2015-08-02 Event: IA

[JeremyS]

Crazy videos from a beautiful tornado in southwest Iowa tonight. Will be interesting to see what it is rated. Sucks to miss the ones that are so close, only about 2 hours away from my home!

http://www.ketv.com/news/video-tornado-spotted-near-williamson-iowa/34499396

 

[Jeff Duda]

Sad to say, but that's one of the most beautiful tornadoes I think has occurred in Iowa in recent times. Just goes to show meteorology as a science has a ways to go still with predicting storm-scale details that make the difference between a marginal supercell and a high-visibility, high-contrast tornadic supercell like this. I didn't see much in the way of low-level shear in that area. However, there was something of a front, but it looked kind of weak. There was definitely tons of CAPE, probably resulting from moisture pooling along the front.

 

[Dan Robinson]

I studied the satellite and radar loops leading up to this afternoon, and there were not any boundaries apparent in the vicinity other than the approaching cold front far to the northwest. The storm developed a thin appendage on the northwest flank, then seemed to tighten up rapidly once it ingested/merged with a smaller cell to its west. The storms were moving SE but backbuilding to the NW in a Jarrell-esque manner. There wasn't even a noticeable kink in the cold front that would have pointed to this happening where it did. The storms went up about 20 miles south of the cold front's visible radar echo - clearly forced by the front, but not interacting directly with it at the surface. As Jeff said, clearly the strong CAPE had a lot to do with it. The storm ingested something and made the most of it. Possibly that merging cell. One of those freak mesoscale accidents I don't think I'd even see coming if it happened tomorrow right overhead.

 

[Kevin Walters]

Extreme instability makes up for a lot of things....there wasn't much for surface winds/convergence but enough veering with height to get the job done.

 

[TJKLECKNER]

The National Weather Service storm survey team determined that the tornado was an EF-1, with the worst damage occurring about eight miles north-northeast of Prescott, IA. The tornado traveled south before turning northeast:

http://www.weather.gov/media/dmx/StormSurveys/StormSurveyAug2_2015.pdf

 

[chrisbray]

Anyone take note of the Tornado that occurred just north of Chicago and out into Lake Michigan? There was a lone supercell that popped up very quickly just before the main squall line dropped south across the area, producing an EF-1 Tornado at night


http://www.weather.gov/lot/2August2015
Beautiful

 

[Joe Pudlik]

Witnessed the EF-1 tornado in Lake Co. IL (Round Lake/Grayslake/Gurnee) on Sunday. Pretty much all luck, being in the right place at the right time... Wasn't chasing, but happened to have just left Six Flags and saw it a short time after.

Chase log...

http://www.turbulentstorm.com/blog/august-2nd-2015-ne-illinois-chase