October 18, 2007

Statistics:

Initial Target: Peotone, IL
Departure: University Park, IL 5:00 pm
Arrival: Bolingbrook, IL 11:30 pm
Intercepts: Peotone, IL, Lafayette, IN
Tornadoes: 0
Hail: Non-Severe (not measured)
Wind: Non-Severe (not measured)
Features: RFB
Miles: 374

Summary:

Very powerful extratropical cyclone over MS valley created strongly sheared setup with marginal to moderate instability.  Timing was an issue as storms looked like they could fire early, but initiation held off until work was over.  Left University Park at 5pm with low topped LP storms passing nearby.  Traveled a few miles to watch line of cells going severe warned, and did not pursue as storms moved into Chicago.  After sunset, traveled further south where several tornado warned cells were passing south of Champaign.  Forced to play catch up for two hours due to storm speeds, only witnessed RFB with ragged lowerings for a few minutes before calling off chase due to accelerating storms speeds.

Crew and Equipment:

Solo chase.  Equipment consisted of a TH-F6A Tribander, and GPS/Cell Phone equipped laptop.  Photography by Skip Talbot.

Details:

The biggest setup of the year for Illinois, and I was most likely going to miss it due to work.  I had just started a new job and absolutely could not take off.  A sub 980 surface low was moving up the MS river valley with an impressive 90 knot midlevel jet.  Ongoing activity from overnight convection looked like it would limit instability, however.  Storms were also forecast to fire early, and the timing made storm mode uncertain.  The low level shear was definitely there for tornadoes though.
Unable to watch the weather at work due to a lack of internet, I did see sunny skies and a nice cu field during my lunch break.  Surface winds were also impressive.  A lack of significant forcing was holding off initiation until the jet arrived in the late afternoon.  Things were looking up for a chase after work.  Although I wasn't able to closely watch the weather that afternoon, I believe that a dry punch brought in by a strong south-southwest low level jet was mixing out the surface dewpoints.  Dewpoints continued to drop throughout the afternoon into the evening.  When I got out of work, there were several lines of cells from northeast Illinois down to Kentucky.  A tornado watch was in effect for most of the outlook area and there were numerous warned cells to the south.
I was pleasantly surprised to see a storm going overheard right where I work.  It looked a little high based, and very dry.  Only light bands of rain and virga were falling from it, and it looked like a mini LP (Low Precipitation) supercell.  The dryness made for some excellent contrast, and made the storms very photogenic.  The cell pictured here went on to become the first severe warned cell in the line as it passed over northern Will and Cook counties.  Looking west at the RFB:
Cells continued to organize in the line so I decided to play them instead of tearing down 57 after the warned stuff.  I moved down to Peotone and pulled off in front of a farm on Wilmington Rd.  The lighting and contrast on these cells was amazing, some of the most photogenic stuff I have seen in quite awhile.  This storm was severe warned at the time of the picture.  Looking west at an RFB and interesting little protrusion from the base:
Although the storms weren't doing much in the way of exhibiting thrilling tornadic action, they were simply beautiful.  I stood back enjoying the view, thoroughly pleased.  In one shot I was able to capture bubbling convection atop the low topped storm, highly sheared mid levels, and a high contrast RFB with great blue and orange coloring:

The farmer whose farm I was pulled over in front of came down to check up on me.  He was extremely friendly, and I showed him all of my gear and the current radar.  He said people always come down that way to watch the weather, and with good reason.  Wilmington Rd. has horizons like western Kansas.

Looking south at a weaker, but still very photogenic line of cells:
The farmer said I was welcome to stay and watch before he went back up the driveway.  I think he released his attack cows on me though as these little guys came running out towards me a few moments later, mooing loudly.  I guess they thought I had food or something, as they really wanted to come over to me.
As the storms traveled northeast into the suburbs and Chicago, I let them go, even as they continued to strengthen.  Chasing the suburbs or anywhere near the city is a futile cause, especially during rush hour.  Instead I decided to book it south after some tornado warned cells all the way down by Tuscola.  Along the way I caught one of the most glorious sunsets I have seen in a long time.  There were brilliant golden rays cast around bits of cloud that looked like they were painted onto the sky.
After nabbing a few pictures of the sunset.  I jumped back on 57 and raced south towards the tornado warned cells.  I knew it would be well after dark before I intercepted, but I was ready for a night chase.  I planned to go south until I had an east option and catch the storms from behind as they crossed my path.  I was making good time on the interstate and the weather radio reported a warned cell moving northeast at 35 mph.  I wound up choosing 74 for my east option, and as I passed Champaign Urbana, it became apparent that these storms were moving much faster than 35 mph, and I would be intercepting well into Indiana.  Andrew Pritchard and Mark Sefried had been on the cells for quite awhile, and while I was still 30 miles behind my storm, they had bailed and were heading back home.  I felt like a fool racing to catch storms that would lead me into Indiana and probably fizzle before I got there.  I had come this far though and I couldn't just give up.  As I crossed into Indiana the storm I was after crossed north of 74 well ahead of me, pretty much killing any chance for a clean intercept.  I had to exit and zigzag north and east, which was slower, and didn't allow me to gain any ground on the storms.
 The storm, which had been only severe warned for about a half hour as if it were dieing, suddenly strengthened, took on a more classic supercell appearance on radar and regained its tornado warning.  I was able to get a glimpse of the storm's base several miles southwest of Lafayette.  I noted some ragged lowerings, but didn't see any tubes lit up by the sporadic lightning.  Radar at 01:14Z (9:14 EDT) indicating a tornadic vortex signature (Pink Triangle), and my GPS location (White Circle):
As I approached Lafayette I finally caved and let the storm go as the strengthening jet made it accelerate.  I called the chase off at about 8:30 and made it home by 11:30..
Conclusion:

The biggest setup in Illinois of the year also meant the fastest storms speeds of the year, and I'm labeling this chase as a bust as a result.  The chase wasn't a complete loss, however.  The sunset storms I caught right after work were truly gorgeous.  It was one of the most photogenic skies I have seen this year.  Andrew Pritchard and Mark Sefried wound up getting a nice wall cloud and a couple brief funnels on the storm before the sun went down.  Chad Cowan and a couple of his chase partners targeted central Indiana and wound up getting behind an F3, and losing an entire tire when they drove through some debris.  They had a lot more excitement that night than I did, but wound up spending half the night at a disaster scene.

 

Lessons Learned:

  • Photographing a beautiful sunset sky is more rewarding than racing after nocturnal tornadic storms 100 miles away.
  • Take a moment to assess storm speeds.  The minute you lose on the chase can save you 300 miles of frustration.