NOAA satellites proved critical in forecasts of tornado outbreak

Major Tornado Outbreak Impacts Southeast U.S.-NOAA Environmental Visualization Laboratory

Five days before a powerful storm system unleashed a barrage of deadly tornadoes that tore through six states, NOAA's polar-orbiting satellites helped forecasters at the agency's Storm Prediction Center (SPC) know of the impending danger.

According to the latest SPC figures, there were a total of 312 tornado reports during the entire outbreak, from 8 a.m. EDT on April 25 to 8 a.m. on April 28. NOAA's National Weather Service forecast offices had a 27-minute average warning lead time for the tornado touchdowns.

"We would have not been able to alert the public as early as we did about the strong potential for these violent tornadoes, were it not for the data from NOAA satellites," said Greg Carbin, warning coordination meteorologist at NOAA's SPC in Norman, Okla.

NOAA operates five Polar Orbiting Environmental Satellites, or POES, which circle the globe every 102 minutes, flying 517 miles above the Earth's surface, taking images and measurements of the land, seas and air. POES data track the subtle changes in the environment that can trigger potentially deadly weather conditions – from tornadoes to tropical storms.

In addition to monitoring conditions that spawn tornadoes, POES are vital in forecasting drought, tracking wildfires, ash plumes from volcanoes, global sea surface temperatures and in developing advanced forecasts for storm activity in the tropics.

"The instruments onboard POES give us high-resolution imagery, atmospheric soundings and other valuable data that are fed into NOAA's numerical prediction models that can forecast weather as far out as 10 days," said Steve Lord, director of NOAA's Environmental Modeling Center, in Camp Springs, Md.

POES feature a new data collection system that relays a wide range of environmental observations from sensors around the world -- from stream gauge and sea-level readings, to the migration patterns of wildlife tagged with transmitters – that help scientists stay on top of developing trends.

Complementing NOAA POES are the Geostationary Operational Environmental Satellites, or GOES. NOAA has two GOES in operation, hovering in fixed positions 22,300 miles above Earth's equator, constantly taking images and measurements of severe weather in the Western Hemisphere, including hurricanes headed toward the United States.

"We could not provide skillful hurricane forecasts without the crucial imagery and data from NOAA geostationary and polar-orbiting satellites," said Chris Landsea, Ph.D., science operations officer at NOAA's National Hurricane Center in Miami. Beyond weather and climate, POES and GOES have instruments that can pinpoint the location of distress signals from emergency beacons and help first responders rescue people from potentially life-threatening situations. POES provide current coral reef environmental conditions to quickly identify areas at risk for coral bleaching and aid with management and recovery strategies.

The satellites also monitor disturbances and storms that swirl through space between Earth and the Sun. These disturbances – most commonly, solar flares – can disrupt power grids and Global Position Systems, interfere with airline and military communication.

After the dizzying number of tornadoes in April, and the start of the 2011 hurricane season just weeks away, forecasters will continue relying on NOAA satellites.

"The threat of severe weather is always possible, so our satellites must always be ready and able to deliver the data needed for accurate, life-saving forecasts," said Mary Kicza, assistant administrator for NOAA's Satellite and Information Service.