July 23, 2011


Initial Target: Granite Falls, MN
Departure: Aberdeen, SD 10:00 am CDT
Arrival: Westchester, IL 6:00 am CDT July 24
Intercepts: Madelia, MN
Tornadoes: 0
Hail: None
Wind: Non-Severe (not measured)
Features: Wall cloud
Miles: 789


Warm front play across southern MN.  Targeted south central MN for late afternoon supercells.  Low topped, mini supercells waited until near dusk and struggled to go up against the cap.  Played up the line as the cap culled the cells to the south, noting a small wall cloud near Madelia and pretty sunset storm structure.  Caught a pointy lowering near Madelia just after dark but unable to identify what it was.

Crew and Equipment:

Chase partners: Jonathan Williamson.  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



Jon Williamson and I were on our second day of a two day northern plains run.  We awoke in Aberdeen, SD and were rolling by mid morning, heading due east into Minnesota.  The day’s setup looked fairly modest but a decent shot at slow moving supercells with broad zonal flow and strong instability.  The cap looked to be the main problem so convective initiation was in question, but the high resolution models all had storms developing by evening. 

Jon and I headed toward a line of storms that was tracking through central Minnesota.  The storms were sitting just north of the warm front, where the boundary layer was stable.  Thick cloud cover extended north of the front where the elevated storms were, but the sun was shining strongly south of the front.  We tracked behind the line of junk storms expecting new development on the southern end or an outflow boundary to kick up new storms.

As we plodded along, the new van had developed a pronounced shimmy.  The shaking was jarring and unsettling.  I would have been worried that the van was going to break down, but I had felt that shimmy on the old van, the “Mudpuppy,” a couple times in the past and knew what it was.  The undercarriage and axles accumulate a lot of mud when driving on the backroads and the added weight throws the wheels out of balance causing a bad shimmy.  I was disappointed to see that the new van was having the same issue.  We stopped in Benson, MN to find a carwash with an undercarriage wash   If the mud dries and hardens, it sticks to the axles like cement and has to be chiseled off.  I was hoping we could get it off of there before I had to take it into the shop.  The undercarriage wash didn’t seem very potent, and it didn’t help.  We were doing the rest of the chase and the trip home with the shakes.

We watched towers to our northeast continue to move off into central Minnesota.  Behind the cold pool they’d probably never become surface based.  The high resolution models were indicating new development across southern Minnesota by early evening.  We abandoned our northern target and started heading south, taking the same highways Jennifer Brindley and I were on just a couple weeks earlier.

We pulled off on a farm road near Windom, MN and met up with chase Nick Nolte.  A crop duster flew by and dusted the field next to us. 

We waited for hours for initiation  The July humidity was insufferable and the mosquitos were out in the middle of the day as well . The rapid refresh continually indicated that storm initiation was just an hour away.  An hour would go by and no storms and still the models said the same thing.  Finally at around 7pm, as the sun started getting low in the sky, the cumulus field that was overhead start to grow vertically.

Towers struggled to get airborne, but they finally started to get going.  A line of cells emerged from the bunch of towers and we hopped on one of the more prominent looking ones in the middle of the line.

The setting sun lit up the convection in beautiful golden shades.  The storms were little more than glorified turkey towers, however.  It seemed like lack of lift and remnant capping was preventing the storms from taking off.  We watched on the radar as cells to the south were culled by the inversion.  Our storm, while developing a nice base and low topped anvil above a skinny updraft tower, was starting to die as well.  The base shriveled and only an orphaned would soon be left.

Meanwhile, a Spotter Network report of a wall cloud came in on the next cell up the line.  We raced north for the intercept. 

Coming in on the back of the cell, we could see the wall cloud to the east.  The storm was pretty shades of pink and purple in the last light.  The wall cloud was positioned far behind the sharp angle of the updraft tower.

The cell started to sputter too, and we figured the cap was going to cull this one as well.  We continued north for cells that were interacting with the warm front, figuring they’d be the last to get killed by the cap and had the most favorable directional shear and extra lift to work with on the warm front.

Passing Madelia, MN, memories of my second tornado intercept from over six years ago came back, which happened just a few miles from our location.  The last bit of light faded as we entered Mankato, MN.  We caught up with a line of small cells on the north side of town.  They were unimpressive size wise, but they had interesting pendent shapes that curled on the southwest corner like they had small hooks.  It looked like they might be minisupercells.

  Just before we hopped on US 14, Jon spotted a pointy lowering to our northwest.  We pulled off on the onramp to the highway and jumped out to see what it was.  In the last bit of twilight we were unable to make out what it was.  Although it looked funnel like, it might have just been a pointy updraft base.

The rain moved in killing our view and our lines of cells congealed into a solid MCS.  Jon and I decided to call it a chase and start making for home.  We were in it for the long haul.  I had to be back at work the next morning, so we drove through the night, taking turns driving, Jon graciously doing most of it.


Jon and I didn’t get any tornadoes, but we had two days of photogenic storms with wall clouds.  It was a fun trip and our intercepts kept the chases from being busts, given the low tornado probabilities.


Lessons Learned: 

  • Try to clean the mud off the bottom of the van as soon as possible after driving on dirt roads.