6/11/2008 - East Nebraska HPs and Louisville Tornado

A number of ingredients came together on Wednesday to produce a rather significant severe weather outbreak in the Kansas-Nebraska-Iowa region. A strong upper-level trough, surface cold front, moderate to extreme instability, and rather nice bulk shear produced a line of supercells with a number of rain-wrapped tornadoes, including the tornado that produced the tragedy at the Little Sioux Boy Scout camp in Iowa.

We awoke in Oacama, SD that morning to a forecast target of the Fremont, NE area (just northwest of Omaha). Upon arrival to our target, I enjoyed the developing cu with a nice chocolate milkshake from Sonic. Eventually, a number of cells developed from Sioux City, IA, to Seward, NE. We watched as the cells appeared to struggle against a stout cap in the Fremont area. Eventually a cell just north of Fremont got its act together. However, it quickly moved to the northeast and became shrouded in precip … we let it go and focused our attention on a cell that was gathering strength between Seward and Wahoo. Little did we know, that initial cell that we let go northeast of Fremont went on to produce the rain-wrapped Little Sioux tornado that killed the four scouts. Tragic.

Initial storm northeast of Fremont, NE ... this storm went on to produce the tornado that killed the four Boy Scouts in Iowa.

Storm-relative velocity (left) and base reflectivity (right) at the approximate time the storm moved across the Boy Scout camp. Circulation was clearly evident in the velocity product, but rain-wrapped. I remember telling my brother at this point (while we were chasing in the Omaha area) that there has to be a tornado embedded in the precip. Unfortunately, I was correct.

We arrived to our cell of interest near Mead, NE where we watched a rather large wall cloud with moderate rotation slowly meander toward the northeast. We followed this storm toward the north Omaha area, but we didn't witness the confirmed touchdown 6 n of Elkhorn, NE

Storm near Mead, NE.

My brother taking some pics.

HP supercell wraps up and heads toward northwest Omaha (shot 2 miles sw of Elkhorn, looking north). A few minutes later this produced a tornado, though we couldn't confirm anything from our vantage point.

We eventually broke off from that storm and wrapped around north Omaha, through Council Bluffs, back through the south side of Omaha, toward a new mesocylclone forming along the line over I-80 between Lincoln and Omaha. We got to the storm as it was closing in on us near I-80 and sr-50, where we quickly blasted south to stay ahead of it. We stopped on a hill crest south of Louisville, NE, where we overlooked a quickly forming kink near Ashland. This kink produced a brief dust whirl – and confirmed tornado – as it wrapped up just to the west of us.

Confirmed tornado to the left of the lightning strike (this would be the tornado that was confirmed by the NWS 3 mi sw of Louisville, NE). Click here for an animation of this setting illustrating the large amount of rotation, and dusty tornado. Also, check out Blake Naftel's youtube video of this tornado here. This was yet another tornado caught along a "kink" in a line -- unfortunately, these types of tornadoes often lack a nice condensation funnel.

Typical view along the flank of these supercellular lines.

Eventually that kink wrapped up and we headed south … quickly! … as the wet RFD surged toward us. We finally broke out of the heavy precip at Manley, where we blasted east. This surge followed us all the way to Plattsmouth, where we saw yet another kink – with supposed tornado – wrap up just north of town. As the sun set, we headed back into the storm toward Lincoln, where we nighted at a Holiday Inn Express on the southeast side of town.

Tough day as we had to deal with fast moving storms, rain-wrapped circulations, chasing in a major metropolitan area at rush hour, and closed roads.