What made the difference for Butler County on Friday night when a severe storm system left a 200-mile path of destruction across the Midwest?
That system found highly unstable conditions in Arkansas before it could reach this section of the Missouri-Arkansas border, along with strong wind shear that then forced it east, according to the National Weather Service.
Conditions — unseasonably warm temperatures and high humidity — were the same in Butler County and in the areas where the tornado system first touched down, explained Michael York, NWS meteorologist.
“Really, it wasn’t that much different at the ground level,” said York. “You really couldn’t feel much difference between West Kentucky and Poplar Bluff.”
But sometimes it’s a subtle difference that can make a big difference in severe weather, he said.
“The winds were out of the south and the storms that were out of Arkansas intercepted all of that warm, humid air that would have reached Poplar Bluff otherwise,” York said. “Because the storms formed to your south, they kind of prevented storms from forming further north, because they were intercepting that unstable air ...
“The more wind you have aloft, the more wind shear there is, (and) in this case we had winds near 100 miles per hour at 20,000 feet. That’s a tremendous amount of wind, especially if there’s instability. Rarely is there that much instability if you have that much wind.”
If there’s enough of a front, it will tend to cut off the moisture heading into an area, he said.
“In this case, they did that for your area, but not for Western Kentucky,” York continued.
The NWS was still evaluating the path of the storms as of Monday, but have said at a minimum EF-3 damage was done in Mayfield, Kentucky, as well as the Dawson Springs area.
EF-3 tornadoes can see wind speeds of between 136-165 mph.
Officials were also examining damage in Defiance, Missouri, which is also believed to have been an EF-3 tornado.
The Poplar Bluff Severe Weather Response Team was prepared Friday, in the event that the damaging fronts did reach the area.
Local first responders met Friday morning to review the potential for severe weather and eight to nine volunteer storm spotters were deployed in the evening, said Craig Meador, of the PBSWRT.
“It was one of the strangest weather set ups that we’ve seen in a long time,” said Meador. “(Spotters) were out at the same time that the big thing was rolling through Kentucky.”
All of the spotters are elite spotter certified by the NWS and trained to recognize the differences between potential funnel clouds and other weather events.
The closest radar to Poplar Bluff is in Paducah, Kentucky, but by the time it “sees” Poplar Bluff, it is seeing conditions at 5,000-8,000 feet, Meador said.
Storm spotters are needed to provide early warnings because the storms are forming at 500 feet, he said.
Poplar Bluff saw a hard rain and wind gusts of up to 52 miles per hour were reported at the airport Friday evening, Meador said.
No damage was reported locally, officials have said.