In the early hours of August 19, 2019, a tropical wave appeared off the west coast of Africa. A few days later, it began showing signs of organization and cyclonic movement inside a small low-pressure area. By August 24, the system had grown large enough to qualify as an official tropical depression centered about 700 nm southeast of Barbados. That depression, now known as tropical storm Dorian, made landfall over Barbados with sustained winds of 45 knots. Dorian continued to intensify as it approached St. Croix later that day with increased winds of 65 knots, and by August 30, Dorian was labeled a Category 3 hurricane with winds of 115 knots.
By the time Dorian reached the Bahamas’ Elbow Cay in Great Abaco, the storm had grown to a Category 5 with sustained winds in excess of 160 knots. Dorian’s devastation eventually matched its fury, nearly obliterating Great Abaco with $3.4 billion in damage. A National Oceanic and Atmospheric Administration report said water levels reached more than 20 feet above ground level in some areas. Dorian slowed to a crawl over the northwestern Bahamas, dumping nearly 23 inches of rain at Hope Town in addition to claiming some 200 lives in the area.
Though Dorian weakened as it approached the US mainland, the storm re-intensified to Category 3 status as it headed north, skimming past Georgia and South Carolina, its eye passing near the Outer Banks of North Carolina. Dorian dumped nearly 16 inches of rain at Pawleys Island, South Carolina, before crossing Cape Hatteras. After clearing the Outer Banks, Dorian accelerated northeastward and became a strong post-tropical cyclone on September 7 before it reached Nova Scotia, Canada, and eventually spun out into the North Atlantic.
Hurricane Dorian spawned 21 tornadoes between September 4 and 6, two of which reached EF2 intensity. While no deaths were reported in the US, NOAA’s National Center for Environmental Information put damage in the United States alone at $1.6 billion.
As the Season Begins
The US hurricane season runs for 153 days each year between June 1 and November 30. Thanks to significantly improved hurricane forecasting, aircraft operators today often receive enough advanced warning to button down in place or move their aircraft to safer locations. The trick for the experts is how to continue improving the forecasting of these often-temperamental storms in time to be useful to people in their paths.
The job of gathering data, creating forecasts and accurate storm modeling—essentially acting as first responders to hurricanes—falls to groups such as NOAA’s National Hurricane Center in Miami and its operational arm of hurricane hunters based in Lakeland, Florida, the Aircraft Operations Center.
The NHC’s mission is simple: “To save lives, mitigate property loss and improve economic efficiency by issuing the best watches, warnings, forecasts, and analyses of hazardous tropical weather and the understanding of these hazards.”
The AOC’s team of about 100 men and women are responsible for capturing the most up-to-the-minute storm data, such as temperature, winds and humidity, by flying directly into the teeth of weather most other pilots are happy to avoid. AOC aircraft include a pair of Lockheed WP-3D turboprops—originally known as Electras in civilian paint schemes—and a single Gulfstream IV biz jet. Their efforts are supported by a pair of NASA/NOAA GOES satellites hanging in stationary orbits more than 22,000 miles above the planet.
Tropical Cyclones Dissected
Hurricanes, technically known as tropical cyclones, are giant engines of nature fueled by warm, moist air—between 80 and 85 degrees Fahrenheit—that form in the tepid ocean waters near the equator. Colorado State University meteorologist Phil Klotzbach, in a USA Today story, labeled hurricanes as “the atmosphere’s attempt to move heat from the warm equatorial regions toward the cold polar regions.” In the western Pacific and Indian Ocean, these same storms are called typhoons.
NASA’s website explains how hurricanes evolve: “As warm, moist ocean air rises, it causes an area of lower air pressure beneath, while higher-pressure air from surrounding areas pushes into these low-pressure regions, warming and adding moisture as it all moves. The surrounding warm air swirls eventually, cooling and forming clouds. The entire system of clouds and wind spins and grows, fed by the ocean’s heat and water evaporating from the surface.” North of the equator, tropical cyclones spin counterclockwise, while the direction is just opposite down south. Hurricanes also include clusters of intense thunderstorms concentrated in a relatively small area.
