5-5-2012 SD/NE/MN Chase

Nick and I left the Twin Cities in the early morning hours on this Saturday for a forcasted chase target near Viborg, South Dakota. The day looked on paper to be a very good tornado day in Southeast South Dakota and northeast Nebraska as a frontal boundary was to lift north into this area along with a weak developing area of low pressure also expected to ride northeast into the region by late in the day.  Supercells would be the mode of the day along with very large hail and tornadoes. 

As we drove west into South Dakota reaching Sioux Falls by 6:00am, We began to notice rapid storm development to the west of Mitchell SD which was only 1 hour to our west. With the days main event not forecast to occur until late in the day, We decided to blast west to play with these early morning storms near Mitchell being driven by strong WAA and a robust LLJ that was nosing into the area at the time. 

As we arrived in Mitchell on I-90 we began to get our first views of the coming storms as well as a quick look at the world famous Corn Palace.

 

As the storms were rapidly approaching Mitchell we were receiving upstream reports of hail up to 2.50”in diameter with the cells showing a solid and large hail core on radar. We quickly found a nice closed station with a over top canopy where we could park the vehicle to minimize damage and it began!

 

The Large hail lasted for about 5 minutes nonstop with sizes ranging from quarter size to Hen Egg size .75” – 2.00” in diameter at our location just south of Mitchell off US I-90. 

 

In some places the hail drifted up to 5 inched deep! There also was widespread vehicle damage with many windows broken in and around our area in Mitchell. 

Once these storms moved off to the northeast toward eastern SD we began to head back south to our original chase target to the southeast near Viborg. As new data came in and the morning storms putting out a robust outflow boundary to the south it became evident that we would need to move further southeast into Northeast Nebraska. 

Well as Mother Nature would have it the storms did not develop as expected as the very warm capped air held off convective development across this area for the day.