New weather project could help track tornadoes more closely

The 1996 movie "Twister" showed storm chasers travelling across Oklahoma and Kansas toting Dorothy, a mobile device that launches hundreds of flying sensors into a tornado.

In the film, Dorothy works by collecting data from the sensors, but in real life that would be nearly impossible, said Don Burgess, retired National Severe Storms Lab meteorologist.

Burgess said Dorothy is just a movie prop. It was based on a real piece of technology from the early '80s that did not fling hundreds of sensors into the air. Instead of Dorothy, it was called the Totable Tornado Observatory - TOTO for short.

TOTO weighs a few hundred pounds and holds basic atmospheric sensors that measure temperature, wind speed, pressure, dew point and other atmospheric characteristics, Burgess said. Burgess said the National Severe Storm Lab used TOTO for four or five years, but they did not have much success with it. It was big, bulky and difficult to put in the path of a tornado.

"There was just one TOTO; it was heavy and took a while to deploy," Burgess said. "We got close a number of times but had a problem getting a tornado to go right over it "

The technology in TOTO was high-tech for its time, but forecasters needed better technology to learn more about tornadoes, Burgess said.

In the mid '90s, a new design, VORTEX 1, incorporated new technologies developed after TOTO, NSSL Deputy Director Kevin Kelleher said.

Burgess said the VORTEX 1 machines that replaced TOTO are called Turtles. These devices are smaller and easier to deploy, and there are numerous units that can be placed in a grid.

Kelleher and Burgess described these devices as large, upside-down metal bowls that are loaded with atmospheric sensors. "You can set those out real quick so you don't have to worry as much about the safety factor," Burgess said.

Kelleher said forecasters learned a lot from VORTEX 1, but it there was still a lot to discover.

"VORTEX 1 was initially designed to find out what causes rotation," Kelleher said. "We wanted to forecast how [tornadoes] occur and how they dissipate, and what we learned is there is a lot we don't know."

New Technology

Large-scale tests like VORTEX 1 happen fairly rarely, NSSL Research Meteorologist Lou Wicker said. "VORTEX 1 made a significant difference," Wicker said. "But now we have a lot more technology to make real-time predictions, which can increase warning times."

The NSSL and National Oceanic and Atmospheric Administration are working with the National Science Foundation to develop VORTEX 2, Kelleher said.

VORTEX 2 is a bigger and better version of the original VORTEX project, he said. The NSSL will prepare this spring for the test, which will be conducted in the springs of 2009 and 2010, Kelleher said.

"It is basically VORTEX 1 on steroids," Wicker said.

VORTEX 2 was developed to give researchers a better understanding of tornadoes and increase the warning time for those in the path of tornadoes, Kelleher said. VORTEX 2 should help forecasters complete the picture of how and why tornadoes occur, he said.

"The goal is to use the best observations we have now and all of the information we gathered in VORTEX 1, and take that to make models," Kelleher said. "The end game is to help forecasters predict what is going on more accurately."

In VORTEX 2, the NSSL and partners will track the storm from all sides at three different levels and will use most of today's available forecasting technology.

Tracking a storm

The first level of observation includes Turtles, Stick-nets – another type of sensor – and Mobile Mesonets, vehicles with sensors attached to their roofs. This level of observation records basic atmospheric functions.

The second level of observation is conducted by trucks called Shared Mobile Atmospheric Research and Teaching Radars, known as SMART-Radars.

In 1997, OU, the NSSL and other partners developed these trucks, which are 34 feet long and have a 5 cm Doppler radar dish in the back, said Mike Biggerstaff, associate professor of meteorology and director of the SMART-Radar program. The 5 cm dish is less powerful than the larger stationary 10 cm Doppler radars, but its mobility allows it to move much closer to a storm and observe a clearer picture, he said.

The SMART-Radars are able to use radar signals to penetrate the storm, which bounce back and produce an image of what the storm looks like, Biggerstaff said.

"We can see the entire storm scale, the effect of the updrafts and the downdrafts on the development of circulation," he said.

On the third level of observation, behind the SMART-Radars, are the larger stationary 10 cm Doppler radar dishes. These radars provide a much farther-reaching radar sweep, Biggerstaff said. The more powerful beam provides a picture of the storm and areas surrounding it. Like the smaller radars, these take data and plug them into a computer algorithm, which creates a map of the storm, he said.

In VORTEX 2, the NSSL will also incorporate the new phased array radar, which was developed by the military. Phased array radar uses multiple beams and frequencies to reduce scanning time and can give forecasters minute by minute updates, Kelleher said.

Biggerstaff said there has never been a weather experiment as extensive as this one. And what makes VORTEX 2 so unique is the combination of all the technologies to create a data set that can be used to forecast future storms.

"I don't even think we have found all the ways that tornadoes form," Biggerstaff said. "We need to be able to observe all the scales of motion, and VORTEX 2 is designed to allow that to happen.”