What am I looking at? Book End Vortex?

[Danny Neal]

* TORNADO WARNING FOR... CALHOUN COUNTY IN SOUTHWEST ILLINOIS... GREENE COUNTY IN SOUTHWEST ILLINOIS... JERSEY COUNTY IN SOUTHWEST ILLINOIS... SOUTHEASTERN PIKE COUNTY IN WEST CENTRAL ILLINOIS... EASTERN LINCOLN COUNTY IN EAST CENTRAL MISSOURI... EAST CENTRAL PIKE COUNTY IN NORTHEAST MISSOURI... * UNTIL 415 AM CDT * AT 332 AM CDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A SEVERE SQUALL LINE CAPABLE OF PRODUCING BRIEF RAIN-WRAPPED TORNADOES IN ADDITION TO WIDESPREAD STRAIGHT LINE WIND DAMAGE. THESE DANGEROUS STORMS WERE LOCATED ALONG A LINE EXTENDING FROM PLEASANT HILL TO ELSBERRY TO MOSCOW MILLS...AND MOVING NORTHEAST AT 60 MPH.

I think Greg was most likely referring to something along these lines. A broad multi-county warning without a real defined tornadic portion to the line. To me it is just a blanket TOR with the possibility of a tornado occurring somewhere(s) within that line. Although this particular area was rather small in coverage compared to the areas I saw a few hours later further east.

 

[Greg Blumberg]

Rob and Tim, thank you for correcting me.

I went back to the source where I had thought NWS warning decision makers used a TOR for a SVR. I was mistaken. The SVR warning I read asked people to treat the SVR as if it was a tornado warning, and I got it confused/backwards when I made my post. That's what I get for posting without drinking any coffee beforehand in the morning.

I do want to add that what Danny added was similar to the subjectiveness I mentioned regarding warnings. Certainly warning types have strict guidelines and are objective, but I would argue that to "stick to the script" attitude is detrimental to the public's interpretation of warning text. In adding this extra information in the warning, you cover all bases no matter which warning gets sent out. Customized call-to-action text can add other aspects of severe weather in combination to make the warnings seem connected and enhance the situational awareness of the general public.

Thoughts on TOR warning the line rather than specific locations...I actually agree with some WFO's decision to warn parts of the line and have the areas being large. Granted that some seemed to be excessive, I would argue that most were justified. You're given the fact that storm motions were incredibly fast, and you have a QLCS mode that can develop tornadoes in between 88D scans. Given the uncertainty of the situation when it comes from a warning perspective and understanding the limitations of radar, you are faced with deciding whether or not the risk of false alarm rates is justified in this situation. Given the wide coverage and severity of the event, I'd say that the warning process was not diminished in the eyes of the public by the false alarm rate.

I'd add that from looking at a warning/storm report composite map, it seems that there are several instances where smaller, more focused TOR warnings produced a higher false alarm rate than the larger ones. Granted that the larger your warning box, the larger chance you have for a positive hit when considering this, however in this instance, areas such as east of Fort Wayne had much multiple hits within the larger tornado warnings. (5 tornado reports in one of the larger warning boxes.) Given the uncertainty of the situation, larger warning boxes seemed more appropriate.

 

[Donovan Gruner]

Hey guys, a little late here, but here is a picture of a small bow echo along I-80 this year in Iowa. This storm was severe warned, and had a small tornado warning on the north edge, the dark area to the north.

As far as bookend vorticies, this is probably about all you're going to see I would think. As Bart said, as far as any supercellular characteristics go, they are going to be on the HP end of things. Hope this helps a bit.