May 8, 2014

May 8 was supposed to be main the day of my two day run to Minnesota, and one of the first great looking setups over decent terrain for the season. A warm front was forecast to bow north over southern Minnesota, with a dryline and cold front extending southwest out of Sioux Falls. Storms were forecast to initiate by afternoon in an arc down the dryline, mature into supercells across the warm sector, and produce tornadoes as they approached the warm front. My initial target was the Blue Earth, MN area as the warm front looked to be just north of there by mid afternoon and I hoped to catch storms coming off the dryline/cold front intersection just south of the warm front triple point.

I had camped in the van overnight near Mankato. A morning MCS tracked east across the area with some thunder and heavy rains. There was quite a bit of uncertainty as to how this early activity might influence the setup later, especially how much negative impact it would have. I met up with Rob Hurkes, James Seitz, and a few other chasers in Blue Earth and we awaited initiation while a local reporter stopped by to ask us some questions.

Blue Earth was raked by an elevated MCS during the early afternoon so I decided the main play still had to be west, closer to the boundaries where the sun was out and the warm sector wasn't completely worked over. I moved west down the highway a ways. A storm popped right on the triple point and was initially elevated north of the boundary, but appeared to be organizing rapidly and interacting with the boundary. This looked to be the storm of the day. If it could root to the boundary and start ingesting warm moist inflow at the surface, it would probably turn into a cyclical tornado machine. I blasted west down 90 for the intercept while smaller storms were going up over my head right on the warm front. I turned north at Luverne for the intercept. The western horizon grew dark as night with the approach of the storm giving me creepy chills. There was little structure under the storm, only a dark fuzzy updraft base. There did appear to be some sort of tail cloud forming just to my west though. I turned east a few miles north of town, where the inflow notch of the storm should hav been. I got out of the van to survey what was going on and was immediately hit by a bone chilling cold wind. The storm was dumping massive amounts of cold outflow, when it should have been sucking in warm moist air where I was standing. It was not a good sign. Sure enough, I could see a faint boundary ahead of the storm on base reflectivity. It was north of the front and its own outflow boundary in the cold air. The boundary was visible to my south, a ring of cloud of debris and cumulus ahead of the storm to the south and east where the sun was out. After only a few minutes after I had gotten on it, I bailed on the storm as it had no chance of producing and raced back south to 90 to head east toward the little cells I had seen popping near the warm front.

It was too late though. One of the tiny cells had managed to mature before it crossed the warm front and became elevated ,and it squeaked out a brief tornado right on the warm front. It was about the only tornado play for the day. The rest of the cells quickly became elevated as they raced across the warm sector, or struggled against weak lapse rates and worked over air in the warm sector and failed to mature.

I returned to Blue Earth to make sure newer developments in the warm sector across northern Iowa wouldn't pull any more surprise tornadoes, but it was hopeless at that point and the chances for supercells and tornadoes were rapidly diminishing by sunset. I called it a bust and started heading for home by about 7.