Day 2 into Iowa

Day 2, 682 km through Iowa, into Nebraska.

The day started with analysis of maps from weather models, with students split into 3 chase groups. We studied maps and compiled Miller analysis charts for an hour then each group presented the analysis with target areas of choice, two of them, where we were interested in chasing. All three groups were in pretty good agreement about the areas, and we started off toward the east of Northern Nebraska, near the border with Iowa. After the gas/lunch stop along the highway, we headed east toward an possible intercept area. There were a few very discrete cells with high moisture content and high tops, moving northwest to southeast and we were aiming to see storms developing as, hopefully, the cap lifted, because the CAPE and shear were high and the existing cells were energetic. Just north of us as we got to an area near Westpoint, and pulled off on a gravel road between a corn field (~knee high) and a field of 6” soybean plants. The local traffic was interested in why we were stopped and hoped there were no storms as they've had enough, but they wished us luck. We watched altocumulus castellanus clouds forming and trying to grow out of scattered small cumulus visible on the satellite loop, for an hour or so in growing heat. It was good practice for time-lapse imaging on cell phones and cameras. The buildups kept getting sheared off early, although they looked like they ‘wanted to’. So we drove to Westpoint for ice-cream and to wait for the cap to move off, temps to build and let the instability grow. 

The DQ visit was full of fruitful blizzards (and welcome AC) with good conversations with some locals about “good storms” for us being “bad weather” for farms and folks in the area. We adjourned to the local park and waited in the shade, on swings, and on walkabouts with a close eye on developments in the sky. A new-found four leaf clover in hand, we took a group photo clustered around the tank on display, and headed back to the northwest a short distance to rolling countryside and stopped to watch the sky. Now clouds were building much higher and after seeing some really good castellanus formations merging we loaded in vans. Shortly up 5he hill, we saw a pileus formation on top of one tower, and the a second layer on top of that. A small bit of ‘cauliflower’ poked through the first pileus layer, and as a third layer formed further up, the buildup poked through the second pileus layer and spread back a bit downwind. This was the area where a small wall cloud seemed visible in the distance  under the base of far-away cloud, earlier when we were watching from lower in the pasture area. The instability was poking through the cap! So we barrelled back to the highway and crossed over the very full Missouri river into eastern Iowa, found a turnoff away from wires and set up gain along the edge of the road and in a nearby field. 

On the short drive, the radar had showed a bit of a hook echo marking rotation, and there was a hail report. The storm was now definitely a STORM, and the anvil was growing back to the northwest overhead. Between crepuscular rays to the north the south edge of the anvil, there was a rain shaft with foot developing, and the in the lower, dark area under the storm, a wall cloud developed and dark flanges of it definitely showed rotation. There were oh so many projections down, around its circumference but no funnel... inflow was so prominent and a really prominent beaver tail-like structure projecting under the storm from the south feeding into it from beneath. The storm was cycling between growing stronger and weakening as the rotation appeared the wear out and the wall cloud disappeared, so it wasn't able to really sustain the energy to make a tornado. As the wind outflow came past us and rain was starting, we loaded tripods, cameras, and ourselves back into vehicles, and shifted position to the south and east. We'd so wanted to see a funnel, but alas, it was not to happen!

Again we found a turnoff between quiet corn fields, and set up to watch another newer cell build higher and higher in the sinking sunlight. The colours were beautiful inside the storm, seen between lower-level dark cloud n the shadow of the anvil. With lovely crepuscular rays, the opposite side of the sky, just on the south edge of the storm showed anti-crepuscular rays just beside the rain shaft. Each new ‘generation’ of ‘cauliflowers’ building in the new cell was first white-white, then a rich shade of pale buttery yellow, then golden, as it rose rapidly (easily seen, even without aid of time-lapse). Again, there were new storms building to the northwest, anvils showing pinkish in the distance, but although there was an area of “disks” under the cell we were under with some slight rotation, the storm wasn't building high enough. The mosquitoes started to annoy as we loaded up again, and headed for dinner at the Icehouse sports grill in Omaha. It was great to eat on the patio as it got dark and the draft was tasty, mixed in with delicious chatter about the chase and storm-cloud observations. People posted time-lapse videos and tweated, and we headed out. It was 12:30 when we got to the motel for O/N in Lincoln Nebraska. Overnight  there was really severe wind in the major thunderstorms that poured on Lincoln and surrounds that night.  A great day of learning with real-time observational input — living the data!! Judy Anderson