July 17th, 2016 Putnam County, IL Tornadoes

Tornadoes: 2

Highest Wind Gust: N/A

Largest Hail: N/A

(All images in this log are watermarked "©2017 Billy Faletti," even though they were taken in 2016. I noticed but I'm too lazy to go back and change it.)

Continuing the relatively active period of storms across the Midwest, July 17th had potential to be a sleeper day across portions of SE Iowa, NE Missouri, and into Central Illinois. While not a major day by any means, a boundary laid down by a morning squall line in northern Illinois could provide enough forcing and low level helicity under some moderate zonal flow for supercells, and maybe a tornado or two. As is typical with summertime in the corn belt, major instability on the order of 4000-5000+ j/kg was present, along with steamy dewpoints into the upper 70s. The game plan was to play the boundary in west-central Illinois where it looked like storms had the highest chance of forming. I planned to meet up with Matt Magiera and Scott Matthews, with an initial target of Macomb.

Due to possible boundary interaction on an otherwise marginal setup, SPC issued a 2% tornado risk:

The aforementioned squall line rolled through around 7 am, impacting my house directly. I was already awake to monitor the setup, so I grabbed my DSLR and headed out to the end of my driveway for some shelf shots. To my surprise, when it started to approach, there was some structure that reminded me of a transient supercell.

Inflow feature/tail feeding into the line:

Bowing outflow/"RFD" to the south:

The line rolled through with nothing more than some briefly gusty winds, definitely sub-severe. However, its precious outflow boundary looked to set up over west-central into central Illinois as planned with plenty of time for airmass recovery. At around noon or 1 pm, Matt and Scott got to my house, and we were off to Macomb. It was a couple hour drive, and we monitored the setup with nothing major really changing. Our biggest concern was that there wouldn't be enough forcing to break through a moderate cap. It was clear, however, that if it did break, high to extreme instability would allow for some robust updrafts.

We finally arrived in Macomb, monitoring the northward progress of the boundary that was now visible on radar. While waiting, we grabbed a bite to eat at McDonald's and parked next to a park. It was amusing watching multiple kids, teens, and young adults walking around, glued to their phones, occasionally stopping abruptly and vigorously swiping upward. Ah, yes. They were all playing Pokemon Go. This was at the height of its popularity, and when I figured out Matt and Scott despised it, I opened the app on my phone at full blast. Getting on people's nerves is fun.

Mid-to-late evening, cumulus began to go up, but would succumb to the capping inversion and come crashing back down again. We were pretty sure it was going to bust. We had chased the boundary, which was now racing northward, to Galesburg. After assuming we'd busted, we got on I-74, took an exit, eventually arriving in Chillicothe where we got gas. It was when we did this that we realized radar returns were beginning to become appreciable, in the 35-40dbz range. And they had the pointed sickle shape of developing supercells. AND they were about 10 miles southwest of my house, where we had been 5 hours earlier. Of course we and the developing storm were hugging the Illinois River, so road options and terrain were very lacking. Still, we made ground as the storm became a full-fledged supercell, albeit a relatively tame looking one.

Arriving in Lacon, we crossed the river. On the bridge we could get a view well above the treeline, where a well-defined wall cloud unveiled itself. It looked to me like part of the wall cloud was reaching for the ground. It was still 10-15 miles to our north, but it kind of looked like a cone funnel right off the surface. Not expecting to see the structure, I tried getting my cameras turned on before we lost the view, but they took too long to start up. We talked debated amongst ourselves as to whether or not it could've been a tornado. Regardless, it got us excited for when we finally caught completely up for a view.

Driving north up IL-89 in somewhat better terrain, we started to once again catch glimpses of the base through the trees. It was at this time a tornado warning was issued. It looked like my aunt, uncle, and cousin, who lived in McNabb, would cut it close if there was a tornado. I used Matt's phone to call them since mine was dead. Right after doing so, we came across a good east/west option and turned west. The base looked rather featureless except for a small protrusion with some rotation in it. It was definitely a funnel, and there was even an inner helix to it. We pulled into the end of someone's driveway, and only about 30 seconds later the owner approached us, not happy we were there. We pointed to the funnel and told him there was a tornado warning. He then snapped back that it was on the ground only a few minutes ago. Crap. We missed the majority of it because we were driving through trees. At least we'd caught the very tail end of it as it passed between Florid and McNabb.

Funnel/dissipating tornado:

Our view was incredibly wimpy, but at least we caught it. Someone caught some impressive video of it outside their house near Florid, and it had a pretty robust funnel with rapid motion. Kinda hurts being only 4 miles from home, but again, at least we caught it.

We drove about 2 miles north to catch the circulation as it crossed the road, and pulled off at what looked like a business near McNabb. I ran through the ditch in front of the building to get a better view in a bean field when a guy opened the door, very unhappy and threatening to have his dog come after me. Welp, it was a house. The circulation was nearly overhead and we were half reveling in the swirls of the now-occluded meso, half apologizing for tresspassing. Looking back, what I did was stupid and I wasn't thinking clearly because of adrenaline from being right under the rotation. After both encounters with land/homeowners, I decided it's probably good to avoid parking in driveways while chasing. I still get anxious thinking about the latter encounter, but live and learn I guess.

It became clear the storm was weakening and wouldn't produce another tornado, and it was getting dark, so we set up tripods to catch some lightning shots of the dying updraft tower. Of course the big CGs quit once we did so, but good structure and in-cloud lightning still allowed for some great shots:

We got to my house, reviewed video a bit (when I dropped my new camcorder, popping part of the screen out because life is great), and parted ways. Later that night, someone posted a video to Facebook of the feature we were looking at on the bridge in Lacon. There was circulation at the ground, so turns out we saw another tornado. Not bad.

A good day, although my wimpiest tornado day. I finally saw a tornado in my home county. A good forecast on our part, although our positioning was pretty off and we wouldn't have seen anything had I not lived where the storms went up. We were right that brief tornadoes were possible, but mesoscale boundary positioning and forecasting is not easy.

SPC Storm Reports:

GPS Location History: