The four-dimensional (4-D) MclDAS system is applied to a numerical simulation of the rapid development phase of the Presidents' Day cyclone. Selected frames from a videotape of the model simulation are presented to illustrate the evolution of the upper- and lower-tropospheric potential vorticity maxima prior to and during rapid cyclogenesis. The 4-D structure of various airstreams converging toward the cyclone center are also displayed. Our experience with 4-D displays of model output indicates that these systems offer a tremendous opportunity to manage and dissect the information content inherent in numerical simulations. The production of the visualizations of the Presidents' Day cyclone also confirmed a need for an interactive system capable of producing various perspectives in real time, a requirement being addressed with the development of a new workstation at the University of Wisconsin Space Science and Engineering Center.
* Space Science and Engineering Center, University of Wisconsin—Madison, Madison, Wl 53706
** Meteorological Operations Divisions, National Meteorological Center, Camp Springs, MD 20746
+ General Sciences Corporation, Code 612, NASA/GSFC, Greenbelt, MD 20771