May 11, 2014

Statistics

Initial Target
Start
End
Storm Intercepts
Tornadoes
Hail
Wind
Features
Miles
Fairmont, NE
Springfield, IL 5:23 AM 5/11/2014
Moline, IL 11:54 PM 5/11/2014
Clay Center to Beaver Crossing to Lincoln, NE
3
0"
0 mph
Multi-vortex Tornado, Satellite Tornado, Gustnado, Wall Cloud, RFD Core
1107

Summary

Triple point/warm front play across southeast Nebraska. Targeted Fairmont area for late afternoon tornadic supercells initiating on the triple point and riding the warm front. Intercepted severe warned supercell near Clay Center noting multivortex tornado under large bowl funnel. Escaped east trying to stay out of path and ahead of gust front. Noted gustnado interacting with updraft base near Grafton. Able to get into inflow notch north of Beaver Crossing noting later confirmed large rain wrapped tornado and satellite tornado. Chased HP gust front structure to Lincoln before heading east for home.

Crew and Equipment

Chase partners: Jennifer Brindley Ubl, Victor Gensini. Equipment: Canon 60D, Canon t2i, Canon EFS 10-22, Canon EF 50mm, Sony HDR-xr500v..

Video

Map

Details

Mother’s Day was looking like 2014’s biggest Great Plains tornado event yet. Brindley initially couldn’t chase, but her photography clients cancelled at the last second, so she was in. Victor Gensini, a met professor at the College of DuPage, teamed up with us for this run too. Victor and I both had to be back by Monday morning, so this was going to be a marathon type chase, straight to the target area, and straight back. Luckily we had three people to split the drive.

A triple point was forecast over southeast Nebraska, with a warm front bowing north into central Iowa and a dryline extending down into Kansas and Oklahoma. Strong instability in the warm sector and impressive shear profiles prompted the Storm Prediction Center to issue a moderate risk for tornadoes across southeast Nebraska, where storms interacting with the warm front were likely to produce tornadoes. Targeting was pretty straight forward on this chase, and we agreed to head toward Fairmont for ourinitial intercept point, where storms were forecast to fire by mid to late afternoon on the triple point. The only negatives to the setup appeared to be questions about storm mode and storm coverage. Would we be dealing with messy high precipitation supercells that were interfering with each other, or cyclical tornado machines riding the warm front? The morning convection cleared out early, setting the stage for a big afternoon supercell show.
I was wired up and ready to roll before dawn. The dome camera enclosure and touch screen in the predawn light:
I met up with Brindley and Victor at the Quad Cities airport and we all piled into the van and started making our way west down 80 to get into position. We made great time across Iowa and even had time to stop near our target area for lunch, finding a Subway in the tiny town of Wilbur, NE just as storms started to pop on the triple point.
A supercell went up like a bomb in the explosively unstable atmosphere. We raced west out of Wilbur for the intercept, hoping to catch the cell near Clay Center. It appeared to still be maturing and was north of the warm front, so we weren’t too worried about arriving late and missing the tornado show, figuring that the storm would need some time to root to the boundary and cycle. Besides, the storm wasn’t even tornado warned yet.

Huge Bowl Lowering
3 miles ENE of Clay Center, NE
3:52 PM
Approaching Clay Center, the horizon grew dark as if the afternoon sky was turning to night. We continued west, pushing deep into the storm’s inflow notch trying to get a view of the structure underneath. Immediately north of the warm front, the cool temperature made for extremely low bases and the moisture laden air was soupy and hazy. You had to get real close to see what was happening underneath the storm.

Just before Clay Center we turned off our county highway to watch the storm. The few trees blocking our view cleared up and we were greeted by a huge bowl lowering hanging underneath the updraft base of the storm. The sight was awesomely creepy.
We weren’t really expecting a tornado yet. The last scan of the base reflectivity showed that the hook was still north of the frontal boundary, which suggested the storm might still be elevated. Within moments of us stopping, fuzzy, wispy fingers started kicking up underneath the ground scraping bowl: a tornado. The storm still had no tornado warning.

Multi-vortex Tornado
2 miles ENE of Clay Center, NE
3:52 PM
Small condensation funnels rapidly condensed and whipped around the edge of the bowl with plumes of dust, each a small sub-vortex of one large tornado. The developing tornado is how many wedges begin, the area between the suction vortices filling in with condensation.

