KANSAS CITY, Mo. — Located in the rolling hills of eastern Kansas - just west of Kansas City - is Tonganoxie.
It's a small city but some say it has a big impact on the city's weather - The Tonganoxie Split.
"A former weatherman, I think on one of the channels, coined that and it had something to do with the weather patterns, how they approach here and then veer off in another direction," Mike Emery told me.
The people I spoke to in Tonganoxie - including Mike - seemed split on the idea
"Do you think it's real? I highly doubt it," Emery said.
Ron Zink was also familiar with the term.
"I couldn’t say yes or no, but it seems like it happens an awful lot," Zink said
Stories in local publications over the last few years have dismissed the idea, with one saying there is "no science to back it up." I've found that's not an unpopular opinion among local experts.
"I've been to a lot of weather seminars and everything, and they all say the Tonganoxie Split doesn't exist," storm chaster Mark Randel told me.
For a look at what the numbers say, I turned to David Mechem, an atmospheric sciences professor at the University of Kansas.
"If you were to calculate statistics from all of the storms over many many years, I don't believe it would show a meaningful splitting effect tied to Tonganoxie," Mechem said.
Rivers and mountains don't stop storms or tornadoes, so why would anyone think a small town of 6,000 could stop a squall line approaching Kansas City?
I've been following this issue for a while, during which I spoke with Jiwen Fan. She's also an atmospheric scientist. She says something like the Tonganoxie Split is possible.
"When you break that balance, that storm will be split, and you will not have that organized over the city," Fan told me.
Research backs this up, including in a well-known study about splitting storms in Indianapolis, which has a very similar-sized urban core. A story from St. Louis in the 1970s also showed a splitting effect.
My research led me to Bob Bornstein. He's a professor emeritus at San Jose State University. He's been studying the effect for decades.
”It really is the physical presence of the buildings that causes a barrier effect that causes the flow to bifurcate around the city," Bornstein told me. "As the storms approach they get caught up in that bifurcated flow and they also split because of internal mechanisms inside the thunderstorm."
Squall lines stay together by balancing inflowing warm air and the backside cool temperatures. As the line approaches Kansas City, that warm inflow gets disrupted, creating an imbalance or lack of lift to sustain the storm. That disruption seems to begin near Tonganoxie.
“When you have a strong urban heat island, the city will actually initiate a thunderstorm right over the city and give you a maximum right over the city," Bornstein says. "When you have a cloudy day and a weak urban heat island, the storm bifurcates and goes around the city.”
If this phenomenon can happen in cities all over the country, and the world, why not also here in Kansas City?
“I think so, Kansas City is about the same in areal extent and population," Bornstein says.
We might have even had a split just a few weeks ago in March.
The split doesn't happen with every storm, and until we study these storms in Kansas City, we can't say with certainty the Tonganoxie Split is real, but at this point, we shouldn't deny its plausibility either.
Maybe that former weatherman - Dan Henry - was on to something.
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