April 6, 2010


Initial Target: Osceola, IA
Departure: Falls City, NE 8:00 am
Arrival: Westchester, IL 11:30 pm
Intercepts: Malcom, IA
Tornadoes: 0
Hail: Non-Severe (pea sized)
Wind: Non-Severe (not measured)
Features: Wall Cloud
Miles: 667


Dryline/Warm front play in Iowa. Targeted initiation on the dryline near Osceola, IA. Departed Falls City, NE where I had spent the night and met up with several chasers in Osceola, IA. Repositioned east and north by warm front in Toledo, IA. Intercepted cells initiating in southern IA near Malcom Iowa nothing rain obscured wall cloud. Followed behind storm noting outflow dominant structure. Lost storm north of Cedar Rapids due to excessive storm speed and lack of road options.

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.





This was the second in a two day chase trip through Missouri and Iowa. Initially, I considered Tuesday to be the lesser of the two days, looking more like a linear event with veered low level winds and more forcing. After Monday failed to fire any storms during the day, Tuesday was looking a lot better. With the forecasted development of a low over central Iowa along with the warm front extending east from there, this area looked like it would have the best directional shear. I targeted Osceola, IA hoping to catch tail-end-charlie on a line that was forecasted to go up.
After Monday's chase I had spent the night on a gravel road just west of Falls City, NE. The road was deserted all night, and it was quite peaceful there apart from the howling winds. The morning sun behind the Mudpuppy.
Morning over Nebraska:
Where I spent the night:
I drove the same course I took the night before, across the Missouri River at Rulo and north on 35 back into Iowa. I stopped in Osceola to get some Subway and check data. I met Derek Weston, Jared Farrer, and crew there and was soon joined by many other chasers including Chris Rice, Mike Brady, Scott Bennett, LB LaForce, Adam Lucio, Ben Holcomb, and Randy Cooper.
Adam, Randy, and Ben.
The dryline was pushing east and the warm front moving north. SPC shifted the tornado probabilities to the northeast and issued a tornado watch. I decided to readjust closer to the warm front further downstream due to the forecasted storm motions of northeast at 40-50 mph. I ran north up 35 and east on 80 with Mike Brady behind me. We went north to Toledo, IA meeting up with Brandon Sullivan. Initiation occurred south of 80 though so we ran down to Malcom, Iowa. Storms were moving fast and needed time to organize so Brady and I sat south of town with Nathan Truninger watching bubbling convection:
Two cells at the top of the line started to look really promising. I made a move on the southern cell. It quickly started to weaken, however, and was moving north to merge with the other storm. I followed the storm north through Malcom, IA noting a high, unimpressive base. Looking north with the storm's base at the top of the image and precipitation core behind it:
Near Malcom, I got a look at the base of the much stronger, northern cell. It was much lower than the weakening cell I was currently under. Looking northeast at the base of a dominant, severe warned cell producing golf ball hail and 70 mph that did quite a bit of damage. The weaker cell merging into this one is visible still at the top, right side of the image:
The storm went tornado warned. I was hoping the merger would result in an even stronger supercell, but sometimes a merger kills of both storms. North of Malcom a shape started to emerge from the rain of the merging cells. My first wall cloud of 2010, looking north:
The chase now became a desperate zig zagging race across county highways to keep up with the storm. We got a little better contrast as we approached the wall cloud. The clouds jutting out of the side of the wall cloud would usually be considered a tail cloud, formed by inflow. They should be pointing to the right given our position, however. It was more likely that a rear flanking downdraft was forcing up scud in a mini gust front.
As Mike and I drove up behind the wall cloud, we lost our contrast and any photogenic view of the storm. We wound up behind veteran chaser Roger Hill as we raced to keep up with the storm. Following it all the way to I-380 north of Cedar Rapids, it became more and more apparent that the storm was going outflow dominant. The merger had not intensified the supercell as I had hoped. A few funnel reports started to come in and the storm regained a tornado warning, but I was pretty sure it was just scud given the outflow dominant look of the storm. We made a mad dash stop for gas along 380 hoping we'd still have a shot at the storm. The locals there, seeing the van, were awash with questions asking where the tornado was and if they would be ok traveling to their destinations. I quickly answered them before we scrambled back onto the road. It was soon quite obvious that we were too far behind the storm to catch up. I called it a chase and Mike and I went our separate ways.
On the way home I hit a few potholes while trying to cut over to a highway to Clinton, IA where I could cross the Mississippi. After that there was quite the vibration at higher speeds and I thought I had done some damage to the van. After bringing it to the mechanics it turned out to be just a massive amount of mud caked into the wheel wells, steering linkages, and the drive train. They chiseled the mud out and replaced the steering linkages and I was good to go again. Yet another reason why I call the van the "Mudpuppy."

Not a bad chase. I got my first wall cloud of the year on the only tornado warned storm in the area, with no tornadoes reported anywhere. I had concerns about storm mode being too linear going into the chase and it seems like that was the case. The chase was not a bust given the wall cloud intercept and lack of tornado reports elsewhere, however.



Lessons Learned: 

  • Clean the mud out from your undercarriage after a chase