The Saffir-Simpson scale categorizes hurricanes according to their sustained winds. A Category 1 storm brings winds of at least 64 knots, a Category 3 has winds in excess of 96 knots, and a Category 5 includes winds of more than 137 knots, or 157 mph. Categories 3 through 5 are considered major storms. In a Category 5 hurricane, a high percentage of framed homes will be destroyed, power outages can last for weeks or possibly months, and most areas will remain completely uninhabitable for weeks or months. And tropical cyclones are often unpredictable. Hurricane Maria destroyed much of Dominica in 2017, growing to a Category 5 by the time it made landfall, causing some $1.31 billion in damage, while Martinique just 50 miles to the south received only minor damage.The Hunters and Their Weapons
Understandably, people are often skeptical of the accuracy of weather forecasters. Hurricane forecasters are no exception. Jonathan Zawislak, a scientist at the Cooperative Institute for Marine and Atmospheric Studies at the University of Miami and NOAA’s Atlantic Oceanographic and Meteorological Laboratory, says: “Certainly within the last couple of decades, we’ve seen improvements in general and track forecasting, although predicting hurricane strength is hard. Hurricane Michael in 2018 rapidly increased in intensity just before it made landfall.” In the end, he says: “Realize these are all just forecasts. No matter what, people still need to prepare because it only takes one storm like a hurricane Michael or Andrew, even during a slow season, to create chaos.” Hurricane Michael, in fact, became the strongest Category 5 storm ever to reach the US, in a season predicted to be nothing more than average.
As a research scientist, Zawislak often rides along on NOAA aircraft headed into the teeth of hurricanes to gather the most up-to-date data necessary to create forecasts and fuel the research efforts needed to better predict future storms’ intensities and paths. “We at the University of Miami support research from NOAA, but also with NASA, NCAR and other universities, so 10 heads working on a problem are better than one.” He adds: “It takes a broad range of backgrounds to improve our hurricane numerical models, tools that are really just differential equations. We need people with strong computer science skills, as well as physicists and meteorologists.”
A typical mission crew aboard a WP-3D includes a lead project scientist, who communicates the flight pattern needed to ensure the mission’s objectives are met. There is also a science crew, the aircraft flight crew, and a flight director who’s responsible for the overall safety of the flight. “The flight director, a meteorologist, acts as the liaison between the flight crew and the mission people,” Zawislak says. Flight dispatchers back in Florida handle the continual cycling of the flight crews.
The WP-3D Orions carry between 16 and 22 people, with typical missions carrying 16 to 18. NOAA’s flight crew consists of three pilots, two flight engineers, a flight director, navigator, data-systems technician, dropwindsonde operator/technician, system engineer and avionics technician. The remaining seats are used by research scientists, with typical hunting trips running about eight hours. The Gulfstream carries eight to 10 people.
The Orions are outfitted with sophisticated sensors and radars such as lower-fuselage and tail Doppler radar systems. Mounted to the belly of the aircraft, the LF radar scans the storm horizontally while the TDR scans vertically to create an MRI-like look at the storm. That information is pushed to the NHC within an hour of collection. That same information is shared with NOAA’s Environmental Modeling Center for inclusion in the high-resolution hurricane forecast models being created regularly. In earlier times, when weather satellites were still new, the only option to gather data came by flying as close to a storm as possible and simply looking out the windows.
Jack Parrish is a 41-year NOAA veteran, with most of that time spent as a hurricane mission flight director sitting just behind the aircraft commander. A Florida native, Parrish grew up around hurricanes. Prior to earning a meteorology degree, Parrish served in the US Coast Guard as a radar technician. “Just after I finished college,” he says, “the Hurricane Research Division in Miami was looking for a meteorologist who also understood radar. My only question to them was, ‘Will I get to fly in hurricanes?’ They said, ‘Yes,’ and I said, ‘Hired.’”
