Nokomis, IL Supercell
My tornado drought is now well over two years. I really thought in the days leading up to it, that April 28th was finally going to end the streak. The large storm system affecting most of the country had already had two let-down chasing opportunities that I passed on (you know, getting engaged, moving, having a birthday), but it looked like there would be a solid chance at some low-topped tornado producers in central Illinois during the afternoon on Monday.
Convection got under way in Missouri a little bit earlier than I had hoped. It was not long after 12 PM that severe storms were already underway well to the west. I was chasing with my dad, and my brother Wil, and had them meet at my house right around 3 PM. We quickly tossed our things in the car and headed west to intercept.
I would generally favor playing near the warm front, but storm motions this day led me astray. Further to the north, storm motion was almost straight northerly. This led to two problems. The first being the very short window that storms would actually be interacting with the warm front, and the second being that the northerly storm motion was not allowing the storms to fully utilize the good directional wind shear near the surface. Storms further to the north quickly went linear, and outflow dominant with their gust fronts quickly surging ahead killing any tornado potential.
Further to the south however, storm motions were more southwest to northeast, and this made a big difference. One storm began to get “the look” near St. Louis, and I plotted a course for us to intercept just south of Taylorville, near the town of Nokomis. The storm quickly went Tornado Warned, and we stopped quickly to empty our bladder at a gas station in Nokomis before heading off to intercept. The supercell was part of a large line and not isolated in nature, but it was clearly doing its own thing.
We got an early view of the wall cloud just south of Nokomis, and I found a spot for us to pull off and watch things organize a couple miles south of that. I was weary of the storm “turning right” and shifting to a more easterly course, so I played it safe on the south side of things so that any potential tornado would pass well to our north.
Stopping the car the inflow winds to the storm were the first thing that I noticed. The day itself had featured southeasterly surface flow at about 15-20 mph, but those surface winds were now screaming due east at about 40-50 mph right into the storm. At about the same scud began lifting into the base of the storm right in the notch, and slow broad rotation became apparent.
I tossed the camera on the tripod and began filming as the area of rotation quickly ramped up, and I became almost certain that a tornado was imminent. This area tightened up into a bowl funnel cloud, but visibility was just awful on this HP supercell, and I have no idea if the circulation ever made contact with the ground. The outflow region trailing behind the circulation quickly approached our area so we hopped into the car and bailed east.
Road options were no good, and it took us quite some time to get back ahead of the storm, not doing so until somewhere near Shelbyville, IL where a big sweeping gust front took up the entire sky.
The storm gave us one last hurrah as a little kink on the southern end of the bow echo went tornado warned as a circulation developed on the leading edge. We stopped briefly in Arcola and did see a weak fairly harmless funnel cloud which friends Brad Emel and Mark Sefried were much closer to.