April 20, 2004


Initial Target: Ashkum, IL
Departure: Urbana, IL 6:00 pm CDT
Arrival: Urbana, IL 8:30 pm CDT
Intercepts: North of Chebanse, IL 7:15 pm CDT
Tornadoes: 1 (my first!)
Hail: None
Wind: Non-Severe: not measured
Features: Striated storm base, wall cloud, tornado
Miles: 31 (scud spot), 140 (tornado intercept)


Intercepted my first tornado!  "Spotted" during an unexpected tornado warning just before 3 pm.  Confirmed tornado not sighted but saw some scud funnel cloud look-a-likes.  Even more unexpected tornado watch went up and raced north on 57 at 6 pm as supercells went up west of Champaign.  Got off near Gilman heading north, finally spotting striated mesocyclone and wall cloud north of Ashkum.  Intercepted brief tornado minutes later before it crossed 57 a few miles north of Chebanse or several miles southwest of Kankakee.  Tornado rain wrapped, spotted power flashes, headed for home as it got dark.

Crew and Equipment:


One car chase team included: Jenny Acosta.  Equipment consisted of a NOAA weather radio, cell phone, Vortex Anemometer, TH-F6 HT Tribander radio.  Photography by Skip Talbot.


What a wild and weird day!  I was contemplating chasing the day before based off some weather models and SPC's forecast which called for a slight risk.  Dewpoints were forecasted to be in the 60's.  A warm front was pushing north and would be the lifting mechanism for convection.  Also present was good wind sheer and southeasterly flow thanks to a near by low pressure center.  Some good ingredients for storms.  The forecasted cape was lacking, however, and the main storm activity was expected to be with a cold front pushing through after midnight.

I awoke to steady rain and a slight risk that excluded most of Illinois.  The only chance looked to be some hailers near the Iowa border.  I disregarded any notion I had about chasing and ignored the weather for much of the day.  SPC's day 1 tornado forecast held no chance for Illinois.

I went grocery shopping, using the radar to coordinate my trip so I'd miss the rain bands.  I was talking to Stan Olson at about 2:15, when to my bewildered astonishment a tornado warning went up for Champaign county!  Where did that come?  Stan scoffed and I scratched my head confused.  Radar showed a mediocre band of showers.

The weather radio aired the warning and described how conditions were right for funnels in relatively weak showers and thunderstorms.  They also went on to describe the differences between funnels and pointy scud clouds (cumulus fractus) that can look like funnels.  Scud!  I knew it: the public was calling in false reports and Lincoln was forced to issue a false tornado warning.


However, I decided it might be neat to catch one of these funnels or at least a good funnel-look-alike to demonstrate the difference.  Jenny wanted to come (even though I warned her we'd be chasing rain showers)  so we both departed west on 74 headed towards the Vermilion county line to head off the convection that trigged the tornado warning.

Low hanging scud?  Boy, was I wrong!  The weather radio blared, right in my face, a confirmed tornado touch down made by trained Skywarn spotters   The tornado produced minor damage and traveled over a mile before dissipating.  The circulation was long gone before we got into position after 3 pm and the warning was canceled.  We exited on 49 to watch the scud go by.

This is what happens when you drag your girlfriend around, for the third time, to chase cold rain showers.

Luckily the dandelions provided a little entertainment while I scanned obscured mediocre convection.

On the way back we spotted more convection going up.  I exited 74 at St. Joseph to get some more pictures.  This is a funnel-look-alike consisting of scud.  The shape gives it away, but its also not rotating, and only has some up and down motion.

Here's another one I spotted a few minutes later.  A better cone shape, still no rotation, however.

A rope funnel?  Probably not.  As this feature dissipated it was clear that there was no rotation.  Still, it looked pretty neat.


We got back on 74 and headed for home.  I wasn't going to call that a chase, but just do a short write up on it as a "spotting event" similar to May 14 of last year.  I came back to the apartment only to learn from Stan (always on top of the situation) that SPC had issued a tornado watch for central IL and IN.  Stunned again, I checked doppler radar to see supercells firing in west central IL, with multiple tornado warnings.

No one saw this coming.  A forecast from the national weather service office in Chicago made at 4 pm started with, "No severe weather is anticipated."  I'd hate to be that guy tonight as over 50 tornado reports came in.  Who knew though?  That's a tough job to have.  At the last moment I decided to chase.  Jenny had an exam at 7 so unfortunately she couldn't come.  Time was of the essence, so I ran out the door having only read the watch discussion text and analyzing the radar loop.  The battle plan was to run north on 57 catching one of the storms as it crossed the interstate.  I was on the road just as a cell far off to my west went severe at about 6:15.  Ashkum was scheduled to be in the path at 7:05 so I called Nick Lockwood and had him punch up a route for me via Mapquest.  I could make it.  The warning was over at 7:15 so I was a little worried that the storm would weaken by the time I got there.  However, at about 6:30 a tornado warning replaced the severe thunderstorm warning.  The storm was building and showing signs of strong rotation.  Gilman was mentioned in the tornado warning so I got off at exit #283.  Shrouded in haze and grunge I could still tell that the storm was still well off to my north.  I took highway 45 north to try and intercept.  I passed Ashkum at 7:05 with the storm still to the north.  Following the road straight, it turned into Main St. and then Oak St. as I passed Clifton.  The storm finally started to come into view and here is where my log finally starts getting interesting.
On Oak St. between Clifton and Chebanse I noticed a white streak to the west.  The streak was diffuse and poorly contrasted but appeared to have some movement to it.  My chest ached at the thought this could be a tornado but I wouldn't be able to tell.  I snapped a few pictures while driving, but it dissipated by the time I pulled over.  The feature is more obvious in the heavily contrast-enhanced version.  It almost looks like a swirling barber pole.  This is a loch ness monster/UFO tornado though and I'm not going to count it.  It could be a landspout, a microburst, or a hail shaft.  Who knows?
As I shot the mystery streak, I got my eyes back on the road to find a large pheasant right in front of my car!  I swerved and missed him narrowly.  Damn bird was watching the storm too. 