Twenty-eight years later, he still remembers well a close brush in 1992 with Hurricane Andrew, a Category 5 storm with wind gusts of nearly 170 mph that flattened significant portions of South Florida and south-central Louisiana. While Parrish’s family escaped unharmed, Andrew claimed his home. He remembers being on the Orion back then during a moment that confirms even today why a human element is so important to hurricane forecasting. “Andrew was just a disorganized mess northwest of Puerto Rico,” he says. “Dropwindsonde data started telling our scientist on board, James Franklin, however, that conditions might be ideal for Andrew to rapidly intensify. It sure hadn’t done anything up to that point. Then James got quiet for a second before he said, ‘Uh-oh.’” Parrish and his team suddenly realized Andrew, still two and a half days east of the US mainland, was about to make a hard-left turn. “We dragged out the paper charts we used at the time and drew some lines. They went right through south Miami. We never knew Andrew was going to gin up that way, but we became the first ones to know about it.”
Parrish says a typical mission’s preflight briefing begins with a discussion of information from the previous flight, except when this will be the first flight into a storm. “What I’ve learned,” he says, “is that by the time we reach the actual storm, sometimes three or four hours after the briefing, our info can be pretty stale. I’m comfortable now realizing that an area we thought might be a milk run to fly near may have become a ring of fire—information that must be passed on to the rest of the crew. My most important tools are my eyeballs looking out the windows and interpreting the onboard radar, but I’ve also learned to be ready for radar shadows and attenuation that might be hiding other hazards. It’s very much a real-time show each time we make a pass through a storm.” The hurricane hunters don’t always fly into growing storms. Missions often include flights into dying storms that might get mixed up with a cold front as they head up the East Coast of the US and could potentially beat up the people in regions up to Nova Scotia.
Thinking back 30 years or so, Parrish speaks to how hurricane forecasting has changed the lives of people in the path of a big storm. “Consider Dorian. We flew into that storm every day, and it just got stronger and stronger, well into Category 5 territory. Dorian leveled Grand Bahama about 70 miles from West Palm Beach, yet we were quite secure telling people on the east coast of Florida no more than to watch out for heavy surf. With the kind of information and forecasting we had 30 years ago, we’d have been evacuating people to Chicago.”
Despite the human connection, Zawislak explains NOAA’s growing use of expendable unmanned aerial systems, especially to cover regions deemed too dangerous for manned aircraft. Zawislak says the drones are used primarily near the incredibly turbulent boundary layer—typically within 1,000 feet of the water’s surface—to measure the sea spray that can fly a few thousand feet back up from the surface. “Working in that area tells us how the ocean releases its energy into the atmosphere,” he says. “The data we can get from a one-hour drone flight here is invaluable. Because this area is subject to incredible turbulence, we’ll never fly the aircraft below 5,000 feet in a small storm or 8,000 feet in a major one.” The UAS released from the WP-3D has a 3-foot wingspan and weighs between 10 and 11 pounds. Despite their size, Zawislak says, “They handle turbulence pretty well.”
Each April, Colorado State University’s well-known Department of Atmospheric Science releases its annual hurricane forecast. NOAA’s forecast appears a month or so later, just before the hurricane season begins, with updates once the season gets underway. For 2020, the university believes we will see “an above-average probability for major hurricanes making landfall along the continental United States coastline and in the Caribbean.” An extremely important side note warns: “As is the case with all hurricane seasons, coastal residents are reminded that it only takes one hurricane making landfall to make it an active season for those people. They should prepare the same for every season, regardless of how much activity is predicted.” Penn State’s Earth System Science Center predicts we’ll see 20 named storms, potentially making 2020 the most active hurricane season since 2010 and 2011.
While Parrish and Zawislak find hurricane hunting exciting, their job gathering research and forecast data is also incredibly dangerous. Parrish amusingly says: “We often place aircraft too close to severe weather to be sensible. But then we must also get everyone back safely.” Before Parrish and I rang off during our interview, I asked if he’d ever seen a hurricane he didn’t want to fly into. Without a moment’s hesitation, he replied, “Pretty much all of them.”
Follow the Hurricane Hunters: Important Updates for Pilots
NOAA Aircraft Operations Center is on Instagram: @FlyNOAA
NOAA National Hurricane Center is on Twitter and Facebook: @NHC_Atlantic
The Atlantic Oceanographic and Meteorological Laboratory Hurricane Research Division posts during and after hurricane missions on Twitter and Facebook: @HRD_AOML_NOAA
This story appeared in the June/July 2020 issue of Flying Magazine