Because weather patterns and storm systems that impact the United States, such as the recent New Year's storm, often develop over the Pacific Ocean, the National Oceanic and Atmospheric Administration will send highly-sophisticated reconnaissance aircraft to drop instruments over portions of the ocean to improve forecasts of weather systems and provide insight into turbulence, an extreme hazard to aircraft.

"Observing and understanding atmospheric conditions in the Pacific Ocean is important to improving U.S. weather forecasts," said Louis Uccellini, director of the National Weather Services' Office of Meteorology. "This can be a challenge because we don't have many of the traditional observing systems out there. The missions will help the National Weather Service and research community understand where extra data are needed."

The two missions are called the Winter Storm Reconnaissance program and SCATCAT (Severe Clear Air Turbulence Collides with Air Traffic). The Winter Storm Reconnaissance program is sponsored by the National Oceanic and Atmospheric Administration's National Weather Service in cooperation with NOAA's Aircraft Operations Center and the U.S. Air Force Reserves. SCATCAT is a collaborative effort between NOAA, the Federal Aviation Administration, the National Center for Atmospheric Research in Boulder, Colo., and the Naval Research Laboratory in Monterey, Calif.

The Winter Storm Reconnaissance program is an outgrowth of two successful field experiments that took place last winter in which NOAA's Gulfstream IV (G-IV) hurricane reconnaissance and P-3 hurricane research aircraft and the U.S. Air Force Reserve C- 130 planes helped collect valuable data that improved short-range weather forecasts for many of the devastating storms that occurred during the 1997/98 El Niño.

During the 1999 missions, the G-IV will fly nine missions out of Honolulu, Hawaii, and the U.S. Air Force Reserve will fly 10 missions with the C-130 planes out of Anchorage, Alaska, to collect critical atmospheric data.

Throughout these flights, scientists will release weather instruments known as dropwindsondes into the weather systems that are likely to develop into strong storm systems over the United States. The most critical areas for data collection will be identified on a case-by-case basis by the National Weather Service in collaboration with scientists from Pennsylvania State University and the Massachusetts Institute of Technology.

The dropwindsondes collect temperature, wind, moisture and pressure data from the flight level (30,000 to 45,000 feet) until they reach the ocean. The soundings provide scientists with a complete picture of the atmosphere at a given point in time. These data are relayed in real-time to the scientists aboard the aircraft and to operational numerical computer models that generate weather and climate forecasts.

"Although this technique of gathering data in areas where they can be most beneficial in improving our weather forecasts is relatively new, it is already being transferred into operational use," said Stephen Lord, deputy director of the NWS's Environmental Modeling Center. "The observations will be used in real-time to start the numerical models to generate better forecasts for critical weather events in the one- to four-day timeframe."

In addition to the Winter Storm Reconnaissance flights, researchers are conducting an experiment called SCATCAT. This collaborative effort will attempt to take observations within turbulence at altitudes of trans-Pacific commercial airline flights. Clear air turbulence is extremely dangerous for aircraft passengers and crew, as the aircraft can either lose gravity or be thrown upward with tremendous force. Researchers will fly three dedicated SCATCAT missions with the NOAA G-IV aircraft from Honolulu between Jan. 16 and Feb. 15. The scientists will also use data collected during the Winter Storm Reconnaissance flights to supplement SCATCAT.

As with the Winter Storm Reconnaissance program, SCATCAT scientists will deploy dropwindsondes into turbulent areas of the jet stream to look at the structure or internal waves of the jet stream between 45,000 and 27,000 feet, the flight altitude of major airlines. The data will be used to verify experimental turbulence prediction models at NOAA's Forecast Systems Lab, the National Center for Atmospheric Research and the Naval Research Laboratory to learn how operational National Weather Service forecast models might be improved to give pilots more accurate warnings of turbulence. In addition, the SCATCAT pilots will steer the G-IV aircraft directly into turbulent areas of the jet stream to gather even more data on a horizontal scale.

"This is the first time we're going to document the structure of the atmosphere responsible for causing turbulence," said Mel Shapiro, NOAA/Environmental Technology Laboratory SCATCAT project director. "We hope this experiment will increase our understanding of why some jet streams have severe turbulence and others don't."

"Aviation safety is a high priority for NOAA as we provide the numerical models and forecasts for commercial, military and civilian planes to plan flight routes," said Cecilia Girz, head of the NOAA/Forecast Systems Lab's turbulence program.

The C-130 flights out of Anchorage are scheduled to begin Jan. 12 and the G-IV flights out of Hawaii are scheduled for Jan. 16. The aircraft will fly a range of 2,800 to 3,200 nautical miles in approximately eight to 11 hours. The plan is for the aircraft to return to their base after each mission; however, if the weather situation demands, the aircraft may land at an alternate site.

A near real-time evaluation of the forecast impact of the Winter Storm Reconnaissance data and other related information will be available on the Internet at
http://sgi62.wwb.noaa.gov:8080/ens/target/wsr.html

Further information on SCATCAT and clear air turbulence is available on the
Internet at http://www-frd.fsl.noaa.gov/mab/scatcat/

Editor's Note: The NOAA G-IV will be available for media tours at the American Meteorological Society's 79th Annual Conference in Dallas, Texas, on Thursday, Jan. 14, 1999, from 9:00-10:30 a.m. at the Love Field airport. The Dallas/Fort Worth Office NWS Forecast Office and the AMS are arranging and coordinating this media event. If you are interested in attending and for directions, please contact Curtis Carey via pager at (888) 448-9118.

Media are invited to participate in Winter Storm Reconnaissance and SCATCAT missions. For details on getting on the flights, flight dates and times from Honolulu, contact: Delores Clark, NOAA Public Affairs, Honolulu at (808) 532-6411.

For details on getting on the U.S. Air Force Reserve C-130 flights, flight dates and times from Anchorage, contact: Michele Rivera at Keelser Air Force Base at (228) 377-2056, or e-mail at Michele.Rivera@bix.afrc.af.mil.; or Lt. Col. Denny Price in Anchorage at (907) 552-0448.

For information about NOAA's Aircraft Operations Center and Office of NOAA Corps Operations, see: http://www.nc.noaa.gov