Victor got the updated base reflectivity scan, and the boundary was being pulled into the storm's inflow notch, a clear indication that this supercell had surface based inflow and was interacting favorably with the boundary.
The suction vortex funnels dissipated but a huge plume of dust remained underneath the large bowl. The stark contrast, low bases, and lack of reference made it very difficult to gauge the scale of the features we were looking at and our proximity to them. It was apparent we were in the path of the large bowl shaped feature, however. We’d have to immediately execute our escape route away from it. With the tornado still to our southwest, we turned east on to the county highway, blasting east to get ahead of the storm with a few other chasers behind us. Victor dashed off a report via Spotter Network of the tornado, as the storm was still not warned for tornadoes.

Once clear of the base we stopped to watch the storm from the clear air out ahead of it. Contrast was so low we couldn’t see much of what was happening underneath. We’d have to get back into the inflow notch if we were going to see anything on this supercell.

We started stair stepping east and north on the road grid trying to keep up with the storm and get our contrast back from within the inflow notch.  The storm was cycling, undergoing periods of inflow and outflow as it interacted with the frontal boundary to the south.  This cyclical supercell seemed to command the environment around itself, rather than being a subject of it.  North of the boundary, the hook would extend southward, and the storm’s impressive inflow would draw the boundary north.  As if it were alive, the storm would then take a huge inhaling breath, impressive amounts of inflow screaming into the base.  There was an eerie calm at the top of the breath, and then the storm would let it go.  Huge amounts of outflow would flood out from the storm, the rear flanking gust front surging eastward at impressive speeds.  The hook would undergo occlusion and then get drawn north back into the forward flank of the storm.  Then the process repeated.  We stepped east and north and then east and east as the RFD gust front surged and north and north as the hook occluded.  The rapidly surging RFD and turn to the left was not unlike the motion we had seen on the deadly El Reno storm last year, also a monstrous HP, and we were careful to avoid getting caught in it.


Gustnado
4 miles SW of Grafton, NE
4:17 PM
Running north near Grafton to try and get into the notch once more before the RFD overtook us, Victor spotted a debris cloud in the field to our west, a smaller circulation with a tube of dust above it. We slowed the van down to a halt to watch it and make sure we were in a safe position. The clouds above the dusty circulation seemed to swirl and twist with it, another tornado. But after a few more moments of watching it, the feature seemed to lose its connection with the base of the storm, with only turbulent motion above it. Other little dust plumes kicked up beside it and we realized we were most likely watching a gustnado, a small, brief eddy that spins up in the storm’s outflow winds. The edge of the gust front hit us with a blast of inflow, but surprisingly we were also greeted by strong vertical updraft winds. Bits of gravel and grass were coming up off the ground, flying into the van up towards the storm. The gustnado was likely being directly influenced and pulled by the storm’s updraft, stretching it vertically toward the base in a kind of gustnado-landspout hybrid tornado. We didn’t count the circulation as a tornado, but it was interesting to see its interaction with the updraft. The gust front starting to overtake us. It was obvious that we weren’t going to be able to get into the notch heading north without getting blasted by the storm, so we turned around for the next east road and started stair stepping again.

Cone Tornado
2 miles NNW of Beaver Crossing, NE
5:10 PM
The HP state of the storm persisted and for a while we debated whether or not it was elevated again, as it still appeared to be north of the warm front. We got several miles east of the storm before we hit a paved north county highway. We finally had a decent way to get back into the inflow notch without being overtaken. We raced north down the highway, passing a mean looking green rear flanking precipitation core to our west. A huge beaver tail fanned out to the north of the storm’s updraft base, the vaulted region above and behind it a sickly pea green. North of Beaver Crossing we turned east and stopped to watch the storm. We were in the notch again and could look directly into where the storm was drawing its inflow winds. The inflow winds screamed into the storm, and I had trouble opening the van’s door. Victor had gotten reports of significant damage with the storm. A tornado was likely in progress, rain wrapped within the core of the storm, but we couldn’t see it. The impressive inflow winds were all funneling into its location, however.

Then a cone tornado appeared just right of the RFD precip core. It condensed to the ground with amazing speed, probably in a couple seconds or less. It was still partially rain wrapped, but we finally had a more classic looking tornado.
The rain cleared out a bit and we had a better look at the dark the condensation funnel. Streaky bands of rain danced around it, the bars of the “bear’s cage” as it’s known, the precipitation that wraps around the supercell’s mesocyclone.
Looking southwest, two to three miles northeast of the cone tornado:

Inflow Winds
2 miles NNW of Beaver Crossing, NE
5:11 PM
The winds were screaming into the storm, not toward the tornado, however, and that got my attention. The winds were funneling into the rainy green area to the left of the tornado. Something much bigger and more menacing was lurking inside the core of the storm. I suspected that this cone tornado was actually a satellite tornado, orbiting a much larger rain wrapped tornado.

