Thursday, January 29, 2009

US Air Force Hurricane Hunters Take On Winter Storms

A WC-130J readies for takeoff at Elmendorf Air Force Base, Alaska. Reserve Hurricane Hunters of the 403rd Wing from Keesler AFB, Miss., deployed for a month to collect weather data ahead of pending winter storms. The data they collect increases the accuracy of the National Weather Service forecast by 10 to 20 percent. (U.S. Air Force photo by Tech. Sgt. James B. Pritchett.)

On the Home Front:

KEESLER AIR FORCE BASE, Miss., Jan. 29, 2009 -- Keesler Air Force Base Airmen and two WC-130J Hurricane Hunter aircraft deployed to Anchorage, Alaska, Jan. 17 for a month-long mission in support of the 2009 Winter Storm Reconnaissance Program.

The 403rd Wing team includes Reserve aircrews, operations, maintenance, aerial porters, and others to improve winter storm forecast models.

Operations are directed by the National Centers for Environmental Prediction, a part of the National Oceanographic and Atmospheric Administration. Like their tropical reconnaissance missions, winter storm routes can keep crews in the air more than 12 hours at a time.

When a tasking for a flight comes in to the 53rd Weather Reconnaissance Squadron's deployed operations center at Elmendorf AFB, Alaska, a WC-130J crew is alerted and maintenance Airmen ensure there is an aircraft ready to fly.

Showtime and pre-flight are similar to the Hurricane Hunters' normal missions except, depending on weather, maintenance teams de-ice the aircraft. Winter missions require crews to fly at altitudes above 30,000 feet, which is higher than they normally fly in tropical weather systems.

"On average, the data we provide along with the (National Oceanic Atmospheric Administration) aircraft lead to a 10 to 20 percent reduction in error in the targeted forecasts," said Lt. Col. Roy Deatherage, the mission commander for the 53rd WRS and an aerial reconnaissance weather officer since 1988. "As a result, numerical forecast guidance issued 48 hours prior to the events become as accurate as 36-hour lead time forecasts."

Use of weather reconnaissance aircraft have improved the forecast models more since 1999 than the previous 25 years of satellite data, according to the NCEP.

Unlike in tropical storms, on a winter mission the crew is not trying to pinpoint the center of the storm, in fact, there may not even be a "storm."

"Often, the crews are flying from one to four days in advance of a potential storm system in the Pacific that appears headed for either Alaska or the continental U.S.," Colonel Deatherage said.

On board the aircraft, the aerial reconnaissance weather officer and weather reconnaissance loadmaster take atmospheric observations at predetermined points along a flight track where the measurements are expected to have the greatest chance of improving the forecasts.

The weather reconnaissance loadmaster drops highly sensitive devices, called dropsondes, which fall at about 2,500 feet per second, in areas of the atmosphere as requested by NCEP officials. As they fall toward the ocean, the dropsondes measure temperature, wind speed, humidity and pressure. Aircraft follow what are called synoptic patterns, which are huge ovals sometimes more than 3,000 miles round-trip.

Colonel Deatherage said that during a typical tropical mission, dropsondes are released at certain points defined by the National Hurricane Center. This is usually four drops every time the aircraft passes through the eye with an additional four to eight per mission in the most significant wind bands. In contrast, Pacific winter missions average 16 to 22 sondes dropped. For impending Atlantic winter missions the average is lower, closer to five.

The information collected is checked onboard and then relayed by satellite to the NOAA Weather Service supercomputer that incorporates it into the agency's numerical prediction models. This information helps "fill-in-the-blanks" or bolster the data in computer climate models that forecast storms and precipitation for the entire U.S.

"The goal is to make a good forecast so cities can be prepared with snow plows, and other snow removal and mitigation equipment to diminish the impact of a winter storm on a city," Colonel Deatherage said. "If they are better prepared, they can recover more quickly. That can be crucial for residents living in harm's way. These forecasts provide people in the path of the storms with warnings that can save lives."

While the Hurricane Hunters are patrolling the north Pacific, NOAA officials are using its Gulfstream G-IV aircraft to fly missions from Honolulu. Between the two units, they are able to cover the parts of the Pacific that directly affect the U.S.

Each year, the 53rd WRS and NOAA rotate deployed locations to better improve the forecasting models. The G-IV flies higher and collects a slightly different data set than that of the WC-130J.

Since 1996, the two organizations have been flying these missions in support of the NCEP.

This project does not encompass the entirety of the 53rd WRS staff's winter taskings. The unit also receives taskings for the East Coast of the U.S. to assist forecasters with pending Nor'easter storms.

The Hurricane Hunters normally fly several of these missions in support of the National Weather Service each season beginning Dec. 1 and ending April 30.

In seasons past, the tropical storm season, beginning June 1 and officially ending Nov. 30, has crossed over into the winter storm season. In 2005, the Hurricane Hunters flew winter storm missions and tropical missions at the same time. That year, the final storm of the hurricane season was recorded in early January.

(Report from a U.S. Air Force news release.)

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