April 3, 2011


Initial Target: Iowa City, IA
Departure: Westchester, IL 9:30 am CDT
Arrival: Westchester, IL 12:00 am CDT
Intercepts: Iowa City, IA
Tornadoes: 0
Hail: Non-Severe (0.5 inch estimated)
Wind: Non-Severe (not measured)
Features: Wall cloud
Miles: 500


Cold front setup across eastern Iowa. Chased nose of low where surface winds were forecast to back, but elongated low kept them veered. Chased two severe warned storms noting prominent wall cloud and tail cloud on one but storm failed to produce.

Crew and Equipment:

Chase partners: Jenny Acosta.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Millenicom 760 USB datacard and cradlepoint router, Holux 236 GPS, Robotic camera dome with Sony XR-520V. Canon 60D and EF-S 10-22mm



Sunday, April 3, was an early season cold front setup. Instability was forecast to be quite modest, but with adequate speed shear, lift along the front, and backed surface winds near a low in eastern Iowa, supercells looked more than possible. I was surprised to see SPC go so high on the tornado probabilities, but I wasn't complaining either.
Jenny hadn't chased with me since March of 2008 and she agreed to go with me on this one seeing that it was a Sunday and we didn't have much else going on. This Sunday also happened to be our annual get together with friends at Starved Rock State Park near LaSalle, IL.
We hit up the brunch at the lodge and then spent the morning hiking through the canyons.
By early afternoon we said our goodbyes and shifted into chase mode, taking 80 into eastern Iowa. We met up with Michigan chaser Nick Nolte, sporting his mobile mesonet, at a truck stop and awaited initiation.

Storms went up to our east and rapidly gained severe warnings. We waited for their approach but they congealed before we had much of a view. The surface low wound being elongated across eastern Iowa. Our surface winds veered terribly and I wasn't expecting much structure or tornado activity out of these storms as a result.

Jenny and I dropped south and wound up just east of Iowa City. A big horseshoe shaped updraft base, prominent wall cloud and tail cloud came into view. I was surprised to see such textbook structure and we raced after the wall cloud for a few minutes before it fell apart.

Jenny driving, we turned south again for new, more discrete activity to the south. Storms lined out in a big squall and darkness settled in so we decided to call it a chase and head for home. We got nailed by one of the cores in the process, but Jenny drove through the winds and penny sized hail like a champ.

No tornado, but a fun and leisurely early season chase. We were able to do the whole thing in one day without busting our butts to get out there and got back at a fairly reasonable hour. It was also nice having Jenny with on the chase for the first time in three years as well as seeing Nick Nolte out on the road again.


Lessons Learned: 

  • Elongated lows will veer the surface winds and can kill the chances for tornadoes or sustained supercell structure.