May 20, 2004


Initial Target: West of Dekalb, IL
Departure: Bolingbrook, IL 5:30 pm CDT
Arrival: Bolingbrook, IL 9:30 pm CDT
Intercepts: Dekalb, IL 8:00 pm CDT
Tornadoes: 0
Hail: None
Wind: Non-Severe (not measured)
Features: Frequent CG lightning, Flash Flooding
Miles: 188.5


Severe weather potential based on extreme instability with CAPE to 5000 J/kg in northern Illinois.  Waited until two hours after severe watch went up with convection in Wisconsin and Illinois before departing toward Dekalb on 88.  Warnings went up in Winnebago county, headed north on 39.  Got turned around on back roads without intercepting, warnings cancelled.  Ran south on 39 toward Dekalb and greater instability.  Intercepted strong cell on back edge of training line with frequent lightning, flash flooding, but no severe thunderstorm criteria.  Called it a bust after nightfall and headed home.

Crew and Equipment:

Chase team included:  Skip and Bob Talbot.  Equipment consisted of a NOAA weather radio, cell phone, Vortex Anemometer, and TH-F6A Tribander.  Photography by Bob Talbot


I was watching the weather closely because of the instability the models were plotting.  5000 J/kg is extreme, and with a spark the atmosphere will go off like a bomb.  The problem was the cap.  Would it break before sun down and make for a good chase?  The forecasters said it would.  I prepped the car and waited for a sign of initiation.


Earlier in the day there were flood watches out for most of northeast Illinois.  I casually ignored them.  After all, I'm not after flooded fields or high riverbanks but powerful thunderstorms.  My ignorance would come back to bite me later.


My cousin, Bob, said he would chase with me, provided I didn't leave before he got out of school.  While we waited for a sign from the atmosphere or SPC, we went out to get some ice cream with Kristen Miller.  Sure enough, a severe thunderstorm watch went up as soon as we got out of the house.  I figured it would be at least another hour before the cap would break so we continued with our plan (mmm coffee flavored ice cream).  (The watch graphic here shows radar at about the time our chase ended.)

Terrified of thunderstorms, Kristen was dropped off at home.  We gather more gear and headed out at about 5:30, targeting somewhere west of Dekalb.  The plan was to greet the convection that was starting to fire in Iowa somewhere in central Illinois.  We pulled off for gas near Dekalb on 88 and got our bearings.  Warnings started coming in on the weather radio for storms in Winnebago County.  I figured that's where the front was and that's probably where the action would be so we headed north on 39.


Entering Winnebago County we got a look at the towers triggering the warnings.  The sun was brilliantly backlighting this small flanking line.

We turned off 39 onto 20 west, hoping to intercept this storm while avoiding gridlock Rockford.  Here's the top of our tower.

This was an interesting sight.  It looked as if an airplane had punched a hole in the clouds.  It was really just a gap between two towers, however.  We got turned around trying to get off 20, the storm escaping to the east.  The warnings was cancelled not much later.  I made the call to run south on 39 back toward Dekalb and the greater instability.

In Ogle county it became clear we had our storm.  A dark cloud base came into view with frequent cloud to ground lightning.  We started picking up warnings this cell was triggering in Dekalb county.

Light from the setting sun was filtering through the clouds and casting a very eerie orange glow.  Flash flood warnings were triggering the alarm on the radio and frankly I was getting tired of hearing them.  I turned the radio off when they would pop up.

Well, that was my big mistake.  We exited 39 onto highway 38.  Little did we know, but we were heading into the back end of a training line of severe thunderstorms with torrential rains.  Water, pooling in the farm fields, was spilling onto the highway.  I didn't run this photograph through a sepia tone filter, the hue to the sky was just bizarre.  Note the flooding to the right.

The rain came down in buckets, the likes of which I haven't seen in a long time.  I followed the line of cars in front of me not being able to see the road ahead too well.  With a woosh and a muddy wave going over hood we found ourselves in a flooded section of highway.  Water, mud, and crap from the fields was visibly streaming across the road.  I was thinking that was it, the shibster was going to get washed away.  Only about 6 inches deep though, we somehow made it through.  I had to use the oncoming traffic up ahead to tell where the road was because it was hidden under the flowing stream of mud.



We continued on into the line.  We never encountered any of the severe weather the radio warned of, no hail at all in fact.  The lightning was pretty intense, however.  Plenty of CG with the lighting resonating through the rain to cast eerie glows.  With darkness approaching and the rain not letting up, I had Bob plot a course back to the interstate, and we called it a chase.



This chase is being labeled as a partial bust.  We intercepted a severe warned storm, but failed to actually intercept any severe weather or noteworthy storm structure.  Some marginally severe hail reports did come in near Dekalb and then later in the northern suburbs after nightfall.  The extreme instability did not lead to the severe weather outbreak I hoped it would, just a flood outbreak that jeopardized our chase.

Lessons learned:
  • Pay attention to flash flood warnings!  Take a detour to better roads.