From December 12, 1997 through December 14, 1997, the eastern third of the United States experienced a severe turbulence outbreak in the mid and upper levels of the troposphere rarely seen by the aviation community. During the three days, the Aviation Weather Center (AWC) of the National Weather Service had almost continuous Significant Meteorological (SIGMET) advisory issuances for severe turbulence conditions covering large areas of the Ohio and Tennessee River Valleys, and the Middle Atlantic Coast States. Over 200 pilot reports (PIREPS) of severe turbulence were recorded during the event, including three reports of extreme turbulence. The synoptic atmospheric features that triggered the outbreak are shown, as is the performance of the AWC's meteorologists in forecasting timely SIGMET advisories for the event. In addition, computer-generated numerical guidance forecast aids routinely used by AWC forecasters in turbulence prediction are examined. Both the large areal extent and duration of the outbreak in one location makes this case a unique aviation weather event; a superoutbreak of potentially hazardous turbulence conditions that affected the commercial and general aviation flights through the region, and the flying public on those airplanes.
The 8th Conference on Aviation, Range, and Aerospace Meteorology