May 21, 2004


Initial Target: North of Davenport, IA
Departure: Bolingbrook, IL 2:30 pm CDT
Arrival: Bolingbrook, IL 10:30 pm CDT
Intercepts: Maquoketa, IA 6:30 pm CDT
Tornadoes: 0
Hail: Non-Severe (0.25 - 0.5 inch)
Wind: Non-Severe (34.7 measured)
Features: Shelf Cloud with lowering
Miles: 417


SPC forecasted potential for tornadoes in Iowa.  Early afternoon Mesoscale Discussion went up confirming a tornado watch, so departed west on 88.  Learned of tornado warned cells north of location in Davenport via weather radio.  Intercepted tornado warned cell in Maquoketa, noting linear appearance, shelf cloud, and green precipitation core.  Over took by core, half inch hail.  Storm weakened but continued to receive severe thunderstorm warnings, headed home on 80.

Crew and Equipment:

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


SPC starts talking tornadoes so I start heading out the door.  I took 88 because I thought 80 would be a little too far south.  What was I thinking?  They both merge to the same spot in Davenport anyway.  It took me an HOUR to clear the suburbs and get on 88, I'm never going that way again.  Plus there are two dollars worth of tolls on that road.


While I am pounding my fists on the steering wheel in Naperville, SPC issues the tornado watch.  The stuff in central Iowa is what I wound up intercepting.  Note the much better stuff in Nebraska.  I gassed the shibster up in the quad cities somewhere.  Davenport's weather radio wasn't talking about the warnings north of me.  Thanks Davenport.  I picked up the tornado warnings on my ham rig from a wx radio station north there.

The storm comes into view.  A dark base, steely blue mammatus overhead, tornado warning blaring on the radio, the adrenaline builds.  Heading north on 61 in Clinton County.

As I approached Maquoketa the base came into view with a lowering to my northeast.  I was hoping this was a wall cloud but it could just be an extension off the shelf.

A ragged base to my north.  Green precipitation core behind it.  This was quickly turning into a hail chase.

This is either a shelf cloud or the dying remnants of a wall cloud.  Sorry for the blurry shots, its hard to drive and shoot sharp pictures at the same time.  I probably should have gotten off the expressway to avoid the core and shoot some better stills, but I charged onward!

I'm in Maquoketa now, madly trying to get east through the city, the storm fast behind me.  The mammatus looms far overheard, ominously warning of the storm's approach.

I made it out of the city, the precipitation starting to overtake me.  Visibility was quite low, but I still looked for a place to pull over and get my bearings.  Here is the radar at about this time.  Rather linear in appearance.

On a small gravel road the gust front overtook me.  I tried to deploy the anemometer but I was a little slow, measuring only 34.7.  The cargo pod on the roof of the shibster probably got in the way too.  I doubt the winds were over 45 mph though.  Then I started getting pinged by some hail.  Here's a short video of non-severe hail in Jackson County.

Windows Media Movie, click to play (450 KB WMV)


The storms were going linear with no new tornado warnings going up, and it was starting to get dark so I called it a chase.  I took random east and south highways in Illinois, snaking my way down to 80.  For awhile I was getting turned around on county roads but I finally made it back. 



The chase was a bust in terms of severe weather and tornadoes.  I also did not encounter much recognizable or noteworthy storm structure.  It could have been worst, however.  I did get my first real hail of the year though.


Lessons learned:
  • Rain-X wears off after two chases.  You have to reapply it!