December 31, 2010


Initial Target: Bloomington, IL
Departure: Westchester, IL 12:00 pm CDT
Arrival: Westchester, IL 3:30 pm CDT
Intercepts: Pontiac, IL
Tornadoes: 0
Hail: Non-Severe (0.25" estimated)
Wind: Non-Severe (not measured)
Features: None
Miles: 199


HIgh shear/low cape cold front setup in IL/MO. Initially targeted MO, but called off chase after analzying morning data and went back to bed. Awoke to tornado warnings across central IL and made an impromptu chase targeting Bloomington. Intercepted tornado warned cell near Pontiac IL noting low contrast, grey, grungy storm and little structure. Let core pass overhead with no view inside or on back side of storm. Pursued storm east a few miles until it weakeened and called off chase.

Crew and Equipment:

Solo chase.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Kyocera data card and router, Holux 236 GPS, Robotic camera dome with Sony XR-520V.




I had been eyeing this setup with skepticism given the marginal parameters with less than 500 Cape across most of the warm sector, and questions about lingering precip. Still, warm air advection with temps into the 60's in central IL and strong shear profiles supported a potential severe weather event. I woke up at 6 am on new year's eve to check the data. Storms had initiated overnight across Missouri in much the same fashion as the October 26 setup and were racing towards St. Louis. I decided that points further north were probably out of play, socked in by rain and cloud cover and went back to bed.

I woke up at 11 to see a half dozen counties in Illinois tornado warned. The storms looked rather sloppy and embedded on the radar, but I kicked myself for going back to bed. I grabbed my laptop and cameras and ran out the door. The robotic camera dome was down for repairs. Tornado warnings extended from southwest of Bloomington to St. Louis. I figured I would head down 55 and catch one of the more promising cells on the northern end of the line as it crossed the interstate. The fast northeast motion sent the storms in my direction and kept them from crossing the interstate right away. Most of the December snow had melted except for the larger piles, which were producing a bunch of fog. I figured the cooling near the surface from the snow wouldn't help chances for a tornado, and I'd probably have to get much farther south than I could make it in order to have a decent shot at intercepting one.

Warnings started to fizzle as I headed south and I feared I was making a fool's effort at these cells, coming in late to the show. As I approached Pontiac, however, a cell in the line flared up and went tornado warned. Just 15 miles to my south, I was in perfect position to intercept and even encountered a smattering of small hail as I approached from the north. I was on the storm within minutes and pulled off the interstate and stopped at the top of the off ramp to watch the storm come in. There was a grey, low contrast core approaching with a rather short and ragged updraft base on the forward flank. The contrast was super low, and the structure pretty lack luster, so I didn't even bother getting the camera out. I figured, if there was a tornado it was probably embedded, so I let the core pass overhead, but saw nothing from within the storm.

The rain tapered off slowly on the back end of the storm, so there was even less to see after the storm passed. I gassed up in Pontiac, diverted around the town and then headed east a few miles on county roads to to try and get out of ahead of the southern portion of the storm as it was bowing out. The storm fizzled though and lost its warning, so I called off the chase and started heading home.



On the last day of the year, this was my first December chase. It was ultimately a bust, however, after intercepting a tornado warned storm and having no storm structure worthy of a photograph, just grey skies. Unfortunately, there were several tornadoes, mostly in Missouri, but some in Illinois that did cause fatalities and significant damage. This is the worst kind of weather setup, in which you have tornadoes strike populated areas killing people, instead of out in rural areas where only storm chasers observe them from afar. This is what happens on high shear/low cape days though. You get fast moving, low contrast, grey, grungy storms that hit without a visual warning and provide no view for storm chasers. Its a lose lose situation. Ultimately, no storm chaser that I'm aware of got good video of any of the tornadoes. The best video came from locals filming from their porches that were dangerously close to the circulations.


Lessons Learned: 

  • Even if you don't think you are going to chase, don't go back to bed if conditions support tornadoes.