Fact Sheet United States Air Force Reserve

Weather Reconnaissance

Weather data are needed from areas where it is impractical or impossible to operate ground observation stations, or where weather satellites cannot provide complete information. To fill this need, Air Force aerial weather reconnaissance aircraft fly long routes over the ocean to collect and transmit weather observations and atmospheric soundings.

Today, a typical hurricane warning costs an estimated $192 million due to preparation, evacuation, and lost commerce. Narrowing the warning area could save $640,000 per mile or more, and also lend greater credibility to forecasts and foster more controlled and limited coastal evacuations. Furthermore, as coastal populations continue to grow, evacuation decisions need to be made earlier; a few areas already require over 48 hours to clear in advance of a major hurricane.

Studies have shown the high accuracy data from our Air Force Reserve and NOAA aircraft have improved the forecast accuracy by about 25%. Aircrews in these storms also have detected sudden, dangerous changes in hurricane intensity and movement, which are currently very difficult to detect by satellite alone. The Hurricane Hunters are proud to serve as a vital link in the hurricane surveillance and warning network, alerting vulnerable populations.

Currently, Air Force Reserve personnel at Keesler AFB, Miss., have the sole responsibility in the Department of Defense for aerial weather reconnaissance, including hurricane reconnaissance. These men and women are assigned to the 53rd Weather Reconnaissance Squadron, the “Hurricane Hunters.”

The Air Force uses ten WC-130 aircraft to accomplish these weather missions. Six people comprise the crew: aircraft commander, co-pilot, flight engineer, navigator, weather officer, and a dropsonde system operator. The weather officer collects flight-level data at 30-second intervals, including position, temperature, dewpoint, and pressure. The weather officer also takes RECCO observations enroute, and VORTEX messages in the eye of the storm, which include elements visually observed.

The dropsonde system operator makes periodic dropsonde releases. A dropsonde is a parachute-born weather sensing canister which, as it falls to the surface of the ocean, radios back to the weather aircraft the temperature, humidity, pressure and winds inside the storm. Of particular importance is the data from the eye of the storm, which affords the National Hurricane Center the most accurate measurement of the tropical cyclone’s location and intensity.

All weather information is processed and encoded aboard the aircraft, then transmitted by satellite communication directly to the National Hurricane Center for input into the national weather data networks. These data are provided freely to all member nations of the World Meteorological Organization.

Tropical Cyclone Missions

When conditions favorable for hurricane development are observed, either by surface observation or by weather satellite, the National Hurricane Center in Miami, Fla., alerts the flying weather crews. Their job: to determine the precise location, motion, strength, and size of the storm, and transmit the information by satellite to the National Hurricane Center.

The first missions are often flown at low-level, between 500 and 1500 feet. These low-level investigative missions are flown to determine if the winds near the ocean surface are blowing in a complete, counter- clockwise circle, then to find the center of this closed circulation. This is the first stage of a developing tropical cyclone.

As the storm builds in strength, the WC-130s enter a storm at low-level, 5000, or 10,000 feet of altitude, choosing higher altitudes as the storm becomes more severe. The tops of the storm clouds may reach up to 40,000 or 50,000 feet, so the aircraft do not fly over the storm, but go right through the thick of the weather to collect the most valuable information. The Alpha Pattern flown through the storm looks like an "X". The crews fly at least 105 miles in each corner of the storm to map the extent of the damaging winds, and pass through the eye every two hours, continuing the pattern until the next aircraft is ready to take its place in the around-the-clock surveillance of the storm.

Hurricanes are made up of dense thunderstorms, which often contain severe turbulence and heavy rain. The eye is usually surrounded by a solid ring of thunderstorms called the eyewall, and is where the strongest winds are usually found. Sometimes the clouds and rain are so thick, the aircraft’s wing tips are barely visible. The storm’s eye, by contrast, is virtually cloud free and is comparatively calm.

Winter Storm Missions

From November 1st to April 15th, the National Center for Environmental Prediction (NCEP) may call upon the 53rd to fly missions into winter storms off the coasts of the United States. The crews collect data ahead of weather systems before they move off the eastern seaboard, to help determine if the conditions are right for the storms to intensify and create the Nor'easter blizzards. In the past two winters, the Hurricane Hunters also flew winter storms in the Gulf of Alaska before they struck the Pacific northwest. Research showed improvement in the forecast accuracy with these flights.

The aircraft are flown at 30,000 feet, and an array of dropwindsondes are released along the route. The predetermined tracks take six to eleven hours to complete. Typically, one to three missions are flown per major winter storm event.

Research

Occasionally, the 53rd may fly participate in weather research projects in the national interest. The aircraft are capable of collecting research-quality data, every 10 seconds, and even down to 1-second intervals. In January and February of 1997, the 53rd joined scientists from several countries in the Fronts and Atlantic Storm Tracks Experiment (FASTEX) to study the intensification of winter storms as they cross the ocean.

The squadron also has the unique charter to release large drifting data buoys in the path of hurricanes. In 1996, the 53rd released a series of four buoys in Hurricane Fran. The buoys drifted for days, and gathered very valuable data in the storm environment, and even scored a direct hit when the eye of Fran overtook the buoy.

In some of the projects, the 53rd may join meteorological aircraft from the National Center for Atmospheric Research (NCAR) or The Department of Commerce's National Oceanic and Atmospheric Administration (NOAA). NOAA operates two WP-3 Orion turboprops (similar to the WC-130) primarily for hurricane research, and fly about 2% of the routine hurricane surveillance missions, in areas where the Air Force does not have permission to fly. NOAA recently acquired a Gulfstream G-IV jet to collect high-altitude information around the periphery of the hurricanes.

For more information, visit the Hurricane Hunter website at www.hurricanehunters.com.

(CURRENT AS OF OCTOBER 1999)