Most people avoid severe storms. Hurricane hunters fly precise routes into them.
“We’ll generally fly into the eye, then out and then circle back and do it again,” explains Major Devon Meistr, a pilot of one of the propeller driver C-130s that are part of the U.S. Air Force Reserves Hurricane Hunter Squadron. “We fly a triangle pattern back and forth through the storm. So what we are doing is collecting data around the perimeter of the storm.”
The planes are based in Biloxi, Mississippi. The data collected by the flight crew and weather crew on the plane is the only way to precisely locate the eye of the storm. It’s called fixing the eye.
“The only data they have at that point to forecast is satellite data, but that doesn’t tell you where the eye is, because the eye can be 30 miles or more. These storms can be hundreds of miles wide, so they can see what they think is the eye, but the eye will generally dissipate and redevelop; it will change sizes,” says Meistr. “So they need to pinpoint the exact center of the storm, because they put that information and that pressure into their models and that generates better models, better forecasts.”
The tracking missions typically last about 11 hours. The planes fly through the eyewall at the center of the storm, crisscrossing multiple times from 1,000 to 10,000 feet before returning to base.
“A lot of data is gathered from the aircraft itself because we have sensors on the airplane unlike other C-130s to help us gather weather data,” explains Lt. Col. Drew Clark, a navigator on the Hurricane Hunter planes.
He then holds up a tube with a small parachute attached at the top. “One of the main instruments we use to gather weather data is called a sonde, or a drop sonde, and this is similar to a device a meteorologist may send up in a balloon that climbs. But we drop it from the plane and it falls under a drogue sheet,” adds Clark. “It falls at 2,500 feet per minute, and as it falls, several times a second it’s sampling pressure, temperature, humidity and wind speed. So we get a nice vertical picture of the atmosphere from the latitude of the aircraft to the surface of the ocean, and that data is relayed via radio in this device back to the airplane.”
The data is reviewed for accuracy and then relayed from the plane to the National Hurricane Center to be used in creating the forecast track for the storm. Roughly 15 dropsondes are sent out during a flight, usually in the eyewall, inbound into the center, in the center, and then another one in the eyewall outbound from the storm.
Flight crews may also send out a dropsonde if something unusual is spotted, such as a heavy rain band or maximum winds.
All of that information is vital to weather forecasters because of the way a hurricane functions.
Hurricanes form when vast stretches of ocean are warmed to 82 degrees. Warm, moist air rises over those hot spots creating thunderstorms. Upper level and surface winds come together to form circular clouds and a tropical depression. That’s the signature spinning cloud pattern.
On the other hand, high altitude winds can tear a hurricane apart. But if there are no winds, hurricanes can reach up to nine miles high.
That central area of the spinning clouds becomes the eye of the storm. It has the lowest pressure and it’s calm. The surrounding eye wall has the highest winds.
As the air from the sea surface is pulled in towards the eye, it rises and cools, releasing moisture and heat. The heat causes the air to rise further. That continues building and driving the hurricane. It’s also why so much rain comes with a tropical storm.
The storm is pushed by trade winds. However, once a hurricane arrives over cold water or land, the energy supply is cut and the storm breaks apart.
“It’s all further proof that a hurricane is not just a point on a map and the deadly hazards can occur far from the center outside of the cone,” says Rick Knabb, Ph.D., who's also the director of the National Hurricane Center. “We think of hurricanes as these big wind machines and the winds can be deadly, but nine out of 10 people who die in land falling tropical systems in the United States die due to water.”
Thus if forecasters can see what is happening in the storm, as well as the surrounding ocean and atmosphere, they can better predict what the storm will do next. NOAA officials say the data can increase the accuracy of forecasts by 30 percent.
And to find out what is happening outside the storm, NOAA uses a specially modified Gulfstream jet. Durham native Doug Macintyre is one of the pilots.
“The radar at the front of the jet gives us a picture of rain bands and weather ahead,” explains Macintyre as he walks around the jet. “This tail Doppler radar gives us a cross section through the entire storm environment; it’s akin to looking at a cake and taking a nice slice through it. So we can look at all the layers of the storm from 45,000 feet to the surface of the ocean."
Like the crews in the C-130s, the gulfstream jet is also equipped to send out dropsondes to study the storm. The information received is relayed from the jet to the National Hurricane Center.
Macintyre says the speed and agility of the jet allows meteorologists to not only study the storm itself but also the air and weather systems around the storm, which greatly affects where the storm is tracking.
“My best example is Hurricane Matthew, which was a long but very valuable flight for gathering data,” Macintyre adds, taking a deep breath before describing the trip. “We took off from St. Croix, flew around the Atlantic Ocean to sample the air mass in the ocean, circumnavigated the storm to get all of the reading around the storm environment, then transited to the Gulf of Mexico and sampled the air mass there.”
The journey provided the Hurricane Center with a complete model of the Atlantic, the storm and the gulf, which provided a better reading of how the storm would likely have moved up the East Coast.
Macintyre says he remembers growing up in Durham and hearing the hurricane warnings for the coast. He also remembers the damage the storms can do far inland.
“Even today when a hurricane threatens the coast, I’m on the phone calling my parents, my brothers and sisters and saying if there is an evacuation you need to heed those warnings,” Macintyre says. “That’s our mission: finding out where the storm is going and keeping people safe.”
Jason Franklin, the Meteorologist-In-Charge at the National Weather Service office in Raleigh, reiterates the importance of acting on their warnings.
“And that’s where we come in from a communications standpoint, because we need to tell people about the threat and people need to take it seriously,” says Franklin. “People may not like to hear it, and they may think the threat is overstated, but we’re not here to win a popularity contest. We’re here to protect lives and property, so when we say it’s going to be bad people really need to take heed.”
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