Another Quizzical Tornado Warning

While this tornado caused damage in central Illinois early this afternoon, hopefully no one has been injured. But, I simply don't understand what transpired and I'm hoping some of my helpful readers can fill me in.

The possibility that tornadoes could occur in central Illinois was forecasted by the NWS Storm Prediction Center at ~11:45am (brown, below).

Given the fact that a derecho was approaching the area at 70 mph, it was essential Lincoln - Central Illinois radar be switched to the 80-second "tornado" mode.

At 12:06pm (velocity time, upper right of the frame), there was very weak rotation just west of Berlin, IL. 

Had it been me, I would not have issued a tornado warning at this time. The rotation was too weak. I have highlighted the town of Loami, which becomes important in the next frame. 

Because of the 3.5 minute interval between frames, the next data indicates a full-fledged tornado is doing damage! Any hope of advance warning was lost because the radar was operating at ~210 second interval intervals rather than 80.

At upper right, the rotation is robust. At lower left, the spectrum width data (gray pixel) likely shows the center of the funnel. At lower right, the lowered "correlation coefficient" depicts lofted debris. 

The National Weather Service (NWS) in Lincoln issued a tornado warning at 12:12pm. 

This warning has negative "lead-time" (-3 minutes; the tornado was on the ground at least three minutes before a warning was issued), it says the tornado is moving "east." If it was 9 mi. west of Springfield, it should be moving toward that city.

It also says "radar indicated rotation" when it should say "radar confirmed," which gives it extra credibility, because of the lofted debris. Finally, it says the tornado is near Loami "moving east at 55 mph." The problem are it is not over Laomi and an east movement would take it along I-72. All of this is wrong. 

At 12:12pm, the tornado is clearly moving southeast not east. 

The rotation (upper right) continues. The location of the funnel (spectrum width, lower left) and the greater amount of lofted debris (lower right) are in precisely the same location. The tornado continued to move along the ground. 

I had been tweeting about a potential tornado farther north didn't begin noticing this storm until the tornado warning came out about about 12:14pm. 

But, when I took a look at several frames, it was obvious the "east" movement was wrong. The tornado was exiting the tornado warning (red) polygon. Rather than explain, I thought it was essential to get something about as quickly as I possibly could. Note the storm was nearly over Chatham and well south of Springfield.

The NWS reissued the tornado warning and oriented it toward the southeast. 

But, the text of the tornado warning said is was moving "east at 75 mph"!

So, to someone listening to the radio or not having access to video, they would have been misled as to the area threatened. This is part of what went wrong a dozen years ago in Joplin!

Did the Tornado Cause Damage?

Unfortunately, the answer is "yes."

Part of the roof lifted off

Power Outage Map

The red county in the center represents half of the customers out of power. 

These reports are highly preliminary.

The point is that it wouldn't have mattered if it was a weak tornado (which is likely the case) or a strong tornado -- the radar can't see a tornado if it is not looking. With tornado mode, it would have been looking nearly three times as quickly.

But, there are other troubling aspects to this incident. 

• Why the obviously wrong direction of movement? 
• Why wasn't the wrong direction corrected?
• Why use a tiny town as a geographic reference that wasn't nearby or in the path?
• Why not say, "radar confirmed" -- giving the warning added credibility -- as it was?

The recent fatal tornadoes are more important than this incident. But, this clearly demonstrates that running the radar at the wrong data interval and other issues are not confined to one state or region.