North of Chebanse the storm came into view, and what a glorious storm it was.  Well defined updraft region, striations, rotating fingers of scud.  Cloud to cloud lightning arched across the sky.  Looking west, storm movement was to the northeast between 20-30 mph.

(click to enlarge)


Interesting movement on the leading edge of the storm.

Ragged lowerings under the updraft base.

Rotating fingers of ragged scud and an inflow tail forming below.  The features had a real eerie and ominous appearance about them like some sort of giant serpent.

Shibster and the storm.

Well here it is, folks.  The moment you've been waiting for.  The storm was moving off to the north and I got back on the road to keep up, coming closer and closer to the updraft base.  Without warning, a black cone started to dangle below the base.  My heart skipped a beat as I thought, "Oh my god, that can't be what I think it is."  I stopped right then (pulling all the way off the highway) and started shooting.  The cone quickly dropped to the ground before I could fire off the first frame.  It hit the ground throwing a wild spiral of dirt into the air.  I just could not believe it.  I started the day spotting scud to winding up intercepting my first tornado.  That moment was one of the most awe inspiring and exhilarating moments of my life.

(click to enlarge)

After I took that still I switched over to my digital camera's video mode. The funnel seemed to skip, coming and going. I was running real low on memory so I stopped recording when the funnel retreated and started when it picked up again.

WMV movie, click to play (4.7 MB 320x240 Windows Media)


The funnel dips down a second time.  Stan Olson captured the scene from a much closer viewpoint.  His video shows a clear circulation on the ground even though the funnel is not on the ground.  Check out his chase log with video here.  I've been asked several times if I was scared when I saw the touchdown.  My hard work studying storm structure and behavior paid off here.  I knew I was in a safe location, viewing the tornado from the southeast as it moved northeast a few miles away from me.  So no, I was not scared just overwhelmed by this most awesome spectacle.  My tense hands automatically worked the camera and I was able to keep my excitement from screwing up the video


The funnel touches down a third time.  Unfortunately I ran out of memory on my digital camera not long into this video.  I didn't miss much though, a few seconds later the tornado moved into the precipitation core (you can see to the right) and became completely hidden.  Tornado and emergency vehicle sirens wailed, lights flashing.  I couldn't see the tornado at this point but I knew where it was.  Very bright, brief flashes lit up the sky momentarily as the tornado rolled over power lines and transformers.


When the power flashes subsided I pulled into a driveway to clear the highway and make some phone calls.  The weather service was on top of the situation.  The weather radio aired the warning and reported the touch down within a couple minutes of it happening.  Credit goes out to the local law enforcement that made the report.  A local saw me watching the sky and pulled over to talk.  He had been up the road closer to the storm when the winds brought down power lines causing dangerous arching.  With the tornado well rain wrapped, close to a populated area, and nightfall rapidly approaching, I called it a chase.  There is nothing that brings more sheer, white knuckle terror then having to drive through a tornadic storm in complete darkness.  So I retreated to the south, got back on 57, and headed home.  I rolled into Urbana at about 8:30, still dazzled at what I had seen.




After just over 1900 chase miles, 37 hours, and my sixth chase, I managed to catch my first tornado.  Hard work, studying, and determination paid off but I consider myself VERY lucky.  Some have driven tens of thousands of miles before seeing their first, and it will probably be quite some time before I see another.  Unfortunately some of the tornadoes did not keep their fearsome power confined to rural fields.  Utica Illinois got hit hard by a wedge tornado with causalities reported.  The event was just so unexpected, but thankfully the weather service was able to issue timely warnings.  Meteorologists, all caught off guard at the start of this period, will study the event in depth, looking for clues that may have hinted the tornado outbreak.  The synopsis basically concludes that a warm front was pushing north firing scattered thunderstorms, with high helicity values causing low topped supercells to "spin like a top."  However, a more in depth analysis will be needed to accurately forecast such an event in the future.

155 PM CDT WED APR 21 2004

APRIL 20...



Lessons learned:
  • Bring more memory for the digital camera and a tripod for the camcorder!
  • Watch the weather closely, even if there isn't a forecasted risk.