JOPLIN, Mo. —
EYES OF THE SKY
The severe thunderstorm approaching Quapaw on Sunday caught the eye of Gunnar Wixon, chief of the Baxter Springs Fire Department.
“It was a very strange storm. The sun was still shining while a tornado was on the ground. I saw it about two miles out of town (Baxter Springs),’’ he said. “I radioed the fire station and told them to blow the sirens.’’
The blowing of the sirens gave Baxter Springs less than a minute to prepare for a direct hit. Others listening to Wixon’s radio frequency picked up on what was happening.
“After I notified Cherokee County, it spread onto everyone else,’’ he said.
When asked if he was compensating for a weakness in the radar, he said, “That’s absolutely true. But that was a very rare storm in that it happened so fast.’’
Allison, head of emergency management in Cherokee County, called the National Weather Service at Springfield, informing them that a tornado was on the ground in Cherokee County. Allison also called Stammer to alert Joplin and Jasper County. Those calls, in turn, led to the issuance of a tornado warning by Springfield and the sounding of the sirens in Joplin based on spotter confirmation of a tornado.
Said Stammer: “When that happens, the weather people call that ground truth.’’
Though it did not work that well because of the tornado’s location on Sunday, the new dual-polarization radar at Springfield has been effective at identifying other tornadoes.
“With dual-polarization radar, we can actually see debris from a tornado. This is what we call a tornado detection signature,’’ said Doug Cramer, a meteorologist with the National Weather Service at Springfield.
The upgrade is the most significant enhancement to the nation’s radar network since Doppler radar was first installed in the early 1990s.
The upgrade includes new software and a hardware attachment to the radar dish that sends and receives both horizontal and vertical pulses of energy, providing a more complete two-dimensional picture.
Doppler radar only sends out a horizontal pulse of energy that gives forecasters a one-dimensional picture of whatever is in the air. It can see precipitation, but can’t tell the difference between rain, snow and hail.
Dual-polarization radar helps forecasters clearly identify rain, hail, snow or ice pellets, and other flying objects, including tornado debris that has been lofted into the air.
Said Cramer: “It allows us to recognize what is rain, what is snow and what is sleet, but it also recognizes things that should not be up there, like sheet metal and roofing shingles that have been lodged upward by a tornado as debris.’’
The dual-polarization radar was installed at Springfield in early February 2012. It’s usefulness became apparent three weeks later on Feb. 29 when a tornado struck Branson.
“It was leap day of that year. We had a tornado outbreak and we were able to utilize it. It was the first time we actually saw tornadoes with the radar. It’s a big upgrade,’’ Cramer said.
With Doppler radar, a meteorologist could see rotation in a storm, but not actually see the tornado.
“Our goal is to issue the tornado warning before it touches down,” he said.
Another important benefit of dual-polarization radar is that it is especially helpful in the dark when ground spotters are unable to see the tornado.
“Most tornadoes hit between 2 and 10 p.m. In the daylight, spotters can see the tornado. At night, they cannot and it’s dangerous for them to be out there,’’ said Stammer. “At night, we rely totally on radar.’’