April 15, 2012

Statistics:

Initial Target: Albert Lea, MN
Departure: Junction City, KS 8:00 am
Arrival: Westchester, IL 3:00 am
Intercepts: Conger, MN
Tornadoes: 0
Hail: None
Wind: Non-Severe (not measured)
Features: Update Base
Miles: 915

Summary:

Fourth day in a plains run with Brad Goddard and Jennifer Brindley Ubl. Targeted trailing dryline/coldfront in south central MN for afternoon initiation of supercells. Surface winds remained veered and small, subsevere storms were all that materialized. Had dinner in Albert Lea before intercept sub severe storms southwest of town, noting nice contrast, colors, and well defined updraft bases. Headed south toward home after cells passed to the north, passing more cells and a nice rainbow, arriving home early in the morning.

Crew and Equipment:

Chase partners: Jennifer Brindley and Brad Goddard.  Equipment:  Kenwood TH-F6A Tribander, Dell Inspiron Laptop.  Millenicom 760 USB datacard and cradlepoint router, Holux 236 GPS, Canon 60D and EF-S 10-22mm

Photography courtesy: Jennifer Brindley

Video:

 

Details:

Sunday was the last day of a four day plains run with Brad Goddard and Jennifer Brindley Ubl.  After chasing a tornado outbreak the day before across central Kansas, the weather system was moving east and we were hoping to chase it home.  An impressive 100+ knot midlevel jet was ejecting across the upper MS valley, with a warm front across central MN, and a dryline/coldfront extending from a surface low along the SD/MN border.  Despite modest to marginal forecast instability across the warm sector, the very impressive shear profiles prompted the Storm Prediction Center to issue a moderate risk for tornadoes across southern Minnesota, northern Iowa, and into Wisconsin.

The best shot for tornadoes looked like it was going to be right on the warm front across central Minnesota and east into Wisconsin.  A few problems existed with this target which kept us from racing out to it.  Forecast instability dropped off the further north you went and was expected to be pretty paltry right on the warm front.  The terrain in east central Minnesota is also less than desirable, with the Minneapolis metro being unchaseable and the surrounding areas with trees and lakes.  In addition, we had put in thousands of miles the past few days and we were just too exhausted to go to the ends of the Earth again on a fourth day.  We decided to play down the dryline/cold front where storms were expected to be a bit more discrete, over open terrain, and with a more favorable NE motion than northerly by the warm front.

We were rolling from Junction City, KS bright and early, heading through Kansas City and then up to Des Moines on 35.  Watching the surface observations, about half way to our target it started to become pretty clear that we weren’t going to see a tornado by not playing the warm front target.  Surface winds were originally forecast to be out of the southeast, or backed.  They had veered badly, however and were all out of the southwest.  The change in direction ruined our beautiful shear profiles and meant we’d probably be dealing with a linear storm mode.  Coupled with the lack of instability, it didn’t look like we’d be seeing much of anything now.

Still SPC stuck to their forecast, maintaining the threat for tornadoes, and convective models showed rotating updrafts across south central Minnesota, so we continued on.  Arriving in Albert Lea, a mess of low topped storms had gone up by the warm front, a couple of them produced tornadoes, but dozens of cells surrounding them did not.  The cold front was way off to our west but was starting to light up with a few return on the radar.  It would take some time for those storms to get going and come to us so we decided to stop and have a steak dinner to celebrate our successful tornado intercept from the day before.

We could see towers trying to go up from the Applebee's windows, so after dinner we headed west down 90 a few miles and stopped in front of a line of cells that was racing north. I was surprised to see well defined updraft bases on the low topped showers. They were moving so fast, however, that we decided to let the cells come to us and pass by rather than pursuing after them.
We dropped south a couple miles onto the gravel and let the next cell approach. The low sun made for some dramatic contrast and color. Little more than subsevere showers, these storms were some of the most photogenic we had seen the entire trip.
As our next cell approached, a large block of scud started to condense underneath the base. From a distance it might have looked like a funnel, but there was only slow, rising motion associated with the feature. A neat looking scud funnel:
The little storm pulled more scud into the base in what looked like an attempt at a wall cloud:
A little clear slot even formed behind it:
Cell passing by to the west:
Brad and I shoot the storm as it passes by:
For once on the trip we got to just sit and watch a storm go instead of racing around frantically trying to keep up. It was a gorgeous storm too. Brad and Jenn sit on the road, taking in the sights:
After the last cell in the line sailed by with no hint of severe weather or even lightning, we decided to call it a trip and head for home. We passed a few more cells in northern Iowa as we headed south down 35. A bright rainbow formed on the back end of one of them and we pulled off the interstate to shoot it while it lasted:

It was a long, overnight drive home, stopping near the Quad Cities to drop Brad off before making it back to Westchester, Jenn driving herself home from there.

Conclusion:

A few tornado reports came in on the warm front, and a few more on the cold core side of the setup in Nebraska. They were brief, needle in the haystack type tornadoes, where one would have to be extremely lucky and pick the right cell in order to get them. We figured the day would not live up to the hype of a strong tornado outbreak when we saw the surface winds veering south of the warm front and the instability failing to materialize. Encountering no real supercell structure or any severe weather, the chase was technically a bust. We still encountered some gorgeous convection, however, and it was a photogenic end to our exciting four day to plains run, so we were happy we made the detour north into Minnesota on the way home.

 

Lessons Learned: 

  • When the surface low elongates and surface winds veer, the only play for tornadoes may be on the warm front or cold core end of a setup.

  • Subsevere cold front showers can still be very photogenic.