It could happen tomorrow, two years ago...

[Chad Cowan]

Yesterday marked the two year anniversary of one of the most intense, non-chase weather days of my life when a tornadic derecho tore through downtown Chicago, where I was living at the time. I filmed a funnel cloud/ mesovortex over the Sears Tower from my rooftop, looking south over the city, and then was treated to an incredible CG barrage and another mesovortex/spinny-cloud-thing (photo) over downtown from a storm that fired on the derecho's outflow boundary.

The 0z ILX (central Illinois) sounding that evening showed over 8,000 j/kg of CAPE! I remember the analog for that sounding was ILX's sounding from August 28, 1990, the day of the Plainfield, IL F5 tornado, which struck less than 40 miles from Chicago. The 2008 derecho produced five tornadoes, with (IIRC) a couple of them being rated EF-2, which is very strong for LEWP/mesovortex tornadoes. There was also a 92 mph wind gust recorded by a buoy a couple miles off the shores of Lake Michigan.

Video:
http://www.youtube.com/watch?v=jSJiucjn7GA

 

[Stephen Locke]

I find it exhilarating and a little unnerving to be way up in a tall building during a storm like that. Once upon a time I was at the top of the Reunion Tower in Dallas, TX when a highly electrified bow echo moved through. One really gets a sense of being suspended up in the storm. Your video reminded me of that experience.

 

[Adam Lucio]

Ill never forget that storm, my video here as the power gets taken out in my neighborhood.



That day was also the first time I have heard the sirens go off at home in many years...theyve gone off before but I seem to be good at not being there. Some spotter I am lol.

Interestingly enough another derecho struck on Aug 4th of this year, but it was in the morning and much weaker, however the complex began to strengthen over the city and went on to produce widespread damage and unfortunately 4 deaths.

Every year in August I say it "its time for our yearly derecho."

 

[Danny Neal]

- Derecho moving in from the WNW on the south side of Chicago


Derecho hits..... it was so amazing to hear that roar with tornado sirens!

 

[MatthewCarman]

For those of you interested here is the NWS Hotseat Scenario of the event: http://www.srh.noaa.gov/ffc/HotSeat/...patrick01.html

 

[Jason Foster]

Chad, that is a cool video. The first part reminded me of a few movie scenes, particularly Blade Runner. I do wish it actually happened more often, I'd actually consider living in a major downtown city more if this was common.