7/7/10 DISC: WI

[Andy Wehrle]

In northeast Columbia County,

STORM CHASER REPORTED A MULTIPLE VORTEX TORNADO WITH DAMAGE PATH ESTIMATED 200 TO 300 YARDS WIDE. TORNADO DISSIPATED INTO A ROTATING WALL CLOUD BY 655 PM.

I watched this on radar, stunned to see that small cell take on a hook shape and a very prominent, tight couplet on a no-risk (< 2% TORPROB) day.

Was that "chaser" anybody on here? What clued you in to even take a glance at the mesoanalysis today, let alone go out there?

 

[Scott Weberpal]

There was nothing synoptically or even on the mesoscale that would have indicated tornadoes were possible. Lapse rates were junk and low-level winds very week. It likely occurred along a boundary interaction from previous storms.

Low-level turning wasn't along the lake breeze with southeast winds near the lake, and I did notice the nearest observation to Cambria had a 10kt southeast wind, again, likely the result of an outflow boundary from the earlier convection which had moved toward Green Bay.

 

[Doug Raflik]

In northeast Columbia County,

STORM CHASER REPORTED A MULTIPLE VORTEX TORNADO WITH DAMAGE PATH ESTIMATED 200 TO 300 YARDS WIDE. TORNADO DISSIPATED INTO A ROTATING WALL CLOUD BY 655 PM.

Was that "chaser" anybody on here? What clued you in to even take a glance at the mesoanalysis today, let alone go out there?

I know a guy in that area that "chases" storms in that county. My first guess was him when I saw the report.

Doug Raflik

 

[Rich Dorfman]

Not me but when in doubt, head for Columbia...

 

[Paul Knightley]

Could this be related? http://www.youtube.com/watch?v=JpF11CPQ_YY

 

[Ben Kossow]

Here's another video from local media.

 

[Bob Hartig]

It is just plain weird that this thread even exists. I was watching the radar yesterday when the tor warning in Wisconsin popped up, and my first response was, What the...? My second was to shrug it off. Doppler warned, it ain't nuthin'. Just goes to show how Mother Nature can mess with your head.

Synoptically there was just nothing going on yesterday that even hinted at tornadoes. Wisconsin does have the advantage of an easterly lake breeze, but, as Scott has suggested, yesterday's storm was well inland. It's the tornado that had no right to be. Nevertheless, there's that red dot in the storm reports, plus some videos that show more than just a minor spinup at work.

 

[Brad Williams]

Same thing here in eastern Nebraska and Western Iowa. The local news had photos of a funnel in Western Douglas County (Omaha) from one small cell. Then the sirens in Pottawattamie County Iowa were sounded after multiple reports of funnel clouds from another small cell.

 

[Ben Kossow]

I was out on Nagawicka Lake in Waukesha County when the storms first started yesterday afternoon and saw a some rotation in one storm. I had about the same reaction. Wasn't enough to warrant a report, but I did keep an eye on it for about 15-20 minutes until it sputtered out.

But, as Rich pointed out, Columbia County and central Wisconsin spins these guys up every now and then.

 

[Tim Marquis]

Wisconsin is well known for these landspout events. The 18z mesoanalysis had a highlighted area of non-supercell tornado parameter. This parameter has a high reliance on surface wind convergence and depicts false positives (such as today's 18z data depicting a risk in dry areas.) However, it was highly useful in yesterday's event because it accurately picked up on the lingering boundaries and highlighted the Columbia County area and parts of Northeast wisconsin. The green bay office got multiple reports of funnel clouds when these multicells initially formed and had highlighted in their HWO the threat for funnel clouds. Overall, not surprised by the event. I got to the cell at around 00z when it was approaching the Waupun, Wisconsin area, right when the tor warning was dropped and for good reason. Rotation had already started to weaken. At that point, a wall cloud was still rotating slightly but was highly disorganized. It literally was about 15 miles away from producing a tornado over a wind farm though.