Early Season Hurricane Hunting

Cylindrical objects called dropsondes released from WC-130J Hercules aircraft helped 53rd Weather Reconnaissance Squadron crews gather valuable meteorological information on some of the most intense recent hurricanes. A new system the Hurricane Hunters installed on all 10 WC-130Js in 2008 helped them obtain a more complete picture of the first named storm in the 2010 hurricane season.

Hurricane Alex became the strongest June hurricane since 1966 to make landfall in the United States and the first to hit the Gulf of Mexico in the season's first month since 1995. The stepped-frequency microwave radiometer, along with the dropsondes, enabled the Hurricane Hunters to show the hurricane strengthen in the final hours before landfall.

"We're getting a good picture of the surface winds of the storm," said Maj. Jeff Ragusa, aircraft commander on the Hurricane Alex mission. "That's a capability we didn't have a couple of years ago.

"The airplane is collecting a horizontal picture of the storm," the major said. "Then, we throw the dropsonde into the mix. As it falls to the surface of the water, it gives us a vertical picture of what's going on beneath the airplane. So we get a horizontal look, as well as a vertical look, to give us as much information as we can to send back to the National Hurricane Center. As the dropsonde is falling, it's sending information, two messages every second, back to the airplane."

The dropsonde is a weather instrument package released by a weather reconnaissance loadmaster into the eyewall and center of the hurricane. As a parachute, or drogue, slows the descent to the ocean, the dropsonde sends current pressure, temperature, humidity, wind speed, direction and Global Positioning System information to instruments on the aircraft, said Tech. Sgt. Amy Lee, a weather reconnaissance loadmaster with the 53rd WRS. That information is then sent by satellite to the National Hurricane Center.

The Hurricane Hunter crew entered the eye of Hurricane Alex in the WC-130J at 5,000 feet when the storm was 130 miles off Mexico's coast. Information gathered by the dropsondes and a radiometer called the "smurf" showed wind speeds had increased to 80 mph and maximum winds were 105 mph in the northeast quadrant of the storm. They also detected the hurricane's lowest minimum pressure had dropped to 958 millibars, said Capt. Douglas Gautrau, an aerial reconnaissance weather officer. Later, the pressure dropped even further to 948 as it moved toward land. By comparison, on Aug. 13, 2004, Hurricane Charley had a low minimum pressure of 941 millibars before it slammed into southeastern Florida with 150 mph winds as a Category 4 storm. Fortunately, Hurricane Alex's winds never exceeded Category 2 strength.

The radiometer, which is located within a pod attached to the aircraft's wing, accurately measures wind speeds directly below the aircraft at the ocean's surface. Hurricane Hunter missions already improve hurricane center forecasts by 30 percent. Major Ragusa said the radiometer enhances the data the aircrew provides for hurricane forecasts. Before the radiometer was added in 2008, Hurricane Hunter crewmembers gathered wind speed information from dropsondes and observations through windows of the WC-130J. The radiometer also measures rainfall rates in a storm; flooding in Mexico and south Texas was a major concern with Hurricane Alex.

"Before, we were getting about 10 observations every hour," Captain Gautrau said. "Now, with the smurf, we're getting data every second, with 3,600 surface wind observations every hour."

The crewmembers on these flights are all Reservists with the 53rd WRS, the only military unit worldwide that flies regular hurricane reconnaissance. Sergeant Lee said she feels a sense of duty more than personal pride for the role she plays in the data the Hurricane Hunters provide to forecasters at the National Hurricane Center.

"I personally feel very sad, when a hurricane makes landfall, for the people in the path of the storm and their loss," Sergeant Lee said. "I'm really happy they were able to get out of the way in time. I'm proud just like anybody else is proud who did a job. I did my duty."