We have been seeing amazingly rapid supercell growth of two cells, one just north of Guernsey and a second near Lusk since 2045Z.  Both cells have also shown rapidly increasing severe probabilities.  The Overshooting Tops algorithm was also indicated with the Lusk cell.

The 1-minute GOES-14 visible satellite is showing both supercells very well (L).  The two pink overlays indicate the increasing severe probabilities.  The southern cell north of Guernsey was up to 90 percent, while the cell near Lusk was at 76 percent.  Since 2107Z, the Lusk cell severe probabilities increased to 89 percent at 2110Z. along with several CG lightning strokes.  The 2107Z Flash Density (R) was up to 17/minute with the Gurensey cell, and 10/minute with the Lusk cell.

CoonieCatEye/MacGyver