Rain Wrapped Wedge
2 miles NNW of Beaver Crossing, NE
5:11 PM
A 1.5 mile wide EF-3 was hiding in the rain. You can just make out the right edge of it in this wider angle view of the storm, the gradual slope of the condensation funnel marking the edge of a huge tornado as the small satellite moves around the edge of the bear’s cage.

The RFD region containing the large tornado was moving northeast, and while the mass was still well to our south, the forward edge was starting to get ahead of us to the east. The last thing I wanted was for this mass to overtake us, or for us to fall behind it within the core of the storm, so we escaped east out of the notch once more. We moved down the gravel as the rotating mass of rain and wind crossed behind us by about a mile or two. We cleared the core of the storm getting only a few drops of rain from the rear flank.
We were able to get well ahead of the storm using the interstate and we stopped at various exits to watch the structure behind us from the elevated off ramps. I made one last attempt to get into the inflow notch heading north at one of the exits. The huge green core loomed just to our west. It was five miles to our east road where we could get ahead of the storm, and I raced the core trying to make the road before it overtook us. We made it about a mile or so before I realized we probably weren’t going to make it. If I kept going, we’d just get run over by the storm’s mean green core, which was potentially hiding a tornado. I stopped the van and swung a U-turn and we went back to the interstate.

Ahead Of The Storm
6 miles W of Lincoln, NE
5:49 PM
The hook was becoming sloppier and the notch was filling in with rain. Getting into the inflow notch safely and with any sort of high contrast view seemed highly unlikely at this point. We caught up with I-80 and decided to use it to keep ahead of the storm and transition into more of a structure chase.

Structure
6 miles W of Lincoln, NE
5:52 PM
We went north a short ways just west of Lincoln to get a view of the structure, and we found a nice unpaved road atop a hill with a great view. The rear flanking gust front stretched to the south as a big shelf cloud with a beaver tail extending far off to the north. All the roads were lined with cars at this point, lots of chasers, but a huge number of locals out watching the storm too. A couple locals parked next to us asked if there was going to be a tornado, and I told them that there were several already and perhaps some ongoing within the storm. One of them had a shirt streaked with blood stains. Brindley asked if he was alright, fearing that he might have been injured in the storm. He apologized and explained that he had been slaughtering lambs a few hours ago.

Watching The Storm
6 miles W of Lincoln, NE
5:56 PM
Victor and I were still optimistic about seeing tornadoes at this point. We had decent visibility into the storm from the southeast, some of the best we had all day, and the inflow was still strong and warm at our location.

Perch
6 miles W of Lincoln, NE
6:12 PM
The base of the storm eventually passed to our north. We drove into a residential subdivision looking for an elevated view and got lucky. There was a gap between a couple houses atop a hill. The storm’s gust front and ominous lowering were framed above residential Lincoln.

Storm Over Lincoln
6 miles W of Lincoln, NE
6:15 PM
Brindley captures the dramatic storm over Lincoln:
The storm was falling apart and heading for metro Omaha, so we decided to call it a chase and make for home before the flanking line of storms overtook us. We departed east on I-80, Victor chatting with the College of DuPage vans as they caught up with us.

The massive numbers of spotters and chasers present in the region and the disorganizing, blob supercell:
We drove straight through to the Quad Cities to get everyone back to their cars. We made great time, and actually had time to stop so Brindley and I got a room for the night so we could get some rest before finishing the drive the next day. We had done 1100 miles in 18 hours, a personal record.
Post chase infographic, analyzing our view near Beaver Crossing, NE:

Several chasers were again impacted by this storm, which in several ways was not unlike the El Reno storm with its huge rain wrapped, HP tornado. A tour van was impacted by a large sprinkler that tipped over in severe winds within the bear’s cage, and several other chasers received damage to their vehicles as power lines came down over them within the rear flanking downdraft.

Conclusion

This chase was a big success for us. Our target verified nicely and we were able to intercept a few decent tornadoes. Ultimately the HP storm made this a very difficult, dangerous even, chase, and kept the tornadoes from being more photogenic. Perhaps if the storm could have anchored to the warm front and rooted to the warm moist inflow south of it instead of transitioning between elevated, outflow dominant states between cycles north of the front, this storm might have been a more visible classic supercell. We were able to safely play the inflow notch on this storm, but we had to be on our toes to take our escape routes to avoid the RFD core with rain wrapped tornadoes and RFD gust front, which several chasers got caught in resulting in damage to their vehicles. The large rain wrapped tornado tracked from Cordova to east of Beaver Crossing, was rated EF-3 and had a maximum width of 1.5 miles, making it very large, yet difficult to see wedge tornado.

Lessons Learned


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