04/03/11 Explosive Iowa Supercells

A monster supercell produces a beautiful lightning show at
twilight southwest of Washington, IA last Sunday evening...

Sunday, I ended up chasing once again in Iowa. I targeted Burlington, IA as it appeared severe thunderstorms would develop very close to my target by late-afternoon and evening. This area gave me an excellent road-network to work with if by chance storms developed to my north or farther west. This wasn't the most ideal setup for tornadoes however with t/td depressions large, veering surface winds, and a strong cap in place. Hey! What else was their to do on a Sunday anyway?! The area I was targeting near Burlington, IA featured moderate instability in place with 2,000J/kg of CAPE in place, 0-6km shear near 50kts, and a surface low and trailing cold front as a lifting mechanism. The question was if we would see any convection before dark with a stout cap in place across the region. By 5:30pm, I found myself heading west of Burlington, IA on U.S. 34. I analyzed a subtle boundary ahead of the surface cold front as it passed through Des Moines, IA which looked as if it would serve to be the focus for storm initiation. This was a pre-frontal area of convergence that would later be the focus for explosive severe thunderstorm development. Sure enough the cap broke near Sigourney, IA along a theta-e ridge seen here and within a few scans this storm blasted 50,000 ft into the atmosphere. Take a look at this radar animation showing the explosive supercell development! It was amazing how fast these storms just exploded within a half hour. Anyhow, I blasted north of Mt. Pleasant, IA on U.S. 218 along with many other storm chasers. By 7:00pm, I got my first view of the supercell as I headed north of Washington, IA. This is where I observed a monster updraft and a wall cloud under the base in the northwest horizon. This was indeed a supercell with mid-level rotation and a nice tilted updraft, but where this storm struggled was with low-level rotation. It really never got close to producing a tornado in my mind, but was quite photogenic. I took some time-lapse video at this point as well and then drove back south as a new supercell developed to its southwest. I knew this would be my best play at the time. I got a view of this developing supercell as it approached Washington, IA from the southwest. By this time the sun was setting, but yet providing some excellent photo-opportunities. At this point I knew no longer was seeing a tornado even a remote possibility so I made the best of it photography-wise! This supercell would please me to no end putting out some vivid lightning and "anvil zits"! I ended up with some awesome twilight photos of this supercell and time-lapse as well which is exactly what I was hoping for out of this chase day. After nearly getting struck by lightning on more than one occasion I called it a chase and made the relatively "short" drive back to Peoria, IL. One of these days standing out in an open field photographing lightning will do me in and the headline will read "Photographer and Storm Chaser Dies Chasing Storm While Photographing Lightning" Hey, someone has to photograph lightning right?! I've added my chase photos and time-lapse video below:

Initial supercell now northwest of Washington, IA
showing off its tilted updraft and wall cloud at sunset

My first view of the developing supercell
looking northwest (wide-angle)

This was the closest this supercell
got to producing a tornado...

Amazing lightning from these storms thanks to the copious
amounts of hail these storms had suspended aloft

I punch south to find another developing supercell along the
cold front southwest of Washington, IA at sunset

A stellar cloud-to-ground lightning shot under the main updraft

Here's a YouTube time-lapse using my still photographs
of the supercell at twilight (above) Good stuff!

A great evening for lightning photography!

Another nice bolt under the updraft...

The low-level jet starts to kick in here at dusk giving this supercell
some much needed low-level shear

The wall cloud (above) would of been very hard to see if it wasn't
being illuminated by lightning constantly

I probably sat here for a good half-hour
taking photo after photo!

Traffic from U.S. 218 (right) driving right
into the wall cloud fun, fun!

Starting to lose a little more light now, but if you look close
you can still see the lowering (wall cloud)...

Yet another, lightning shot!

More lightning madness...

I really like this shot with two lightning strokes
illuminating the mesocyclone

This storm really had some weird motion going on here...
(too bad I was losing daylight) ugh!

One last shot to end on...I sure hope you
can see some rotation in that exposure!
 
I've added a YouTube time-lapse of the
two supercells I chased (above)

That's all for this post. Storm reports from this chase day can be found here. Not too bad of a chase for myself and it sure beats "blue-sky busts"! I just may find myself chasing again in the next few days and this weekend. Hey, it's April and the computer models as well as climatology says I will probably be storm chasing again before I know it...