Hurricane hunter flight patterns may look like boxes and stars, but they serve a specialized purpose for each storm.
The alpha pattern is popular among storm chasers. Photo: CNN
Hurricane hunters don’t fly far away from a storm like commercial aircraft do. Instead, they head straight into it, though not randomly, according to CNN . There are two independent groups of hurricane hunters: the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Air Force Reserve (USAF). Both organizations fly missions into tropical storms to record invaluable data for forecasters at the National Hurricane Center (NHC). For hurricane hunters, there are two main types of missions: permanent and investment.
Fixed mission
The stationary mission is designed to expose the system to tropical cyclone characteristics such as tropical depressions, tropical storms, and hurricanes. The primary goal is to map the center of circulation, monitor winds and pressure changes, and many other factors that cannot be measured in full detail by satellites in space. For stationary missions, Alpha is the most common flight type used to collect data during tropical cyclones.
“The Alpha pattern is our standard pattern for fixed missions, so that’s what people are most familiar with,” said Maj. Jeremy DeHart, a meteorologist and airborne reconnaissance weather officer with the 54th Weather Reconnaissance Squadron. The pattern consists of two diagonal flights. When completed, the flight path forms the Greek symbol for Alpha when the intersection is included.
The geographic directions are the standard points on a compass, which are east, west, south, and north. Diagonal directions indicate northeast, southeast, northwest, and southwest. The more powerful the storm, the easier it is to fly into. “From my perspective as a meteorologist on the plane, the Alpha pattern is the easiest to fly. Since we fly this pattern in strong storms, there’s not much question about the eye of the storm,” DeHart said. “Of course it can be a very choppy flight, but at the end of the day we just fly over the eye of the storm to collect data and send it to the NHC.”
Confirmation task
The primary purpose of a confirmation mission is to determine whether a system meets the definition of a tropical cyclone, which is a storm that doesn’t yet have a name or any real tropical structural features. For confirmation missions, the NHC typically sends an estimated coordinate of where the center of the circulation is believed to be. That’s the starting point that missions typically aim for. However, confirmation missions are inherently quite flexible in terms of flight patterns, simply because there are so many uncertainties about these types of storms. “We never know where we’re going, but we always have to think one or two steps ahead,” DeHart says.
X-shaped, Delta-shaped and box-shaped flight patterns. Photo: NOAA
Air Force Hurricane Hunters have a variety of flight patterns to choose from during confirmation missions, including X-formations, Delta-formations, and Box-formations. These missions are ideal for weak, uncertain storms, according to DeHart. While the X-formation may resemble the Alpha-formation, the aircraft fly at a much lower altitude, around 50 to 100 feet. Once the system becomes a tropical storm or hurricane, the Hurricane Hunters begin flying at higher altitudes, ranging from 5,000 to 10,000 feet, depending on the storm’s strength.
Delta and box patterns typically fly at 5,000 feet or lower. "Delta and box patterns are similar in that we will fly around the predicted edge of the storm's center to see if we can see winds in all four corners of the storm, revealing a closed circulation. If we find a closed circulation, we can find the center of the storm.
NOAA focuses on research
NOAA’s Hurricane Hunters also fly on fixed and confirmation missions, but they are generally research-oriented. They fly in a variety of specialized patterns, with a variety of aircraft, depending on the mission assigned. They also fly a third type of mission called synoptic missions. On fixed missions, NOAA typically flies in figure-four, inverted-four, or butterfly formations. According to Jonathan Shannon, public affairs specialist at NOAA’s Central Aircraft Operations Office, the figure-four and butterfly formations are often used to find the center of a hurricane’s circulation.
For confirmation missions, the aircraft fly in a lawnmower pattern or a right spiral if the area they’re examining has tropical features. Paul Flaherty, chief scientist at NOAA’s Aircraft Operations Center, said the lawnmower pattern helps them map a large area. Once the circulation is fully identified, they’ll switch to a figure-four pattern based on the location of the newly discovered center. The right spiral is a survey mission that provides observations of structure and characteristics, including information about the center of a tornado if one exists.
Additionally, a third type of flight model is often used to sample the surrounding atmosphere, helping forecasters determine the path of the storm. Star 1 focuses on scanning the outer edges of the storm system, while Star 2 helps find the perimeter near the center of circulation.
Regardless of which agency the hurricane hunters belong to, their flight missions form the basis of the National Hurricane Center, which is responsible for critical information about hurricanes. The NHC receives the data and uses it to provide guidance and advice to the public about the storm's strength.
An Khang (According to CNN )
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