6/24 Harland, IA Supercell

Storm near Harland, IA

Structure before storms became linear

We began today in Mobridge, SD, and today's target area was in Iowa, where the parameters for supercells and tornadoes were off the charts.  In other words, instability was so high that any storm that could break the atmospheric cap and go up would go tornadic very fast.  However, we were concerned about the convection from this morning, and we were hoping it would not mess with anything needed for storm development in the afternoon.  This meant we had to get up at 7 AM mountain time and drive 7 hours to get in position.  Along the way, we made pit stops and had a very quick lunch stop.  The models were not handling this morning's convection very well, so they were quite stingy with showing storm development.  As the day wore on, we found ourselves heading east on I-80 towards Avoca, IA.  After a pit stop/data analysis, we headed south into the town of Emerson, where we found a gas station to hang out for a while.  Eventually, the atmosphere began to boil, and it looked like the cap would hold just long enough to allow for explosive storm development.  We

More structure

decided to head north out of Emerson and stopped close to Harland, IA, where one storm tower looked like it would be "it."  Sure enough, it quickly had tops of 50,000+ feet.  At this point, we met up with the president of Tempest Tours, Martin Lisius, and his assisstant, Kim George.  Martin confidently stated, "This storm is going to produce a tornado within 30 minutes."  As we continued to follow this monster, it looked like Martin's prediction would be correct.  The storm quickly became rooted in the boundary layer and with all of the parameters lining up, a very rapidly rotating wall cloud appeared.  Unfortunately, it did not give us a tornado due to the cooler/stable air near the surface, but we stayed on this

cell for a while.  One tornado report came out of this storm, but the validity of the report remains in question, especially since hordes of chasers were on this storm and no one else reported a tornado.  As we continued our pursuit of this storm, it went through a bit of an identity crisis, if you will.  Due to the cooler stable air near the surface, tornado production quickly decreased.  Eventually, the storms became more linear, with embedded supercells.  In the end, we were treated to a nice light show before we drove to our hotel in Avoca, IA.  We drove 707 miles today.