2014--Day 7

An interesting day...so much so that I'm writing this on the next day (thanks to Gustavo and his reunion with his drivers license).  It started late (per usual) in Aberdeen.  Gus and I were discussing this earlier, as I'd said it's a good thing we're not firemen (we don't get going quickly enough in the morning).  To our credit, it's much simpler with two (as opposed to 12+--students do add to the experience wonderfully, though), and we've been fortunate to be close enough to the action for the next day.  Nevertheless, we still manage about 400 miles a day.

Looking at the data, it became apparent that the instability was there--CAPE values in some locations were around 7000 J/kg, easily the highest values I've ever personally experienced.  The shear, however, was another matter, appearing to be better organized to the south and slightly west of Aberdeen.  The synoptic setup had an inverted trough intersecting a modest frontal system (a triple point of sorts) in Nebraska, progged to move slowly north and east. 





1.21 gigawatts!  I mean 7000 J/hg!



Note the location of the triple point...

As such, we gassed up (both the car and ourselves) and headed for Mitchell (home of the Corn Palace)...and waited.  For three hours.  THREE (blessed) HOURS.  It was long enough for two bathroom breaks (thank you for the clean facilities, County Fair) and a snack (again, thanks County Fair).  In fact, we waited for the SPC to issue a watch that had been advertised in a previously issued mesoscale discussion.  Said (tornado) watch was issued at 6:25 pm local.  We examined some derived soundings for Mitchell and saw a 5 degree C cap over the area.  7000 J/kg does no good if the cap is too strong.  As such, we headed west and north to chase a potential storm on the southern end of a line. 

We headed north on US281.  This turned out to be a popular option, as we passed a number of chasers along the way.  At one point the Tornado Intercept Vehicle (The Dominator) passed us.  Again, we played the waiting game as the storm passed to our north, which eventually had a tornado warning issued for it.  This particular storm passed through the town of Wessington Springs (population ~850), and did significant damage.  Fortunately, only two people were injured, but 10 businesses suffered damage (five extensively), and at least 25 of the 43 houses that sustained damage were rendered uninhabitable. The official damage survey indicated an EF2 rating.

Look at the anvil on this!

Around 8 pm local we were located near US281 and 236th street, south of the towns of Lane and Alpena.  It was here that we first saw TWO tornadoes on the ground just to the east of US281: the main funnel to the west, and a rope tornado to the east.  The latter did not last for very long, but we were able to chase the main tornado for at least 25 minutes.  It appeared to rope out and reintensify at least once or twice while we chased it. 

Jackpot!

Come on down...

Twins!

Look closely...

Lightning bookended by tornadoes!

Wedge and rope

Just (!) a wedge

Flanking line

Stovepipe tornado

Beautiful structure

A big one!

Losing weight

Thinning...

...and thinning some more

Making a comeback

Coming back to a wedge

Looking good!

In ground contact?

Perhaps.

It went from this...

...to this in 75 seconds.

Roping out?

Looks that way.

Twisty

Anorexic

Get bent.

Or not.

The little tornado that (still) could!

One happy geek!

Two happy geeks!

Anvil mammatus

Your mam(m)a

Still going...

Nearly 30 minutes after the first sightning!

A thing of beauty

The last.

After this tornado petered out, we turned our attention to a supercell that had just split into right- and left-movers.  Oddly enough, the left-moving storm turned out to be the dominant storm (just for you, Leah Smeltzer).  We chased this storm north through Huron, and while it had a well-defined wall cloud, it tried but failed to produce more than a couple of funnel clouds.  While we waited by the side of the road with our blinkers on, no fewer than three cars stopped to see if we were OK (we were).  Very friendly people, South Dakotans.  By this time, it was getting too dark to see (the funnel clouds were only visible by lightning), so we turned around and headed south. 

This one's for Leah.

Our original plan was to head back to Mitchell, but apparently the Corn Palace is such an attraction that it drives hotel prices as high as an elephant's eye.  A quick investigation of Huron hotels produced fruit, and after a visit to the palace for a late dinner, we found our hotel quickly.  The gas station across the street had a pleasant surprise for us, and of course we had to be total geek fanboys.

Bet we got better gas mileage...

This is #3.

Lessons learned:

1. Inverted troughs can be your friend.

2. Especially when they form a triple point with other boundaries.

3. All the CAPE in the world doesn't mean a damn thing if the cap is too strong.

4. If we hadn't waited all that time in the County Fair parking lot, we might not have been in the right place at the right time.

5. This Dominator is registered in Saskatchewan.  Perhaps they refuel at Corner Gas and have a bite at The Ruby whenever they pass through Dog River.

All in all, a great day: 362 miles (short by our standards) and two tornadoes.