UNIVERSITY PARK, Penn. -- Most people remember the Blizzard of 1996, but when Jon D. Radakovich recalls the blizzard, he can explain why it occurred. Working with Dr. Hampton N. Shirer, associate professor of meteorology, Radakovich, who was then a Penn State meteorology undergraduate, learned how to model the evolution of the blizzard using equations that capture the dynamics of storm development.
Using these equations -- which depend on air pressure, temperature, wind direction and wind speed at various levels in the atmosphere -- Radakovich identified the key atmospheric conditions that produced the blizzard. One of his most significant findings was that the surface low modeled by the equations coincided with the actual position of the surface low when the storm was at its most intense stage.
The blizzard caused the East Coast to report record snowfalls in numerous cities. During cleanup efforts, a warm rainstorm followed the blizzard's path. The melting snow and additional heavy rainfall caused people to abandon their shovels in search of higher ground, as flooding was reported throughout much of the eastern United States.
"Approximately $3 billion in damage and 187 deaths were caused by the Blizzard of 1996 and the flooding that followed," says Radakovich, currently a graduate student in Penn State's meteorology department. "Virginia, Maryland, West Virginia and Pennsylvania were buried under more than 30 inches of snow in some areas."
In order to diagnose the atmospheric conditions that resulted in this damage, Radakovich used two equations -- the Sutcliffe development equation and the quasi-geostrophic geopotential tendency equation.
For widespread heavy snowfall to occur, air must be rising rapidly in the atmosphere for long periods of time and over large areas. The Sutcliffe development equation models mechanisms in the lower levels of the atmosphere (from 5,000 to 10,000 feet) that cause the air to rise, while the quasi-geostrophic geopotential tendency equation models mechanisms in the middle levels of the atmosphere (from 15,000 to 20,000 feet) that result in rising air. The second method is the newer of the two and a primary one used by modern forecasters.
Radakovich compared the computed results from both equations with those for the actual storm. He found that the older Sutcliffe development equation proved to be the more accurate model. Thus, mechanisms in the lower levels of the atmosphere dominated the development of the Blizzard of 1996. The lack of success using the quasi-geostrophic geopotential tendency equation suggests that old methods such as the Sutcliffe scheme are still very useful and, in some cases, provide a better tool, as for the Blizzard of 1996.
"Because of our success using the Sutcliffe development equation," says Radakovich, "Dr. Shirer and I recommend that the model be placed on the Department of Meteorology computer system. Students will then have the opportunity to witness firsthand these applications of dynamics. From our results, we believe that the Sutcliffe development equation may be valuable as a forecasting tool."
Radakovich provides a more detailed account of his research procedures and results in his honors thesis, "A Case Study of the Evolution of the Blizzard of 1996 Through the Application of Quasi-Geostrophic Theory."