Dryline setup across central SD and northern NE.  Chased with Jennifer Brindley targeting Mitchell, SD for afternoon supercell initiation.  Chased weak radar return/shower north of I-90 but let it go after it after an hour when it failed to organize and raced away faster than we could keep up.  Turned around and went after mature, tornado warned supercells coming out of NE into southern SD.  Intercepted near Tripp, SD noting large supercell gust front and gustnadoes before storm lined out.  Targeted HP supercell west of town as it became tornado warned, with dramatic structure within inflow notch.  Briefly caught in core, but pulled ahead of fast, eastward moving cell noting several large, dramatic gustnadoes.  Fell behind storm so called it a chase and headed for home, with a marathon overnight drive.

Chase partners: Jennifer Brindley.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Millenicom 760 USB datacard and cradlepoint router, Holux 236 GPS, Robotic camera dome with Sony XR-520V. Canon 60D and EF-S 10-22mm

Photography courtesy: Jennifer Brindley

Memorial Day weekend is probably the peak of chase season.  If there is a setup anywhere in the plains or Midwest, you go after it.  There was a nice setup this year, but unfortunately, it was on Monday, in South Dakota, and I had to be at work on Tuesday.  Jennifer Brindley, who was quickly becoming my regular chase partner, wanted to team up for the chase, and agreed to help make the marathon overnight drive Monday night so I could get back to work. 

A nice dryline was forecast to extend from the ND/SD border southwest into central NE with a shortwave trough ejecting over it.  The warm front up on the ND/SD/MN corner looked like it could be a potential tornado play with the better directional shear and dewpoint spreads.  The cap was stronger up there, however.  Into Nebraska, hot surface temperatures made for a significant dewpoint depression, but would weaken the cap.  The dryline was closer to the ejecting trough so initiation looked more likely there as well.  Based on model guidance, which showed the cap weakening by late afternoon across central SD with a nice mix of shear and instability, we decided to straddle the two targets and make for east central SD, with an initial target of Mitchell, SD.

I packed the van and left the house the day before, picking up Brindley in Milwaukee and making for Minnesota via 90.  We stopped in Albert Lea for the night, slept in and headed into South Dakota late next morning.  Brindley stubbed her toe getting up in the middle of the night in the hotel room, so we stopped to get some pain meds.  I asked if she wanted to head back, but she didn’t so we continued on.  Seeing a doctor after the chase, it turned out that her toe was broken.  After grabbing some lunch in Sioux Falls, we made for our target of Mitchell, which featured a strong instability and shear combination, and high resolution models indicated storms initiating later. 

Several miles south of Arlington, SD our pursuit came to an end, however.  The highway was under water.   

The map even indicated that it was a section of road that flooded with what looked like a lake plotted on top of it.  The water didn’t look that deep, and we could have probably made it if we attempted to ford it. 

  We raced south down 81 toward the Nebraska border.  It took us a couple hours to make it down there, but the storms held together, maintaining their tornado warnings.  Cutting west toward Wagner, SD we got our first view of the storm.  There was a large bowing gust front extending out from the eastern flank of the storm.  To the northeast a large dust plume was being kicked up.  It looked like it was in a more favorable area for tornadogenesis, but it appeared more like the rear flanking downdraft was kicking it up dust rather than a tornado debris cloud. 

We went north to to keep up with the storms, but they soon lined out with just a lot of fast moving scud.  I thought our chase might be over so we stopped for gas in Parkston and checked radar. 

We headed southwest out of town a couple miles and sure enough, a dramatic rear flanking gust front with deep green precipitation core came into view.  The inflow notch deepened and the storm took on much more of a high precipitation hook echo appearance on radar.  I guessed that there was impending tornado warning, and within a couple minutes we had it. 

We lingered watching the churning gust front and green core, hoping to catch a developing tornado before we had to move.  We were in the perfect position to catch one on a high precipitation storm. 

The storm’s inflow notch seemed to swallow us.  Massive green walls surrounded us on all sides and the day turned to night, yet it wasn’t even raining yet.  It was like we were going deeper and deeper into a cave. 

As Brindley and I shot a few stills using our tripods to steady the cameras in the low light, I heard thud off to my right.  Just as I realized what it was, I heard a whistling through the air and a second thud much closer.  It was hail, very big hail.  “Get in the van!” I shouted again for the second time that day.  We had lingered too long and now we had to get out of the inflow notch before we were completely swallowed in the massively severe, possibly tornadic core.  The inflow notch extended to the northeast and our road went east, however. 

The rear flanking core caught us as we got back to Parkston.  I could barely see the road, and had to dodge a pickup as we came out of an intersection.  Despite the blinding rain, we had to pull ahead of the storm to get back out into the clear air, or else we’d fall behind and lose our position permanently or wind up in a more dangerous part of the storm.

We raced east out of Parkston on 44.  Through the driving rain and hail we could see the end of the tunnel.  The eastern horizon brightened and we could see clear air in the distance.  Once outside of the core, we found ourselves driving underneath the gust front. 

The gustnado became so large, the dust pulling up to the base of the storm, that I did a double take and thought we might actually be looking at a supercellular tornado.  The large brown bowl of dirt looked a lot like the developing Mapleton tornado. 

We chased the gustnado for several minutes.  At close range and with its size, it was more dramatic than many smaller, but real tornadoes I had seen from a distance. 

The storm maintained its tornado warning, with a nice hook.  We made a vain attempt to get back into the inflow notch, but the cell, moving northeast at speeds approaching 60 mph, could not be caught.  We stair stepped up various highways until we reached I-90 south of Montrose, SD before we realized that we were making no ground on the storm.  It was 8:30 pm and I had to be at work the next morning, so we decided we better call it a chase.  We let the storm go and turned on I-90 east and started the long journey home.  We stopped for grub and gas in Sioux Falls, and stopped again in western MN just after dark to see if we could get a few lightning photos off what was now a mature squall line behind us.  The storms were collapsing and gusting out, however, so the lightning shots were slim pickings.  We made good timing driving straight through the night.  Brindley took over and drove during the wee morning hours until we got to Milwaukee, and I was able to take a nap and make it to work on time.  I was a complete zombie that day in the office, but I was glad I chased.

We had a one day marathon trip to South Dakota that didn’t bag us any tornadoes.  I thought we had missed the show when we came in late to the storms coming out of Nebraska.  The initial tornado reports were most likely similar gustnadoes to what we had seen later, however.  The gustnadoes we saw that day were just as dramatic as some of the actual tornadoes I’ve seen and along with the impressive storm structure, it was an exciting and rewarding chase.  The little blip we chased toward the warm front wound up never amounting much and the warm front target busted in general.

This was also the last time out for the “Mudpuppy” as my regular chase vehicle.  After tens of thousands of miles and over fifty tornadoes, it had been a great chase vehicle.  It was rapidly falling apart by this point, with 250,000 miles it needed new struts, exhaust, brakes, and A/C.  The windshield was still cracked in two places, the transmission was causing a vibration, and now it was out a side mirror after the 5/25 chase.  I wound up replacing the van a couple weeks later with a 2010 Town and Country.  I got a hail damage discount from a dealer in southern MO.  The new van was damaged by the very same storm we chased on 5/25.  The dimples on the body were barely noticeable and probably insignificant as to what will be added over its life as my new chase vehicle.

Lessons Learned: 

• Don’t linger too long in the inflow notch of an HP supercell.

• Large gustnadoes can be just as dramatic as small tornadoes.