July 13, 2004


Initial Target: La Salle County, IL
Departure: Champaign, IL 12:00 pm CDT
Arrival: Champaign, IL 5:00 pm CDT
Intercepts: El Paso, IL
Tornadoes: 0
Hail: Severe Golf Ball to Hen Egg (2.1 inch measured)
Wind: Non-Severe (not measured, damage encountered)
Features: Significant Severe Hail, Mammatus
Miles: 337.5


Widespread severe weather expected with large CAPE and good wind sheer.  Tornado potential but more favorable for hail and wind.  Left at noon targeting discrete supercell in northern IL.  Intercepted tornado warned line near La Salle county, encountering quarter sized hail.  Two inch hailstone found outside of Streator.  Golf ball sized hail in El Paso.  Several lowerings noted but missed F4 tornado near Eureka.  Followed line back to Champaign noting wind damage and mammatus.

Crew and Equipment:

Solo chase.  Equipment consisted of a NOAA weather radio, cell phone, TH-F6A Tribander.  Photography by Skip Talbot.


I had been following this setup a few days before it came about.  CAPE over 4000 J/Kg and a prominent mid level jet streak were in place for widespread severe weather.  The cap was weak so initiation was expected early and to evolve quickly into severe lines and bow echoes.
The plan was to hit the road as soon as I got back from class.  To my dismay I found that a perfect discrete supercell had fired in northern IL and a tornado watch had already been issued.  I assembled my gear and headed out the door as soon as possible.  The cap had broke even sooner than I though.
I headed north on 47 hoping to catch the southwestward moving supercell as it crossed the highway.  I spotted the storm in Livingston county as it was putting out a tornado warning for La Salle county.  Mammatus arched far overhead and from horizon to horizon.  I could tell this thing had already blown up into a line.
I could not find a workable point from the front of the storm so I decided to punch through it and head west hoping to get the updraft base where it wasn't obscured by dense precipitation.  Near Streator I got into some quarter sized hail.  One bounced into the car when I rolled down the window to shoot some video.  This was the largest hail I had ever seen, but I was in store for even more.  Check out that impact shape.
I followed the line south noting sharp precip cores but nothing was really grabbing my attention with the storm structure.  Its frustrating chasing a line and trying to find a workable point.
About 5 miles west of Streator I saw this hailstone lying in a farmer's driveway.  Using the quarter to measure the hailstone, I later deduced the stone to be 2.1 inches in diameter.  Now that's big hail.
As I neared Woodford county, new warnings were going up and reports started coming in of "spotters reported large tornado on the ground."  Well, once again I was missing the show.  Entering the town of El Paso I came upon a real eerie sight.  The sky was green, El Paso was mentioned in the path on the radio, and the rain had let up to golf ball sized hail.  I got video of it smacking the car, but ruined it by cursing continuously as the stones hit the windshield.  Luckily, the shibster came out without a scratch.
I cleared the town of El Paso and the precipitation as well.  I noted several lowerings but couldn't confirm any of them as wall clouds.  The weather radio was going crazy, "multiple tornadoes in Woodford county."  Well, where were they?  Just outside of El Paso I past a car that was pulled over.  What was he looking at?  I swung around to get a better view.  A brown plume was rising from a field not too far away.  This was it!  A tornado just starting to form.  I jumped out of the car and hit the button to start shooting video.  NO MEMORY SPACE.  More curses.  Just like in the movies, where the guy fumbles to load ammo into his gun as the monster charges, I fumbled to load the other memory card in.  After about four attempts I finally got it.  I shot about 10 seconds and then ran to the car to use the window sill as a tripod.  After another 15 seconds of shooting I started to look around.  I was real close to the storm but not directly under it, the plume was not moving, where was the rotation?  That's when I felt like an idiot:  some farmer was burning junk in his field and it was billowing brown smoke.  I sure fell for that one hook, line, and sinker.
I continued west, even though I should have gone east.  It didn't matter though since the tornado and hail activity had pretty much died out at this point, leaving a Derecho with powerful winds.  I noted this lowering a few miles west of El Paso.
I turned around and started heading back east.  This lowering came into view and was my most promising lead of the day.  It looked like a small, yet very low, block wall cloud with a small inflow tail (RFD behind it?).  I got up right next to it, but it quickly fell apart.  Everything seemed like it was going outflow dominant.
Nearing Bloomington, this emerged from the rain.  I pulled over promptly not knowing what to expect.  It had a nice shape to it but I couldn't discern any motion.  I drove up closer to it but it fell apart.  I can't confirm what it was, but most likely just a "scud bomb."
Contrast enhanced.  It looks like a tube touching the ground, but the way it fell apart and the other junk scud next to it leads me to dispel this as any sort of vortex.
In Bloomington the sirens wailed and everyone was out of their cars watching a various corners of the sky.  I don't know what they were looking at but I didn't see anything worth pulling over for.  There was lots of low scud zipping around, which the public probably thought were funnels.  I followed the tornado warned line all the way back to Champaign.  I saw an overturned semi and snapped this mammatus picture as I entered town.
 Back at the apartment, I got an update on the radar to find a derecho (large bow with continuous severe wind) with embedded supercells.  I gave up on chasing that as it was screaming off to the south, but saw a lone towering going up behind the line.  It had some nice structure and a small pendant shape on the radar so I headed up north on 57 to catch and perhaps get some more mammatus shots.  In Paxton I noted lots of wind damage, but didn't stop for pictures, not wanting to gawk.  There were large trees down, some metal roofs had been peeled back and parts carried 50 yards, and garage doors were blown in.  The damage was widespread and caused by straight line winds, not a tornado.  Well the lone storm just up and vanished and the mammatus raced south with the line so I turned around and called it a chase.

This was another, "just missed the tornado chase."  I more than accomplished my goal of intercepting severe weather, yet its still disappointing and frustrating missing the tornado.  And what a tornado it was, an un-obscured wedge that the NWS rated an F4.  Here's some pictures and the damage survey.  The line went on well into the night causing widespread wind damage from central Illinois all the way to Tennessee knocking out the power in parts of Champaign and Danville.

Lessons Learned:

  • When the cap is weak you must leave early.
  • Derechos make for dramatic severe weather, but difficult for tornado interception.