6/18/2010 -- MCS Shelf Fest

Awoke in Waterloo, IA to storms already ongoing and coalescing across west-central Iowa -- not a good sign for potential tornadic supercell development for later that evening thanks the squeegee effect of MCSs. I had no other choice but to follow this stuff home, so I jumped on the "shelf" train near Marengo, IA.

Shelf comes into focus west of Iowa City.

Shelf along I-80. If you click on the image, you'll see a tiny black dot along the edge of the shelf. That is an old school plane -- I was speechless as I watched the guy/gal literally hug the shelf as he/she moved south. Bet that was a hell of a view!

Panoramic shot.

Another pany shot.

I essentially let this thing tail me all the way to DeKalb, IL. The shelf along the derecho in Illinois was not as dramatic as it was in Iowa. Made it home to say hello to Sharon and Chase as the storms swept through -- producing some moderate tree damage and power outages. Appears as though the gusts were in the 55-65 mph range based on some of the limb/tree debris around my neighborhood.

Since it was still early in the day, I decided to head back west towards the Quad Cities area where a northward surging outflow boundary was straddling the IA/MO border. The best area of convergence along this boundary was southwest of Des Moines, which was problematic in terms of timing (at least for me to get there before nightfall). Instead, I went to Quad Cities with (1) the hope that the storms to the southwest of Des Moines would move into southeast Iowa before sunset (thus making them catchable), (2) hope for new development along the outflow in extreme southeast Iowa (towering cu formed but eventually dissipated), or (3) intercept another MCS forming in elevated air across northeast IA. Well, option (3) was it once I determined the storms from option (1) were not looking good on radar (outflow dominant) and option (2) was squelched by a cap, meager convergence, and lackluster sb-CAPE. Option (3) afforded me the opportunity to sit down and have a nice Chick-fil-a dinner while awaiting the MCS to my north. After dinner complete with a Polynesian-Chick-fil-a sauce mix, I slid east to Port Byron along the Mississippi River, where I setup for some timelapse of the oncoming shelf. Boy, this shelf did not disappoint! It was spectacular and even featured a unique rainbow along the entire horizontal length of the shelf (a bit hard to discern in the photos/gif animations, but hopefully you can see it). Scooted east out of town as the thing ran over the top of me ... the race was on. I let it tail me all the way to Sheffield, IL, where I finally called it a chase and headed home to DeKalb. I'm not overly fond of MCS chasing (dominant storm morphology we get across the Midwest in the summer), but this storm was quite picturesque.

Shelf rears its head on the Ol' Miss-- oh, you should've seen the boaters squirm! BTW, Port Byron sounded their sirens despite no tor-warn. Actually, a lot of towns I traversed this evening sounded sirens.

Shelf approaches Port Byron. The crossing sign you see there must've been blown down by the first MCS of the day. In fact, crews were repairing felled power poles in town as I was looking for a place to setup shop.

Panoramic of shelf over the Mississippi River.

I have a number of gif animations, but I'll only provide one within the blog below so as not to overload those with slow connections. Those that are interested, can view the other gif animations via this directory.

Port Byron shelf. Can you see that rainbow effect within the shelf? Not sure the camera (or my amateur photography) does it justice. Twas cool.

I hope to update with some timelapse video in the near future ... check back in a few days.