HUNTSVILLE, Ala. – No doubt you’ve heard about Hurricane Hunters flying into the eye of hurricanes.
But did you know that the same aircraft –a WP-3D Orion — is used to chase tornadoes?
“We can go to the weather. And we can get there relatively quickly in our P-3, and beyond that, we can stay in and round the weather for a long time,” said Michael Holmes, Flight Director and meteorologist for NOAA’s Aircraft Operations Center Hurricane Hunters.
It may seem counterintuitive, but it’s a strategy that severe weather researchers have used since the early 90s.
“Dave Jorgensen was one of the first pioneers to use the new NOAA Hurricane Hunter Aircraft with their radars in the mid-1970s,” explained Conrad Ziegler, a research meteorologist at the National Severe Storms Laboratory (NSSL) in Norman, Oklahoma.
“[He figured] out how you would study a supercell thunderstorm by flying “legs” along one side and then going up the other side and then combining the measurements from the onboard radar, the beams, to determine the wind fields. Those were the pioneering concepts that were laid out in the early 70s.”
“But by the early 90s, we refined those concepts of how to obtain wind fields from these two beams — one pointing aft and one pointing forward — relative to the direction the aircraft is flying, and so we could fly single legs, combine those two wind measurements and get the 3-dimensional airflow within the storms,” Ziegler continued.
“We applied what we learned about using the P-3 in a tornado experiment called VORTEX-94 and VORTEX-95. It was really the first of the VORTEX experiments, and we flew the P-3 in both of those years.”
And the advantage of chasing tornadoes in the air is invaluable.
“We go 240 miles an hour, so we can get pretty far in no time,” explained Dave Jorgensen, Research Scientist at the Warnings Division of the National Severe Storms Laboratory (NSSL).
Jorgensen isn’t kidding.
On this particular research mission, the P-3 left Huntsville shortly before 1 p.m. Central Time. Within one hour, the aircraft was already two states away, near Hot Springs, Arkansas. In comparison, if a research meteorologist left Huntsville via truck, they would be in Rogersville — two counties away — within the same amount of time.
“On the ground, you are committed to a location and you just hope the storms will come close to you. And so what we’re measuring with the radars [on the airplane] is basically very similar things [compared to radars on the ground],” Jorgensen states.
“By using the aircraft, we can get close and we can fly patterns that will enable us to do these analysis and get the wind flow very accurately. And ground based radars can do the same thing, but you gotta be lucky and have the storms go to you,” Jorgensen elaborated.
And unlike ground-based single truck radars, the P-3 is equipped with three separate radar systems, all used to research storms from about a mile and a half above the ground.
“We have a lower fuselage radar, [it] can look 360 degrees around us and it makes a sweep just under every minute,” Holmes explained.
“We use that to guide us in and around both near and far features.”
“We also have a nose radar that both the flight crew have the visibility on as well as the flight directors, and that’s kind of what we use to look just directly out in front of us and do our tactical maneuvering,” Holmes continued.
“Lastly, on the rear of the aircraft, we have a tail doppler radar. If we’re flying north, it scans east and west along our flights so it generates this volume of reflectivity, or if anything were around this volume scan of everything around us on our side.”
“A really unique feature of this tail doppler radar is it gives you the common reflectivity values, but it also gives us the winds, the horizontal wind speed and direction and the vertical winds. It’s a critical value.”
As flight director, Holmes’ main responsibility is to ensure the safety of all crew onboard the aircraft during the research mission.
“We will not fly into a tornado, or even a severe weather convective line,” he said reassuringly.
“The dynamics between flying into a hurricane eyewall and flying a Midwestern or Southeastern severe weather event are very different. Vertical velocities are extraordinary and there’s hail,” Holmes cautioned.
“Hail would destroy the airplane, and so that’s why we’ve identified a safe standoff distance out in front of the line or convective cell. And we’ll just parallel it.”
“Our radars would be able to peer into it so we would get all that data but we don’t have to go into it,” Holmes concluded.
For each target thunderstorm, the goal is to fly no less than five to ten miles away from the storms in order to obtain a 3-dimensional view of the environment. This may provide clues to what causes some storms to become severe — and to potentially produce tornadoes.
The result: improved severe weather forecasts for all of us on the ground.