April 3, 2014

The trough that brought us out to the plains was finally ejecting, bringing ample lift and shear across a moderately unstable warm sector on Thursday. It was forecast to occur over the less than ideal chase terrain of Missouri, however. It was on the way home though, so we were determined to make the most of the day, and chase into the depths of hilly, tree filled “Misery.” The Storm Prediction Center favored the strongly sheared setup for tornadoes with a moderate risk for tornadoes and the possibility of significant tornadoes. We decided to play the dryline/cold front where cells looked like they might be a little more discrete than the prefrontal warm sector storms, over slightly better terrain, and maturing during the peak hours of the afternoon. We also wanted to hug the surface low and stay as far north in the instability axis as we could, hoping to chase where the low level winds were more backed for better directional shear. Our initial target was Nevada, MO for an early afternoon initiation along the cold front and then we’d track northeast toward the I-70 or highway 36 corridors as storms rocketed northeast.

My stomach had been in knots overnight after having a bad snack, but I was feeling better on this morning and ready to chase. Brindley and I were rolling early in the morning, Brindley taking the wheel and stair stepping us up from southeast Kansas into western Missouri. The warm sector ahead of the front was filled with towering cumulus and the air was muggy and warm, an environment ripe for thunderstorms. We made it up to Nevada, gassing up, Brindley shooting a “local’s portrait” and then continued north to get downstream of a few cells that were just starting to appear on the radar. We got in the path of one decent looking cell near Butler, MO and watched it explode with hard convection right in front of us.

As soon as it had gone up, our storm started to fizzle. We moved east to stay ahead of it before deciding to abandon it for new development to the south. It appeared that stable air to the north, interference from rain cooled air ahead of the storm and anvil level clouds were choking our storm. To the south, however, a nice looking cell had gone severe warned and looked to maintain warm inflow. We raced back south, hoping to intercept the cell east of Nevada as it matured. In front of the storm, we had a horseshoe base and a developing wall cloud, but the storm soon entered the hilly and tree filled terrain that plagues central and southern Missouri. We paralleled the storm to the south on 54 for a while, but this storm eventually started to fall apart as well. We finally got to a point where we could head north to get in front of the storm and decided to see what the storm looked like. A large “Whale’s Mouth” had formed, the rear flanking downdraft fanning out on the south end of the storm, which would make spotting any tornadoes on the storm from a southeast position difficult or impossible. We started to drop south to get away from the base, when a cell just ahead of the gust front in the line went tornado warned. We had no visual, but decided to try and keep up with it on 54 and hopefully we could eventually get in front of it. We tracked south of the cell, moving into progressively worse terrain, until our highway eventually turned north and took us directly into the path of what was now becoming a tornado warned quasi-linear complex. We wound up in the touristy resort area of Osage Beach, with huge, steeply sloping hills, resort condos, gift shops, and lots and lots of traffic. Luckily the highway was large and fast and we made good time getting in front of the storm. We were in the path now, with no visual, however.

The sirens wailed as we drove through a populated area within the tornado warning. The sound was like music to us and had been badly missed. As we went north on the highway, Brindley spotted a gas station to the right, perched high up on top of a hill. “Up there!” Brindley shouted, and I immediately exited off the highway. The gas station provided an amazing view to the west, and we were presented with an awesome spectacle: a huge shelf cloud from the gust front of a tornado warned storm complex, rapidly approaching our position. There was a couplet embedded within the line and Brindley, looking at the velocity scans, determined that it would barely miss to our north. Brindley shot a series of photos of the shelf cloud gust front and stitched them together, creating this epic panoramic photo:

Brindley shooting the shelf:

From our perch on the hill and with the size of the storm, we had no choice but to get hit by it at this point. Our only concern was being out of the path of the embedded couplet. We’d deal with the other straight line winds.

Looking at the southern end of the gust front:

A cylindrical shaped lowering, just behind a kink in the gust front started to come into view underneath the dark base. It was exactly where Brindley said the couplet should track. “Here’s the business area,” Brindley called out. Indeed it was. If the storm were going to produce a tornado, this is the point from which it would do it. We watched the swiftly moving feature track just to our north. The motion underneath might have had some rotation to it, but it appeared to be bowing outwards more than anything. Sheets of rain whipped around underneath it with alarming speed. Traffic darted frantically in different directions trying to get to cover. Our elevated view in the bad terrain, watching the feature pass to our north, reminded us of our intercept of the Henryville, IN EF4 tornado in 2012. It had the same rush and excitement as many of our tornado intercepts. I was blown away by how dramatically the feature presented itself, “Wooow!”

The gust front hit with a blast of wind and rain and we piled into the van. Some of the other traffic crammed underneath the gas station pump cover. It didn’t seem like a good idea, as the cover offered little shelter and would just collapse on to the cars if the winds got strong enough. The winds stayed relatively modest, however, probably below severe limits.

When the rain let up enough to see the road, we departed heading north. The storms were racing off to the St. Louis metro area. Getting in front of them would require a core punch through bad terrain and we’d wind up chasing in a metro area after dark, a terribly dangerous combination. We decided to call the chase off and get some dinner, heading for home on highway 54. Mexican sounded good, and what better place to get Mexican than in Mexico. We stopped in Mexico, MO for veggie fajitas and margaritas.

After dinner, the storms had pushed off to the east, the anvil blow off covered the sky and the sun dropped below the cloud deck, lighting it up in fiery shades of orange and red. It was a beautiful end to the chase trip. We made great time heading back to Springfield, arriving just after 10.