of Mendota. We realized we would never catch up, and it was getting dark, so we called off the chase at Troy Grove.

The storm would go on to produce more tornadoes. This includes the EF3 Coal City tornado, which left lots of destruction in its wake. The first supercell was a monster that developed in eastern Iowa near Clinton and moved clear across the state of Illinois, leaving destruction in its wake. There was a second one as well that developed just behind the first one that dropped a brief EF0. The other supercell I mentioned crossing the Mississippi River south of the Quad Cities also produced a large EF2 near Illinois City. After seeing a tornado on an intense chase in Iowa 2 days beforehand, I witnessed one of many tornadoes during this Illinois outbreak. Hopefully 2016 (or maybe fall 2015?) treats me just as well, if not better.

NWS tornado tracks: