Air Force Hurricane Hunters

Read...

While we're about to focus on the activities of special "Hurricane Hunters" programs that fly into tropical cyclones to collect data, did you know that "Hurricane Hunters" are not the only aviators that contribute to weather analysis and forecasting? As you've learned, the data collected by radiosondes aboard weather balloons contribute to the constant pressure analyses that you're accustomed to (at 500 mb or 300 mb, for example). But, the data captured by instruments on weather balloons is also supplemented by in-situ observations taken by commercial jets. Recall that the standard height of the 300-mb surface is 9,000 meters -- roughly 30,000 feet, which is a representative altitude where commercial aircraft often cruise, for example.

Indeed, the Aircraft Meteorological Data Relay (opens in a new window) (AMDAR), and the Aircraft Communication Addressing and Reporting System (opens in a new window) (ACARS) in the U.S. continuously collect digital communications from commercial aircraft, including weather observations. While these observations aren't freely available to the public in real time, they are incorporated into the initialization of some numerical weather prediction models. But, observations from commercial aircraft are not enough to fully cover the tropics, obviously. To compensate, meteorologists incorporate satellite-derived winds (wind speeds and directions estimated by satellite at specified altitudes), which we'll cover later in this lesson.

To get back to the topic at hand (aircraft observations over the tropics), I point out that commercial and private aircraft prudently fly around big storms. However, groups of intrepid aviators in the U.S. Air Force Reserve and NOAA, popularly known as "Hurricane Hunters," are available to fly reconnaissance missions into tropical cyclones whenever they develop. During the off-season, they also fly into fierce winter storms that rage along the Atlantic and Pacific Coasts. 

U.S. Air Force Hurricane Hunters

Stationed at Keesler Air Force Base in Biloxi, Mississippi, the U.S. Air Force Hurricane Hunters formally belong to the 53rd Weather Reconnaissance Squadron. During hurricane season, the squadron is ready to spring into action at any sign of a tropical cyclone developing in the region spanning approximately from the mid-Atlantic Ocean (longitude 55 degrees West) to the Caribbean Sea and the Gulf of Mexico. Hurricane Hunters also fly reconnaissance into tropical cyclones over the central and eastern Pacific Ocean, particularly those that might pose a threat to Hawaii or mainland North America. U.S. Air Force Hurricane Hunters rely on the durable WC-130-J aircraft (see below) equipped with an arsenal of weather instruments to monitor tropical cyclones. 

NOAA Hurricane Hunters

The Air Force Hurricane Hunters don't have the "market cornered" on hurricane hunting. Indeed, NOAA also flies specially equipped aircraft into hurricanes to collect observations. But, the mission of the NOAA Hurricane Hunters goes beyond just routine reconnaissance. The Hurricane Research Division (opens in a new window) (HRD), under the auspice of the Atlantic Oceanographic and Meteorological Laboratory (AOML) within NOAA, flies specially equipped aircraft into hurricanes and other tropical weather systems to conduct research to advance the scientific understanding of the tropics and, in the process, improve weather forecasts. For this reason, NOAA Hurricane-Hunter flights often serve as testing grounds for new and experimental instruments and strategies for making various atmospheric measurements (which may or may not eventually become operational on all Hurricane Hunter flights and in other contexts). HRD has a long and storied history in the pursuit of excellence in hurricane research, which you can read about (opens in a new window), if you're interested. The NOAA Hurricane-Hunter research fleet (see below), which consists of two WP-3D turboprops (sometimes referred to as "NOAA P-3s") and a Gulfstream jet, operate from NOAA's Aircraft Operations Center (opens in a new window) in Lakeland, Florida.

Flying into the storm

For most of the missions flown into hurricanes, the standard flight level is 700 mb (recall that the standard 700-mb height is 3,000 meters, or around 10,000 feet). When forecasters at the National Hurricane Center spot a suspicious cluster of tropical showers and thunderstorms on satellite imagery, Hurricane Hunters may fly a Low-level Investigative Mission at 500 or 1500 feet above the sea surface. At such altitudes, wind data can reveal a closed, low-level circulation that allows forecasters to upgrade the system to a tropical depression. As the depression develops into a tropical storm, Hurricane Hunters typically increase the flight level to 850 mb (recall that the standard 850-mb height is 1,500 meters, or about 5,000 feet). As the tropical cyclone further intensifies, Hurricane Hunters increase their flight level to 10,000 feet (the conventional maximum flight level inside hurricanes), unless they need to deviate due to special circumstances (such as multiple planes flying the storm at once: They must stay at least 2,000 feet in altitude apart). I should note here that Hurricane Hunters fly at higher altitudes on other missions (such as reconnaissance in winter storms). 

When Hurricane Hunters enter a tropical cyclone, they often fly an alpha pattern (the animation below will give you a general idea of what one looks like), or a series of alpha patterns. After flying the first diagonal across the storm (usually at least 105 nautical miles (120 statute miles) on either side of the center), executing a successful alpha pattern amounts to simply making a series of left-hand turns. In this way, the plane never flies directly into the teeth of the wind (remember that northern hemispheric low-pressure systems have a counterclockwise circulation). Avoiding the strong direct headwinds allows the aircraft to save fuel and fly longer missions. Moreover, the aircraft collects data in all four quadrants of the storm after making only two passes through the center. The aircraft passes through the center about every two hours and continues the pattern until the next plane is ready to take its place if NHC wants fixes on the storm every six hours and "round-the-clock" surveillance. If NHC wants fixes on the storm less frequently (every 12 or 24 hours, for example), then there's no immediate replacement aircraft when the mission is complete (each mission lasts roughly eight hours, on average).

Alpha Pattern (0:09)

Hurricane Hunters may execute other flight patterns or fly at other altitudes, depending on the goals of the mission. NOAA's Gulfstream jet, for example, often flies missions to collect observations in the environment around and ahead of hurricanes. Often flying at altitudes as high as 45,000 feet, the Gulfstream jet can assess the winds that steer these storms. For instance, as Hurricane Dorian moved perilously close to the Southeast coast on September 4, 2019, the Gulfstream jet flew around the periphery of the storm and emphasized sampling the environment to its east an northeast (to ensure the best understanding of the environment the storm was going to move into), so its flight-track map (opens in a new window) bears no resemblance to an alpha pattern.

I should note here that the range of reconnaissance aircraft varies from 2,200 to 3,600 miles (the range depends, in part, on flight altitude). Thus, newly forming tropical cyclones over the eastern and central Atlantic Ocean are, for all practical purposes, out of range for reconnaissance aircraft. In its place, tropical forecasters rely on remote sensing from satellites to assess the intensity and structure of storms (more to come later in this lesson). 

To see what the Hurricane Hunters are up to on any given day, check out the Tropical Cyclone Plan of the Day (opens in a new window). If you're interested in learning more about the operations of the Hurricane Hunters, you may enjoy the resources in the Explore Further section below. Otherwise, up next, we'll turn our attention to the instruments and sensors that Hurricane Hunters have in their arsenal to collect crucial data.