Background and format information on the 4-panel simulation figures:

The four-panel maps of the simulation results are organized as in early publications of COMPASS-type investigations. Each page contains four images, all featuring the same values for the "e," "c," "k," "f," "p," and "h" parameters, but with the 2x2 matrix of combinations of the two values of each of the "m" and "n" parameters. The two left-hand images are both for small values of "m", while the two right-hand images are both for large values of "m." The two lower images are for small values of "n," while the upper images are for large values of "n." As "m" increases, the low-level lapse rates (above the LFC) increase, and the altitude of maximum parcel buoyancy decreases. As "n" increases, the low-level vertical shear of the environmental wind increases, and the altitude of the maximum v-wind in our semicircular hodographs decreases.

The fields depicted in each image are designed to give a basic understanding of storm structure and intensity. The color shades represent low-level rainwater content, and describe the size, shape and intensity of the storm's precipitation shield. The line contours show the location and strength of the storm's updraft, using a contour interval of 3 m/s. The updraft contours are shown at an altitude roughly 2 km above cloud base; this tends to give a representative view of the storm's midlevel updraft, but is not necessarily the level where the updraft is strongest. Note that these simulations are for storms that exist in sheared environments, so that the locations of the peak updrafts and precipitation cores are not generally exactly coincident. The displacement of the precipitation core from the main updraft is an important feature of many convective storms. The vectors depict the near-surface ground-relative winds, with undisturbed warm air having wide arrowheads, and the storm's rain-cooled outflow having narrow arrowheads. Note that some storms ingest a high proportion of undisturbed warm air (many of the vectors beneath the midlevel updraft have wide arrowheads), while others are undercut completely by rain-cooled air (most or all of the vectors beneath the midlevel updraft have narrow arrowheads). These kinds of morphological differences can have a profound impact on storm intensity and longevity.

The simulations are designed to depict the evolution of the first two hours of a storm's life, but not all the storms survive the full two hours. In particular, some of the small "m" and small "n" storms, especially in cases of small "e", dissipate quickly during the second hour. For each of the panels shown in the map figures, the mature phase of the most significant right-moving storm is displayed, and the time of the simulated model storm's evolution is printed next to each panel for reference. For storms that remain healthy during the second hour, this time will always lie somewhere between 60 and 120 minutes. For the storms that quickly dissipate, we have elected to show storm structure at some point during the first hour. Thus, storms that do not survive for two hours are always identified by having a time stamp less than or equal to 60 minutes in the figures.


All Images © Copyright Eugene W. McCaul, Jr.